电气供配电系统大学毕业论文英文文献翻译及原文
毕业设计外文原文+翻译(电力系统)
对称相电压
在图 2-10 中,三相电源的终端呗标记为 a、b、c，电源相电压标记为Ean ， Ebn ，Ecn ，当电源的三相电压有相同的幅度，任意两相之间互差 120 度角时，电 源是对称的。当以Ean 作为参考相量时，相电压的幅值是 10v，对称三相相电压 如下所示：
Ean =100 Ebn 10 120 10 240 （2.5.1） Ecn 10 120 10 240
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河南理工大学 HENAN POLYTECHNIC UNIVERSITY
480 30 Ean 3 IA= Z L ZY 180 30 40 3 277.1-30 （0.0872+j0.9962）（ + 7.660+j6.428） 277.1-30 277.1-30 = = =25.83-73.78 A （2.5.18） （7.748+j7.424） 10.7343.78 I B 25.83166.22 A I C 25.8346.22 A
Ebn Eab
Ebc
30
Ean
Ecn
Eca
（a）向量图
b
Eab Ebn
a
Ebc Ean Eca
c
Ecn
（b）电压三角形
图 2.12 正序三相 Y 形连接系统相电压和相线电压
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河南理工大学 HENAN POLYTECHNIC UNIVERSITY
对称线电流
在图 2-10 中，因为从电源到负载的中性线的阻抗忽略不计，所以 n 与 N 之间是 同电位的，即EnN =0。因此每一相都可以列一个单独的 KVL 方程，经观察，线电 流为：
I a Ean ZY I b Ebn ZY （2.5.7） I c Ecn ZY
电气专业毕业设计英文文献
电气专业毕业设计英文文献电气专业毕业设计英文文献外文资料与中文翻译外文资料:Relay protection present situation anddevelopment一、Relay protection development present situationElectrical power system's swift development to the relay protection proposed unceasingly the new request, the electronic technology, the computer technology and communication's swift development unceasingly has infused the new vigor for the relay protection technology's development, therefore, the relay protection technology is advantageous, has completed the development 4 historical stage in 40 remaining years of time.After the founding of the nation, our country relay protection discipline, the relay protection design, the relay factory industry and the relay protection technical team grows out of nothing, has passed through the path which in about 10 year the advanced countries half century pass through. In the 50s, our country engineers and technicians creatively absorption, the digestion, have grasped the overseas advanced relay protection equipment performance and the movement technology [1], completed one to have the deep relay protection theory attainments and the rich service experience's relay protection technical team, and grew the instruction function to the national relay protection technical team's establishment. The Achengrelay factory introduction has digested at that time the overseas advanced relay technique of manufacture, has established our country own relay manufacturing industry.Therefore our country has completed the relay protection research, the design, the manufacture, the movement and the teaching complete system in the 60s. This is the mechanical and electrical -like relay protection prosperous time, was our country relay protection technology development has laid the solid foundation.From the late 50s, the transistor relay protection was starting to study. In the 60s to the 80s in is the time which the transistor relay protection vigorous development and widely uses. And the Tianjin University and the Nanjing Electric power Automation Plant cooperation research's 500kv transistor direction high frequency protection develops with the Nanjing Electric power Automation Research institute the transistor high frequency block system is away from the protection, moves on the Gezhou Dam 500 kv lines [2], finished the 500kv line protection to depend upon completely from the overseas import time.From the 70s, started based on the integration operational amplifier's integrated circuit protection to study. Has formed the complete series to the late 80s integrated circuit protection, substitutes for the transistor protection gradually. The development which, the production, the application protected to the early 90s integrated circuit were still in the dominant position, this was theintegrated circuit protection time. The integrated circuit power frequency change quantity direction which develops in this aspect Nanjing Electric power Automation Research institute high frequency protected the influential role [3], the Tianjin University and the Nanjing Electric power Automation Plant cooperation development's integrated circuit phase voltage compensation type direction high frequency protection alsomoved in many 220kv and on the 500kv line.Our country namely started the computer relay protection research from the late 70s [4], the institutions of higher learning and the scientific research courtyard institute forerunner's function. Huazhong University of Science and Technology, the Southeast University, the North China electric power institute, Xi'an Jiaotong University, the Tianjin University, Shanghai Jiaotong University, the Chongqing University and the Nanjing Electric power Automation Research institute one after another has developed the different principle, the different pattern microcomputer protective device. in 1984 the original North China electric power institute developed the transmission line microcomputer protective device first through the appraisal, and obtained the application in the system [5], has opened in our country relay protection history the new page, protected the promotion for the microcomputer to pave the way. In the main equipment protection aspect, the generator which the Southeast University and Huazhong University of Science and Technology develops loses magnetism protection, the generator protection and the generator? Bank of transformers protectionalso one after another in 1989, in 1994 through appraisal, investment movement. The Nanjing Electric power Automation Research institute develops microcomputer line protective device alsoin 1991 through appraisal. Tianjin University and Nanjing Electric power Automation Plant cooperation development microcomputer phase voltage compensation type direction high frequency protection, Xi'an Jiaotong University and Xuchang relay factory cooperation development positive sequence breakdown component direction high frequencyprotection also one after another in 1993, in 1996 through appraisal. Hence, the different principle, the different type's microcomputer line and the main equipment protect unique, provided one group of new generation performance for the electrical power system to be fine, the function was complete, operation reliable relay protection installment. Along with the microcomputer protective device's research, in microcomputer aspects and so on protection software, algorithm has also made many theory progresses. May say that started our country relay protection technology from the 90s to enter the time which the microcomputer protected.二、future development of Relay protectionThe future trend of relay protection technology is to computerization, networking is intelligent, protect, control, measure and data communication developing by integration. The principles of protection of electric power circuits are quite independent of the relay designs which may be applied. For example, if the current to an electriccircuit or a machine is greater than that which can be tolerated, it is necessary to take remedial action. The device for recognizing the condition and initiating corrective measures would be termed as an over-current relay regardless of the mechanists by whichthe function would be accomplished. Because the functions of electromechanical devices are easily described, their performance wills ever as a basis for presenting a description of relays and relay systemsin general.Relays must have the following characteristics: Reliability---The nature of the problem is that the relay may be idle for periods extending into years and then be required tooperatewith fast responds, as intended, the first time. The penalty for failure to operate properly may run into millions of dollars.Selectivity---The relay must not respond to abnormal, but harmless, system conditions such as switching transients or sudden changes in load.Sensitivity---The relay must not fail to operate, even in borderline situations, when operation was planned.Speed---The relay should make the decision to act as close to instantaneously as possible. If intentional time delay is available, it should be predictable and precisely adjustable.Instantaneous---The term means no intentional time delay.There are several possible ways to classify relays: by function, by construction, by application. Relays are one of two basic types of construction: electromagnetic or solid-state. The electromagnetic type relies on the development of electromagnetic forces on movable members,which provide switching action by physically opening or closing sets of contacts. The solid state variety provides switching action with no physical motion by changing the state of serially connected solid state component from no conducting to conducting(or vice versa). Electromagnetic relays are older and more widely used; solid state relays are more versatile, potentially more reliable, and fast.1)ComputerizationWith swift and violent development of computer hardware, computer protect hardware develop constantly even. The power system is improving to the demand that the computer protects constantly, besides basic function protected, should with trouble information of the large capacity and data the long-term parkingspace also, fast data processing function, strong communication capacity, network in order to share the whole system data , information , ability , network of resource with other protection , control device , dispatcher, high-level language programming ,etc.. This requires computer protector to have function which is equivalent to a pc machine. In computer is it develop initial stage to protect, is it make with one minicom relay protection install to imagine. Because the small-scale organism was accumulated greatly, with high costs at that time, dependability was bad, this imagined it was unrealistic . Now, exceed the minicomputer of those years greatly with computer protector size similar worker function , speed , memory capacity of accusing of machine, so make with complete sets of worker person who accuse of opportunity of relay protection already ripe, this will be one of the developing direction that a computer is protected . Tianjin university is it spend whom transformation act as continue the electric protector with computer protector structure self-same one worker person whoaccuse of to develop into already. The advantage of this kind of device is as follows, (1)it have functions of 486pc,it can meet to at present and it is various kinds of function demand where computerprotect future. (2)The size and structure are similar to present computer protector , the craft is superior, takes precautions against earthquakes , defends overheatedly and defending the electromagnetic ability of interfering strongly, can operate it in very abominable working environment , the cost is acceptable.(3)Adopting std bus or pc bus, hardware module , can select different module for use to different protection wantonly , it is flexible , easy to expand to dispose.It is an irreversible development trend to continue the computer , computerization of the electric protector. But to how better meet power system demand, how about raise the dependability of relay protection further, how make heavy economic benefits and social benefit, need carry on concrete deep research.2) NetworkedComputer network become the technological pillar of information age as message and data communication tool, made the mankind producing , basic change has taken place in the appearance with social life. It isinfluencing each industrial field deeply, has offered the powerful communication means for each industrial field too. Up till now, except that protect differentially and unite protecting vertically, all continue electric protector can only react that protect the electric quantity of installing office. The function of relay protection is only limited to excising the trouble component too , narrow the accident coverage. This mainly lack the powerful data communication means. Having already put forward the concept protected systematically abroad, this meant the safe automatics mainly at that time. Because the function of relay protection is not only limited to excising the trouble component and restriction accident coverage (this is primary task), the peace and steadiness that will be guaranteed the whole system run . This require each protect unit can share the whole operation and data , trouble of information of system, each protect unit and coincident floodgate device coordination on the basis of analysing the information and data, guarantee systematic peace and steadiness run . Obviously , realize the primary condition that system protect the whole system every protector of capitalequipment link with the computer network, namely the one that realized the computer protector is networked. This is totally possible under present technological condition .To general protecting systematically , realize the computer networking of the protector has a very great advantage too. It continue electric trouble not the less many in information not systematic can receiving protector ,for trouble nature , judgement and the trouble,trouble of position from measuring the less accurate. Protect to self-adaptation research of principle pass long time very already , make certain achievement too, but should really realize protecting the self-adaptation to the operation way of the system and trouble state, must obtain more system operating and trouble information , the computer that only realizes protecting is networked, could accomplish this . As to the thing that some protectors realize computer networking , can improve the dependability protected . Tianjin Sanxia vltrahigh voltage many return circuit bus bar , 500kv of power station , put forward one distributed principle that bus bar protected to future 1993 such as university, succeed in developing this kind of device tentatively. Principle its bus bar is it disperse several (with protect into bus bar back to way the same ) bus bar protect Entrance to protect traditional concentration type, disperse and install it in every return circuit is protected and rejected , each protect the unit to link with the computer network, each one protects the electric current amount that the unit only inputs a return circuit , after changing it into figure amount, convey to the protection units of other return circuits through the computer network, each protect the unit according to the electric current amount of this return circuit and electric current amount of other return circuits gotfrom computer network, carry on bus bar differential calculation that protect, if result of calculation prove bus bar trouble jump format return circuit circuit breaker only, isolate the bus bar of the trouble. At the time of the trouble outside the bus bar district , each protect the unit and calculate for movements of the external trouble. This kind protect principle by distributed bus barthat network realize with computer, bus bar protect principle have higher dependability than traditional concentration type. Because if one protect unit interfere or mistake in computation and when working up by mistake, can only jump format return circuit , can is it make bus bar to be whole of malignant accident that excise to cause wrong, this is very important to systematic pivot with supervoltage bus bar of hydropower station like SanxiaCan know computer protector networked to can raise and protect the performance and dependability greatly while being above-mentioned, this is an inexorable trend that a computer protects development 3) Protect , control , measure , data communication integratesOn terms that realize computerization of relay protection and networked, the protector is a high performance , multi-functional computer in fact, it is a intelligent terminal on the computer network of whole power system. It can obtain any information and data of operating and trouble of the power system from network , can convey network control centre or any terminal function , and can also finish the measurement , control , data communication function in there is no normal running of trouble cases, namely realize protecting ,controlling , measuring , data communication integrates.At present, for measurement, need that protects and controlling, all equipment of the outdoor transformer substation, two voltage, electric current of voltage transformer, circuit,etc. must with control cable guide to the top management room for instance. Lay control cable take a large amount of investment, make the very much complicated returncircuit 2 times in a large amount. But if above-mentioned protection, control, measure, data communication integrated computer device, install in to is it by the equipment , protect into voltage , electric current amount of equipment in device this after changing into the figure amount to protect outdoor transformer substation on the spot, send to the top management room through the computer network, can avoid a large number of controlcables . If use optic fibre as the transmission medium of the network , can avoid and interfere electromagnetically. The photocurrent mutual inductor of now (ota ) and photovoltage mutual inductor (otv ) have been already during the course of studying and testing, must get application in the power system in the future. In case of adopting ota and otv, namely should be putting and is being protected near the equipment.After the optical signals of ota and otv are input in the integrated device here and changes into an electric signal, what is on one hand uses as being protected calculation is judged ; As measurement amount on the other hand, send to the top management room through the network. Can to protect operation of equipment control order send this integrated device to through network from top management room, therefore the integrated device carries out the operation of the circuit breaker. The university of Tianjin put forward protecting,controlled , measured , communication integration in 1992, develop based on tms320c25 digital signal processor (dsp ) first protecting , control , measure , the integrated device of data communication.4)IntelligentIn recent years, if artificial intelligence technology neural network, hereditary algorithm, evolve plan , fuzzy logic ,etc. get application in power system all field, the research that is used in the field of relay protection has already begun too. Neural network one non-linear method that shine upon, a lot of difficult to list equation or difficult in order to the complicated non-linear question that is solved, use the method of the neural network to be very easily solved .For example the short circuit of crossing the resistance of courseof emergence is a non-linear problem in transmit electricity in the systematic electric potential angle of both sides of line and lay cases, it is very difficult to make discrimination , trouble of position while being correct for distance to protect, is it work up or is it work up to refuse by mistake to lead to the fact; If use neural network method, through a large number of trouble training of sample, so long as sample centralized to fully consider various kinds of situations, can differentiate correctly while any trouble takes place. Other if hereditary algorithm , is it is it have is it solve complicated abilityof problem to asking unique their too to plan to evolve. Artificial intelligence the being method proper to is it can make it solve speed to be fast not to ask to combine. Can predict , the artificial intelligence technology must get application in the field of relay protection, in order to solve the problem difficult to solvewith the routine method.中文翻译:继电保护的现状与发展一、继电保护发展现状电力系统的飞速发展对继电保护不断提出新的要求，电子技术、计算机技术与通信技术的飞速发展又为继电保护技术的发展不断地注入了新的活力，因此，继电保护技术得天独厚，在40余年的时间里完成了发展的4个历史阶段。
(完整版)电气专业中英文对照翻译毕业设计论文
优秀论文审核通过未经允许切勿外传Chapter 3 Digital Electronics3.1 IntroductionA circuit that employs a numerical signal in its operation is classified as a digital circuitputers,pocket calculators, digital instruments, and numerical control (NC) equipment are common applications of digital circuits. Practically unlimited quantities of digital information can be processed in short periods of time electronically. With operational speed of prime importance in electronics today,digital circuits are used more frequently.In this chapter, digital circuit applications are discussed.There are many types of digital circuits that electronics, including logic circuits, flip-flop circuits, counting circuits, and many others. The first sections of this unit discuss the number systems that are basic to digital circuit understanding. The remainder of the chapter introduces some of the types of digital circuits and explains Boolean algebra as it is applied to logic circuits.3.2 Digital Number SystemsThe most common number system used today is the decimal system,in which 10 digits are used for counting. The number of digits in the systemis called its base (or radix).The decimal system，therefore，the counting process. The largest digit that can be used in a specific place or location is determined by the base of the system. In the decimal system the first position to the left of the decimal point is called the units place. Any digit from 0 to 9 can be used in this place.When number values greater than 9 are used,they must be expressed with two or more places.The next position to the left of the units place in a decimal system is the tens place.The number 99 is the largest digital value that can be expressed by two places in the decimal system.Each place added to the left extends the number system by a power of 10.Any number can be expressed as a sum of weighted place values.The decimal number 2583,for example, is expressed as (2×1000)+(5×100)+(8×10)+(3×1).The decimal number system is commonly used in our daily lives. Electronically, the binary system.Electronically,the value of 0 can be associated with a low-voltage value or no voltage. The number 1 can then be associated with a voltage value larger than 0. Binary systems that use these voltage values are said to , this chapter.The two operational states of a binary system,1 and 0,are natural circuit conditions. When a circuit is turned off or the off, or 0,state. An electrical circuit that the on，or 1,state. By using transistor or ICs，it is electronically possible to change states in less than a microsecond. Electronic devices make it possible to manipulate millions of 0s and is in a second and thus to process information quickly.The basic principles of numbering used in decimal numbers apply ingeneral to binary numbers.The base of the binary system is 2,meaning that only the digits 0 and 1 are used to express place value. The first place to the left of the binary point,or starting point，represents the units，or is,location. Places to the left of the binary point are the powers of 2.Some of the place values in base 2 are 2º=1,2¹=2,2²=4,2³=8,2⁴=16,25=32,and 26=64.When bases other than 10 are used,the numbers should example.The number 100₂(read“one,zero,zero, base 2”)is equivalent to 4 in base 10,or 410.Starting with the first digit to the left of the binary point,this number this method of conversion a binary number to an equivalent decimal number，write down the binary number first. Starting at the binary point，indicate the decimal equivalent for each binary place location where a 1 is indicated. For each 0 in the binary number leave a blank space or indicate a 0 ' Add the place values and then record the decimal equivalent.The conversion of a decimal number to a binary equivalent is achieved by repetitive steps of division by the number 2.When the quotient is even with no remainder,a 0 is recorded.When the quotient process continues until the quotient is 0.The binary equivalent consists of the remainder values in the order last to first.3.2.2 Binary-coded Decimal (BCD) Number SystemWhen large numbers are indicated by binary numbers，they are difficult to use. For this reason，the Binary-Coded Decimal(BCD) method of counting was devised. In this system four binary digits are used to represent each decimal digit.To illustrate this procedure，the number 105，is converted to a BCD number.In binary numbers，To apply the BCD conversion process，the base 10 number is first divided into digits according to place values.The number 10510 gives the digits 1-0-5.Converting each displayed by this process with only 12 binary numbers. The between each group of digits is important when displaying BCD numbers.The largest digit to be displayed by any group of BCD numbers is 9.Six digits of a number-coding group are not used at all in this system.Because of this, the octal (base 8) and the binary form but usually display them in BCD,octal,or a base 8 system is 7. The place values starting at the left of the octal point are the powers of eight: 80=1,81=8,82=64,83=512,84=4096,and so on.The process of converting an octal number to a decimal number is the same as that used in the binary-to-decimal conversion process. In this method, equivalent decimal is 25810.Converting an octal number to an equivalent binary number is similar to the BCD conversion process. The octal number is first divided into digits according to place value. Each octal digit is then converted into an equivalent binary number using only three digits.Converting a decimal number to an octal number is a process of repetitive division by the number 8.After the quotient determined，the remainder is brought down as the place value.When the quotient is even with no remainder，a 0 is transferred to the place position.The number for converting 409810 to base 8 is 100028.Converting a binary number to an octal number is an importantconversion process of digital circuits. Binary numbers are first processed at a very output circuit then accepts this signal and converts it to an octal signal displayed on a readout device.must first be divided into groups of three，starting at the octal point.Each binary group is then converted into an equivalent octal number.These numbers are then combined，while remaining in their same respective places，to represent the equivalent octal number.3.2.4 Hexadecimal Number SystemThe digital systems to process large number values.The base of this system is 16，which means that the largest number used in a place is 15.Digits used by this system are the numbers 0-9 and the letters A-F. The letters A-P are used to denote the digits 10-15，respectively. The place values to the left of the .The process of changing a proper digital order.The place values，or powers of the base，are then positioned under the respective digits in step 2.In step 3，the value of each digit is recorded. The values in steps 2 and 3 are then multiplied together and added. The sum gives the decimal equivalent value of a . Initially，the converted to a binary number using four digits per group. The binary group is combined to form the equivalent binary number.The conversion of a decimal number to a ，as with other number systems. In this procedure the division is by 16 and remainders can be as large as 15.Converting a binary number to a groups of four digits，starting at the converted to a digital circuit-design applications binary signals arefar superior to those of the octal，decimal，or be processed very easily through electronic circuitry，since they can be represented by two stable states of operation. These states can be easily defined as on or off, 1 or 0，up or down，voltage or no voltage，right or left，or any other two-condition states. There must be no in-between state.The symbols used to define the operational state of a binary system are very important.In positive binary logic，the state of voltage，on，true，or a letter designation (such as A ) is used to denote the operational state 1 .No voltage，off，false，and the letter A are commonly used to denote the 0 condition. A circuit can be set to either state and will remain in that state until it is caused to change conditions.Any electronic device that can be set in one of two operational states or conditions by an outside signal is said to be bistable. Relays，lamps，switches，transistors, diodes and ICs may be used for this purpose. A bistable device .By using many of these devices，it is possible to build an electronic circuit that will make decisions based upon the applied input signals. The output of this circuit is a decision based upon the operational conditions of the input. Since the application of bistable devices in digital circuits makes logical decisions，they are commonly called binary logic circuits.If we were to draw a circuit diagram for such a system，including all the resistors，diodes，transistors and interconnections，we would face an overwhelming task, and an unnecessary one.Anyone who read the circuit diagram would in their mind group the components into standard circuits and think in terms of the" system" functions of the individual gates. Forthis reason，we design and draw digital circuit with standard logic symbols. Three basic circuits of this type are used to make simple logic decisions.These are the AND circuit, OR circuit, and the NOT circuit.Electronic circuits designed to perform logic functions are called gates.This term refers to the capability of a circuit to pass or block specific digital signals.The logic-gate symbols are shown in Fig.3-1.The small circle at the output of NOT gate indicates the inversion of the signal. Mathematically，this action is described as A=.Thus without the small circle，the rectangle would represent an amplifier (or buffer) with a gain of unity.An AND gate the 1 state simultaneously，then there will be a 1 at the output.The AND gate in Fig. 3-1 produces only a 1 out-put when A and B are both 1. Mathematically，this action is described as A·B=C. This expression shows the multiplication operation. An OR gate Fig.3-1 produces a when either or both inputs are l.Mathematically，this action is described as A+B=C. This expression shows OR addition. This gate is used to make logic decisions of whether or not a 1 appears at either input.An IF-THEN type of sentence is often used to describe the basic operation of a logic state.For example，if the inputs applied to an AND gate are all 1，then the output will be 1 .If a 1 is applied to any input of an OR gate，then the output will be 1 .If an input is applied to a NOT gate，then the output will be the opposite or inverse.The logic gate symbols in Fig. 3-1 show only the input and output connections. The actual gates，when wired into a digital circuit, would pin 14 and 7.3.4 Combination Logic GatesWhen a NOT gate is combined with an AND gate or an OR gate，it iscalled a combination logic gate. A NOT-AND gate is called a NAND gate，which is an inverted AND gate. Mathematically the operation of a NAND gate is A·B=. A combination NOT-OR ，or NOR，gate produces a negation of the OR function.Mathematically the operation of a NOR gate is A+B=.A 1 appears at the output only when A is 0 and B is 0.The logic symbols are shown in Fig. 3-3.The bar over C denotes the inversion，or negative function，of the gate.The logic gates discussed .In actual digital electronic applications，solid-state components are ordinarily used to accomplish gate functions.Boolean algebra is a special form of algebra that was designed to show the relationships of logic operations.Thin form of algebra is ideally suited for analysis and design of binary logic systems.Through the use of Boolean algebra，it is possible to write mathematical expressions that describe specific logic functions.Boolean expressions are more meaningful than complex word statements or or elaborate truth tables.The laws that apply to Boolean algebra are used to simplify complex expressions. Through this type of operation it may be possible to reduce the number of logic gates needed to achieve a specific function before the circuits are designed.In Boolean algebra the variables of an equation are assigned by letters of the alphabet.Each variable then exists in states of 1 or 0 according to its condition.The 1，or true state，is normally represented by a single letter such as A，B or C.The opposite state or condition is then described as 0，or false，and is represented by or A’.This is described as NOT A，A negated，or A complemented.Boolean algebra is somewhat different from conventional algebra withrespect to mathematical operations.The Boolean operations are expressed as follows:Multiplication:A AND B，AB，,A·BOR addition:A OR B .A+BNegation，or complementing:NOT A，，A’Assume that a digital logic circuit only C is on by itself or when A，B and C are all on expression describes the desired output. Eight (23) different combinations of A，B，and C exist in this expression because there are three，inputs. Only two of those combinations should cause a signal that will actuate the output. When a variable is not on (0)，it is expressed as a negated letter. The original statement is expressed as follows: With A，B，and C on or with A off, B off, and C on ，an output (X）will occur:ABC+C=XA truth table illustrates if this expression is achieved or not.Table 3-1 shows a truth table for this equation. First，ABC is determined by multiplying the three inputs together.A 1 appears only when the A，B，and C inputs are all 1.Next the negated inputs A andB are determined.Then the products of inputs C，A，and B are listed.The next column shows the addition of ABC and C.The output of this equation shows that output 1 is produced only when C is 1 or when ABC is 1.A logic circuit to accomplish this Boolean expression is shown in Fig. 3-4.Initially the equation is analyzed to determine its primary operational function.Step1 shows the original equation.The primary function is addition，since it influences all parts of the equation in some way.Step 2 shows the primary function changed to a logic gate diagram.Step 3 showsthe branch parts of the equation expressed by logic diagram，with AND gates used to combine terms.Step 4 completes the process by connecting all inputs together.The circles at inputs，of the lower AND gate are used to achieve the negative function of these branch parts.The general rules for changing a Boolean equation into a logic circuit diagram are very similar to those outlined.Initially the original equation must be analyzed for its primary mathematical function.This is then changed into a gate diagram that is inputted by branch parts of the equation.Each branch operation is then analyzed and expressed in gate form.The process continues until all branches are completely expressed in diagram formmon inputs are then connected together.3.5 Timing and Storage ElementsDigital electronics involves a number of items that are not classified as gates.Circuits or devices of this type the operation of a system.Included in this system are such things as timing devices，storage elements，counters，decoders，memory，and registers.Truth tables symbols，operational characteristics，and applications of these items will be presented an IC chip. The internal construction of the chip cannot be effectively altered. Operation is controlled by the application of an external signal to the input. As a rule，very little work can be done to control operation other than altering the input signal.The logic circuits in Fig. 3-4 are combinational circuit because the output responds immediately to the inputs and there is no memory. When memory is a part of a logic circuit，the system is called sequential circuit because its output depends on the input plus its an input signal isapplied.A bistable multivibrator，in the strict sense，is a flip-flop. When it is turned on，it assumes a particular operational state. It does not change states until the input is altered.A flip-flop opposite polarity.Two inputs are usually needed to alter the state of a flip-flop. A variety of names are used for the inputs.These vary a great deal between different flip-flops.1. R-S flip-flopsFig.3-5 shows logic circuit construction of an R-S flip-flop. It is constructed from two NAND gates. The output of each NAND provides one of the inputs for the other NAND. R stands for the reset input and S represents the set input.The truth table and logic symbol are shown in Fig. 3-6.Notice that the truth table is somewhat more complex than that of a gate. It shows, for example，the applied input, previous output，and resulting output.To understand the operation of an R-S flip-flop，we must first look at the previous outputs.This is the status of the output before a change is applied to the input. The first four items of the previous outputs are Q=1 and =0. The second four states this case of the input to NANDS is 0 and that is 0，which implies that both inputs to NANDR are 1.By symmetry，the logic circuit will also stable with Q0 and 1.If now R momentarily becomes 0，the output of NANDR，，will rise to resulting in NANDS be realized by a 0 at S.The outputs Q and are unpredictable when the inputs R and S are 0 states.This case is not allowed.Seldom would individual gates be used to construct a flip-flop，rather than one of the special types for the flip-flop packages on a single chipwould be used by a designer.A variety of different flip-flops are used in digital electronic systems today. In general，each flip-flop type R-S-T flip-flop for example .is a triggered R-S flip-flop. It will not change states when the R and S inputs assume a value until a trigger pulse is applied. This would permit a large number of flip-flops to change states all at the same time. Fig. 3-7 shows the logic circuit construction. The truth table and logic symbol are shown in Fig. 3-8. The R and S input are thus active when the signal at the gate input (T) is 1 .Normally，such timing，or synchronizing，signals are distributed throughout a digital system by clock pulses，as shown in Fig. 3-9.The symmetrical clock signal provides two times each period.The circuit can be designed to trigger at the leading or trailing edge of the clock. The logic symbols for edge trigger flip-flops are shown in Fig.3-10.2. J-K flip-flopsAnother very important flip-flop unpredictable output state. The J and K inputs addition to this，J-K flip-flops may employ preset and preclear functions. This is used to establish sequential timing operations. Fig.3-11 shows the logic symbol and truth table of a J-K flip-flop.3. 5. 2 CountersA flip-flop be used in switching operations，and it can count pulses.A series of interconnected flip-flops is generally called a register.Each register can store one binary digit or bit of data. Several flip-flops connected form a counter. Counting is a fundamental digital electronic function.For an electronic circuit to count，a number of things must beachieved. Basically，the circuit must be supplied with some form of data or information that is suitable for processing. Typically，electrical pulses that turn on and off are applied to the input of a counter. These pulses must initiate a state change in the circuit when they are received. The circuit must also be able to recognize where it is in counting sequence at any particular time. This requires some form of memory. The counter must also be able to respond to the next number in the sequence. In digital electronic systems flip-flops are primarily used to achieve counting. This type of device is capable of changing states when a pulse is applied，output pulse.There are several types of counters used in digital circuitry today.Probably the most common of these is the binary counter.This particular counter is designed to process two-state or binary information. J-K flip-flops are commonly used in binary counters.Refer now to the single J-K flip-flop of Fig. 3-11 .In its toggle state，this flip-flop is capable of achieving counting. First，assume that the flip-flop is in its reset state. This would cause Q to be 0 and Q to be 1 .Normally，we are concerned only with Q output in counting operations. The flip-flop is now connected for operation in the toggle mode. J and K must both be made the 1 state. When a pulse is applied to the T，or clock，input，Q changes to 1.This means that with one pulse applied，a 1 is generated in the output. The flip-flop the next pulse arrives，Q resets，or changes to 0. Essentially，this means that two input pulses produce only one output pulse. This is a divide-by-two function.For binary numbers，counting is achieved by a number of divide-by-two flip-flops.To count more than one pulse，additional flip-flops must be employed. For each flip-flop added to the counter，its capacity is increased by the power of 2. With one flip-flop the maximum count was 20，or 1 .For two flip-flops it would count two places，such as 20 and 21.This would reach a count of 3 or a binary number of 11.The count would be 00，01，10，and 11. The counter would then clear and return to 00. In effect, this counts four state changes. Three flip-flops would count three places，or 20，21，and 22.This would permit a total count of eight state changes.The binary values are 000，001，010，011，100，101，110 and 111.The maximum count is seven，or 111 .Four flip-flops would count four places，or 20，21，22，and 23.The total count would make 16 state changes. The maximum count would be 15，or the binary number 1111.Each additional flip-flop would cause this to increase one binary place.河南理工大学电气工程及其自动化专业中英双语对照翻译。
电气专业毕业设计英文文献
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电子电气专业毕业外文翻译
DC Switching Power Supply Protection TechnologyAbstract: The DC switching power supply protection system, protection system design principles and machine protection measures, an analysis of switching power supply in the range of protected characteristics and its design methodology, introduced a number of practical protection circuit.Keywords: switching power supply protection circuit system designA、IntroductionDC switching regulator used in the price of more expensive high-power switching devices, the control circuit is also more complex, In addition, the load switching regulators are generally used a large number of highly integrated electronic systems installed devices. Transistors and integrated device tolerance electricity, less heat shocks. Switching Regulators therefore should take into account the protection of voltage regulators and load their own safety. Many different types of circuit protection, polarity protection, introduced here, the program protection, over-current protection, over-voltage protection, under-voltage protection and over-temperature protection circuit. Usually chosen to be some combination of protection, constitutes a complete protection system.B、Polarity protectionDC switching regulator input is generally not regulated DC power supply. Operating errors or accidents as a result of the situation will take its wrong polarity; switching power supply will be damaged. Polarity protection purposes, is to make the switching regulator only when the correct polarity is not connected to DC power supply regulator to work at. Connecting a single device can achieve power polarity protection. Since the diode D to flow through switching regulator input total current, this circuit applied in a low-power switching regulator more suitable. Power in the larger occasion,while the polarity protection circuit as a procedure to protect a link, save the power required for polarity protection diodes, power consumption will be reduced. In order to easy to operate, make it easier to identify the correct polarity or not, collect the next light.C、Procedures to protectSwitching power supply circuit is rather complicated, basically can be divided into low-power and high-power part of the control part of the switch. Switch is a high-power transistors, for the protection of the transistor switch is turned on or off power safety, we must first modulator, amplifier and other low-power control circuit. To this end, the boot to ensure the correct procedures. Switching Regulators generally take the input of a small inductor, the input filter capacitor. Moment in the boot, filter capacitor will flow a lot of surge current, the surge current can be several times more than the normal input current. Such a large surge current may contact the general power switch or relay contact melting, and the input fuse. In addition, the capacitor surge current will damage to shorten the life span of premature damage. To this end, the boot should be access to a current limiting resistor, through the current limiting resistor to capacitor charging. In order not to make the current limiting resistor excessive power consumption, thus affecting the normal switching regulator, and the transient process in the boot after a short period then automatically relays it to DC power supply directly to the switching regulator power supply. This circuit switching regulator called a "soft start" circuit.Switching regulator control circuit of the logic components required or op-amp auxiliary power supply. To this end, the auxiliary power supply must be in the switch circuit. This control circuit can be used to ensure the boot. Normal boot process is: to identify the polarity of input power, voltage protection procedures → boot → auxiliary power supply circuit and through current limiting resis tor R of the switching regulator input capacitor C →charge modulation switching regulator circuit, → short-circuit current limiting resistor stability switching regulator.In the switching regulator, the machines just because the output capacitance, and charge to the rated output voltage value of the need for a certain period of time. During this time, sampling the output amplifier with low input voltage sampling, closed-loop regulation characteristics of the system will force the switching of the transistor conduction time lengthened, so that switching transistor during this period will tend to continuous conduction, and easily damaged. To this end, the requirements of this paragraph in the boot time, the switch to switch the output modulation circuit transistor base drive signal of the pulse width modulation, can guarantee the switching transistor by the cut-off switches are becoming more and more normal state, therefore the protection of the setting up of a boot to tie in with the soft start.D、Over-current protectionWhen the load short-circuit, overload control circuit failure or unforeseen circumstances, such as would cause the flow of switching voltage regulator transistor current is too large, so that increased power tubes, fever, if there is no over-current protection device, high power switching transistor may be damaged. Therefore, the switching regulator in the over-current protection is commonly used. The most economical way is to use simple fuse. As a result of the heat capacity of small transistors, general fuse protection in general can not play a role in the rapid fuse common fuse. This method has the advantage of the protection of vulnerable, but it needs to switch transistor in accordance with specific security requirements of the work area to select the fuse specifications. This disadvantage is over-current protection measures brought about by the inconvenience of frequent replacement of fuses.Linear voltage regulator commonly used in the protection and currentlimiting to protect the cut-off in the switching regulator can be applied. However, according to the characteristics of switching regulators, the protection circuit can not directly control the output transistor switches, and over current protection must be converted to pulse output commands to control the modulator to protect the transistor switch. In order to achieve over-current protection are generally required sampling resistor in series in the circuit, this will affect the efficiency of power supply, so more for low-power switching regulator of occasions. In the high-power switching power supply, by taking into account the power consumption should be avoided as far as possible access to the sampling resistor. Therefore, there will usually be converted to over-current protection, and under-voltage protection.E、Over-voltage protectionSwitching regulator's input over-voltage protection, including over-voltage protection and output over-voltage protection. Switching regulator is not used in DC power supply voltage regulator and rectifier, such as battery voltage, if too high, so switching regulator is not working properly, or even damage to internal devices, therefore, it is necessary to use the input over-voltage protection circuit. Using transistors and relays protection circuit.In the circuit, when the input DC power supply voltage higher than the voltage regulator diode breakdown voltage value, the breakdown voltage regulator tube, a current flowing through resistor R, so that V turn-on transistor, relay, normally closed contact off open, cut off the input. Voltage regulator voltage regulator which controls the value of Vs. = Earwax-UBE. The polarity of input power with the input protection circuit can be combined with over-voltage protection, polarity protection constitute a differential circuit and over voltage protection.Output over-voltage protection switching power supply is essential. In particular, for the 5V output of the switching regulator, it is a lot of load on a high level of integration of the logic device. If at work, switching regulator sudden damage to the switch transistor, the output potential may be increased immediately to the importation of non-regulated DC power supply voltage value, causing great loss instantaneous. Commonly used method is short-circuit protection thirsted. The simplest over-voltage protection circuit. When the output voltage is too high, the regulator tube breakdown triggered thirstier turn-on, the output short-circuit, resulting in over-current through the fuse or circuit protective device to cut off the input to protect the load. This circuit is equivalent to the response time of the opening time of thirstier is about 5 ~ 10μs. The disadvantage is that its action is fixed voltage, temperature coefficient, and action points of instability. In addition, there is a voltage regulator control parameters of the discrete, model over-voltage start-up the same but has different values, difficult to debug. Esc a sudden increase in output voltage, transistors V1, V2 conduction, the thruster conduction. Reference voltage Vs. by type.F、Under-voltage protectionOutput voltage below the value to reflect the input DC power supply, switching regulator output load internal or unusual occurrence. Input DC power supply voltage drops below the specified value would result in switching regulator output voltage drops, the input current increases, not only endanger the switching transistor, but also endanger the input power. Therefore, in order to set up due to voltage protection. Due to simple voltage protection.When no voltage regulator input normal, ZD breakdown voltage regulator tube, transistors V conduction, the relay action, contact pull-in, power-switching regulator. When the input below the minimum allowable voltage value, the regulator tube ZD barrier, V cut-off, contact Kai-hop,switching regulator can not work. Internal switching regulator, as the control switch transistor circuit disorders or failure will decrease the output voltage; load short-circuit output voltage will also decline.Especially in the reversed-phase step-up or step-up switching regulator DC voltage of the protection due to over-current protection with closely related and therefore more important. Implementation of Switching Regulators in the termination of the output voltage comparators.Normally, there is no comparator output, once the voltage drops below the allowable value in the comparator on the flip, drive alarm circuit; also fed back to the switching regulator control circuit, so that switching transistor cut-off or cut off the input power.G、Over-temperature protectionSwitching regulator and the high level of integration of light-weight small volume, with its unit volume greatly increased the power density, power supply components to its work within the requirements of the ambient temperature is also a corresponding increase. Otherwise, the circuit performance will deteriorate premature component failure. Therefore, in high-power switching regulator should be set up over-temperature protection.Relays used to detect the temperature inside the power supply temperature, when the internally generated power supply overheating, the temperature of the relay on the action, so that whole circuit in a warning alarm, and the realization of the power supply over-temperature protection. Temperature relay can be placed in the vicinity of the switching transistor, the general high-power tube shell to allow the maximum temperature is 75 ℃, adjust the temperature setting to 60 ℃. When the shell after the temperature exceeds the allowable value to cut off electrical relay on the switch protection. Semiconductor switching device thermal "hot thirstier," in the over-temperature protection, played an important role. It can be used asdirected circuit temperature. Under the control of p-hot-gate thirstier (TT102) characteristics, by RT value to determine the temperature of the device turn-on, RT greater the temperature the lower the turn-on. When placed near the power switching transistor or power device, it will be able to play the role of temperature instructions. When the power control the temperature of the shell or the internal device temperature exceeds the allowed value, the heat conduction thirstier on, so that LED warning light. If the opt coupler with, would enable the whole circuit alarm action to protect the switching regulator. It can also be used as a power transistor as the over-temperature protection, crystal switch the base current by n-type gate control thirstier TT201 thermal bypass, cut-off switch to cut off the collector current to prevent overheating.I、ConclusionDiscussed above in the switching regulator of a variety of conservation, and introduces a number of specific ways to achieve. Of a given switching power supply is concerned, but also protection from the whole to consider the following points:1) The switching regulator used in the switching transistor in the DC security restrictions on the work of regional work. The transistor switches selected by the manual available transistors get DC safe working area. According to the maximum collector current to determine the input value of over-current protection. However, the instantaneous maximum value should be converted to the average current. At rated output current and output voltage conditions, the switch of the dynamic load line does not exceed a safe working area DC maximum input voltage, input over-voltage protection is the voltage value.2)The switching regulator output limit given by the technical indicators within. Work within the required temperature range, the switching regulator's output voltage, the lower limit of the output is off, due to thevoltage value of voltage protection. Over-current protection can be based on the maximum output current to determine. False alarm in order not to protect the value of a certain margin to remain appropriate.3)From the above two methods to determine the protection after the power supply device in accordance with the needs of measures to determine the alarm. Measures the general alarm sound and light alarm two police. Voice of the police applied to more complex machines, power supply parts and do not stand out in a place, it can give staff an effective warning of failure; optical Police instructions can be eye-catching and fault alarm and pointed out that the fault location and type. Protection measures should be protected as to determine the location. In the high-power, multi-channel power supply, always paying, DC circuit breakers, relays, etc. high-sensitivity auto-protection measures, to cut off the input power supply to stop working the system from damage. Through the logic control circuit to make the appropriate program cut-off switch transistor is sensitive it is convenient and economic. This eliminated large, long response time, the price of your high-power relay or circuit breaker.4) The power of putting in the protection circuit will be affected after the reliability of the system, for which want to protect the reliability of the circuit itself is higher in order to improve the reliability of the entire power system, thereby increasing its own power supply MTBF. This requires the protection of strict logic, the circuit is simple, at least components, In addition to the protection circuit should also be considered a failure of maintenance of their difficulty and their power to protect the damage.Therefore, we must be comprehensive and systematic consideration of a variety of switching power supply protection measures to ensure the normal operation of switching power supplies and high-efficiency and high reliability.直流开关稳压电源的保护技术摘要：讨论了直流开关稳压电源的保护系统,提出保护系统设计的原则和整机保护的措施，分析了开关稳压电源中的各种保护的特点及其设计方法,介绍了几种实用保护电路。
一篇电气专业英语文献与翻译
The Load Estimation and Power Tracking Integrated Control Strategy for Dual-Sides Controlled LCC Compensated WirelessCharging SystemABSTRACT In this paper, the wireless power transfer (WPT) system with dynamic loads such as batteries is studied comprehensively. An integrated control technology of load estimation and power tracking of LCC compensated is proposed, which realizes load estimation, mode judgment and charging control at the transmitter, and standard load setting and decoupling control at the receiver. Based on the inflfluence of reflflection impedance on the output current of the inverter, a method of identifying coupling coeffificient and equivalent load is proposed and a mathematical model is established. Receiver controller provides standard reference load for load estimation. Transmitter controller judges battery status according to the estimation of equivalent load and adopts double closed-loop control to regulate power and current. Receiver decouples control when battery charging voltage reaches the threshold, and providing mode conversion sign for transmitter controller to realize constant current (CC) and constant voltage (CV) charging of battery.The Dual-sides integrated control scheme has no data communication between transmitter and receiver, so it can control independently, which reduces the complexity of the system and is suitable for different charging modes. The proposed controller is more effificient as it maintains a track current, and dynamically alters the pick-up characteristics to suit the load demand. Finally, the simulation and experimental results validate the feasibility of proposed control method, which realizes the estimation of the load and CC/CV charging of the battery. The proposed WPT system achieved the effificiency at 91.16% while delivering 2 kW to the load with a vertical air gap of 150 mm.INDEX TERMS Wireless power transfer, integrated control, load estimation, constant current/voltage charging, LCC compensation, phase shift control.Wireless Power Transmission (WPT) or Contactless Power Transmission (CPT) achieves the power transmission without physical connection, which makes up for the shortcomings of traditional power transmission methods . Wireless charging will promote the development of electric vehicles (EVs), because it provides more convenient, reliable and safer charging options than conductive charging . There are many research fields in WPT for EVs, especially the WPT system is sensitive to coupling coefficient, air gap, resonant frequency, and load change, which makes it hard for There are many research fields in WPT for EVs, especially the WPT system issensitive to coupling coefficient, air gap,resonant frequency, and load change, which makes it hard for robust control, and most scholars focus on the steady state of the WPT systems .When the resonant frequency, position, parameters and load of the wireless charging system change, which result in a higher volt-ampere rating and lower power transfer efficiency. Therefore, resonant compensation is an important part at the transmitter and receiver of the system. Different compensation topologies have been proposed and implemented to tune the two coils working at a resonant frequency in a wide range of applications. there are four basic compensation topologies, namely Series-Series (SS), SeriesParallel (SP), Parallel-Series (PS) and Parallel-Parallel (PP),are widely adopted for EV applications.Many other novel compensation topologies are also used to improve the power transfer efficiency and to simplify the control of WPT systems. Literatures show that LCL topology and series LC topology are the commonly used primary compensation networks for WPT. Compared with series LC, LCL performs better in power conversion efficiency over the full range of coupling and loading imposed, and its constant current source characteristic make its closed-loop control implementation easier. More advantageous compensation topologies are put forward in . The double-sided LCC compensation topology is outstanding since not only is its resonant frequency independent of coupling coefficient and load condition, but also its advantages of facilitating zero voltage switch (ZVS) or zero current switch (ZCS) of the inverter, realize CC charging at zero phase angle (ZPA) condition, increasing lateral misalignment tolerance, and improving WPT efficiency have been demonstrated.The other problem with WPT charger systems is implementing a charge process for EV batteries.Since batteries are considered to be varying loads during charging, the charge converter needs to regulate its output precisely to implement the constant current (CC) charge and constant voltage (CV) mode charge. Thus, meticulous control and tuning of the inverter is necessary since the load varies violently as the receive coil moves with the online EV.This adds to the control complexity and may reduce systematic reliability. In order to improve battery life and charging efficiency, it is necessary for a charger to provide accurate charge current and voltage through stable operations. In recent years, various control strategies have been studied to provide the required output currentorvoltagefortime-varyingloadsatdifferentcharging stages.The traditional control method is to use wireless communication to send the load state information to the transmitter controller to adjust the output power of the inverter to achieve CC/CV charging in . In order to simplify the control of an WPT charger system and avoid the above drawbacks of conventional control methods under wide variations of the load in implementing the CC/CV charge, some researchers have started to utilize the load-independent characteristics of the compensation topologies at their resonant frequencies proposes a design method which makes it possible to implement the CC/CV mode charge with minimum frequency variation during the entire charge process by using the load-independent characteristics of an WPT system under the ZPA condition without any additional switches. But, frequency variation may result in a bifurcation phenomenon,where the control ability and stability of the system are lost.In order to realize ZPA condition in the whole charging process, a switchablehybrid topology is proposed in [19], and [20]. CC and CV charging are realized in different compensation topologies. However, the addition of switches complicates the system, and changes in system parameters can also lead to instability.In[21], a new control technique was proposed, which only employs the controller at transmitting and and load identification approach to adjust charging voltage/current for SS and SP compensated WPT systems. The advantages are that dual-side wireless communication for real-time charging current/voltage adjustment is avoided as well as it is suitable for different charging modes. However, switching between two kinds of topologies is still needed. For the CC/CV charging control at constant frequency, some approaches employ a DC/DC converter to control the output current or voltage while the front-end converter operates at the resonant frequency to achieve the ZPA condition in [22] and [23]. However, this increases the component counts, losses and complexity. In [24], DC/DC converters are used for decoupling control rather than CC or CV charging.In [25]and [26], a single primary-side controller based on phase shift H-bridge inverter are proposed to adjust the charging current or charging voltage against various load, may make it hard for the High frequency inverter to achieve ZVS in full load range, especially with light load condition. Then, the primary-side control method that realizes CC/CV charging for battery is analyzed, which is the main contribution of this paper.The objective of this research is to study and develop a new integrated control strategy for load and power tracking that realizes CC/CV charging for LCC compensation through the double-loop controlled phase shift H-bridge inverter and load identification approach. The system adopts dual-side controller to avoid wireless communication, and the mathematical models of load estimation and mode judgment are derived by using the topological compensation characteristics of double-sided LCC. The working state of the battery is fed back to the transmitter controller by reflecting the impedance of the receiver, and the coupling coefficient of coils and load value are estimated.The transmitter judges the charging mode according to the estimated load, adjusts the output power of the inverter, and maintains CC/CV charging by phase-shifting control. In CC mode, the transmitter can transfer more power and prevents overloading. In CV mode, the output power can be adjusted according to the charging curve. The receiver control circuit adopts Buck-Boost structure. Different from the traditional impedance matching or CC/CV charging control mode, the receiver controller sets the standard reference value of load estimation control by impedance matching. Buck-Boost converter operates in switching mode during charging. When the charging voltage reaches the reference value, the switching action changes the reflection impedance and provides the mode conversion mark for the transmitter. Based on the feedback signal and the amount of transferred power, the controlling module continuously adjusts the transmitting coil current during the charging.The rest of the sections are organized as follows:Section II gives the system structure and basic theoretical analysis. Section III proposes the integrated control method of load estimation and power tracking, and then the double closed-loop PIcontroller of transmitter and receiver is designed. Section IV validates the proposed method with simulations and experiments.Finally,last section summarizes the conclusions drawn from the investigation.II. SYSTEM STRUCTURE AND THEORETICAL ANALYSISIn this section, the system structure and methodology for analyzing the WPT system are discussed. Then, basic output characteristics for LCC compensation are analyzed to propose the Integrated control method on the transmitting side and the receiving side.A.WIRELESS POWER TRANSMISSION SYSTEM TRUCTURE In this paper, the most widely used variable impedance load battery is taken as the research object.Charging characteristic curve of the battery is shown in Figure 1. Charging process includes CC/CV charging. In CC stage, the output power of the power supply increases with the increase of the battery terminal voltage, while the equivalent impedance of the battery increases with little change. In the CV stage, the charge current and power decrease,and the equivalent impedance of the battery increases rapidly.B. LOAD ESTIMATE AND MODEL RECOGNITION The transmitter controller measures Iinv to estimate the load and mutual inductance changes, and judges the working state of the receiver. The inverter operates at ZPA resonant frequency and the controller adjusts fro m 180◦ phase shift, which means that the minimum input voltage is applied to the transmitting coil. According to the requirement of the receiver, the power control unit uses phase shift control to adjust the It and VC to keep the CC and CV working modes at the receiver.The transmitter can control the power output according to the working mode of the receiver and the load demand. In order to achieve this function, the designed controller should be able to estimate mutual inductance and equivalent load, and then judge the charging mode of the receiving end. The control block diagram of load estimation and mode judgment strategy is shown in Figure 5. Where, Rx is the standard reference load of the receiver.CONCLUSION An integrated control method of load estimation and power tracking is proposed in this paper to achieve CC/CV charging.of LCC compensation WPT system. Firstly, through theoretical analysis, the LCC compensation topology can realize the charge of CC mode under ZPA condition, and get the relationship between the equivalent load and the current of the inverters. Then, a standard reference load is set at the receiver so that the transmitter can estimate the equivalent load by calculating the refection impedance and detecting the output current of the inverter. Finally, according to the estimated load value and the conversion mark given by the decoupling control of the receiver, the CC/CV charging for LCC compensation are realized by PI controlled phase shift full-bridge inverter. The simulation and experimental results validate the feasibility of the proposed control method for whole load changes. The proposed WPT system can achieve a high effenciency at 91.16% with a 20-cm air gap when delivering 0.2−2kW to the load in different charging stages.双边控制的LCC补偿型无线充电系统的负载估计与功率跟踪集成控制策略摘要本文对电池等动态负载下的无线电能传输（WPT）系统进行了全面的研究。
电力和配电系统之外文翻译(英)
Power Supply and Distribution SystemThe revolution of electric power system has brought a new big round construction,which is pushing the greater revolution of electric power technique along with the application of new technique and advanced equipment. Especially, the combination of the information technique and electric power technique, to great ex- tent, has improved reliability on electric quality and electric supply. The technical development decreases the cost on electric construction and drives innovation of electric network. On the basis of national and internatio- nal advanced electric knowledge, the dissertation introduces the research hotspot for present electric power sy- etem as following.Firstly, This dissertation introduces the building condition of distribution automation(DA), and brings forward two typical construction modes on DA construction, integrative mode and fission mode .It emphasize the DA structure under the condition of the fission mode and presents the system configuration, the main station scheme, the feeder scheme, the optimized communication scheme etc., which is for DA research reference. Secondly, as for the (DA) trouble measurement, position, isolation and resume, This dissertation analyzes the changes of pressure and current for line problem, gets math equation by educing phase short circuit and problem position under the condition of single-phase and works out equation and several parameter s U& , s I& and e I& table on problem . Itbrings out optimized isolation and resume plan, realizes auto isolation and network reconstruction, reduces the power off range and time and improves the reliability of electric power supply through problem self- diagnoses and self-analysis. It also introduces software flow and use for problem judgement and sets a model on network reconstruction and computer flow.Thirdly, electricity system state is estimated to be one of the key techniques in DA realization. The dissertation recommends the resolvent of bad measurement data and structure mistake on the ground of describing state estimate way. It also advances a practical test and judging way on topology mistake in state estimate about bad data test and abnormity in state estimate as well as the problem and effect on bad data from state measure to state estimate .As for real time monitor and control problem, the dissertation introduces a new way to solve them by electricity break and exceptional analysis.Fourthly, about the difficulty for building the model of load forecasting, big parameter scatter limit and something concerned, the dissertation introduces some parameters, eg. weather factor, date type and social environment effect based on analysis of routine load forecasting and means. It presents the way for electricity load forecasting founded on neural network(ANN),which has been tested it’s validity by example and made to be good practical effect.Fifthly, concerning the lack of concordant wave on preve nting concordant wave and non-power compensation and non-continuity on compensation, there is a topology structure of PWM main circuit and nonpower theory on active filter the waves technique and builds flat proof on the ground of Saber Designer and proves to be practical. Meanwhile, it analyzes and designs the way of non-power need of electric network tre- nds and decreasing line loss combined with DA, which have been tested its objective economic benefit throu- gh counting example.Sixthly, not only do the dissertation design a way founded on the magrginal electric price fitted to our present national electric power market with regards to future trends of electric power market in China and fair trade under the government surveillance, that is group competitio n in short-term trade under the way of grouped price and quantity harmony, but also puts forward combination arithmetic, math model of trading plan and safty economical restriction. It can solve the original contradiction between medium and long term contract price and short term competitive price with improvement on competitive percentage and cut down the unfair income difference of electric factory, at the same time, it can optimize the electric limit for all electric factories and reduce the total purchase charge of electric power from burthen curve of whole electric market network.The distribution network is an important link among the power system.Its neutral grounding mode and operation connects security and stability of the power system directly. At the same time, the problem about neutral grounding is associated with national conditions, natural environment, device fabrication and operation. For example, the activity situation of the thunder and lightning, insulating structure and the peripheral interference will influence the choice of neutral grounding mode Conversely, neutral grounding mode affects design, operation, debugs and developing. Generally in the system higher in grade in the voltage, the insulating expenses account for more sizable proportion at the total price of the equipment. It is very remarkable to bring the economic benefits by reducing the insulating level. Usually such system adopt the neutral directly grounding and adopt the autoreclosing to guarantee power supply reliability. On the contrary, the system which is lower in the voltage adopts neutral none grounding to raise power supply reliability. So it is an important subject to make use of new- type earth device to apply to the distribution network under considering the situation in such factors of various fields as power supply reliability, safety factor, over-voltage factor, the choice of relay protection, investment cost, etc.The main work of this paper is to research and choice the neutral grounding mode of the l0kV distribution network. The neutral grounding mode of the l0kV network mainly adopts none grounding, grounding by arc suppressing coil, grounding by reactance grounding and directlygrounding. The best grounding mode is confirmed through the technology comparison. It can help the network run in safety and limit the earth electric arc by using auto-tracking compensate device and using the line protection with the detection of the sensitive small ground current. The paper introduces and analyzes the characteristic of all kind of grounding modes about l0kV network at first. With the comparison with technological and economy, the conclusion is drawn that the improved arc suppressing coil grounding mode shows a very big development potential.Then, this paper researches and introduces some operation characteristics of the arc suppressing coil grounding mode of the l0kV distribution network. And then the paper put emphasis on how to extinguish the earth electric arc effectively by utilizing the resonance principle. This paper combines the development of domestic and international technology and innovative achievement, and introduces the computer earth protection and autotracking compensate device. It proves that the improved arc suppressing coil grounding mode have better operation characteristics in power supply reliability, personal security, security of equipment and interference of communication. The application of the arc suppressing coil grounding mode is also researched in this paper.Finally, the paper summarizes this topic research. As a result of the domination of the arc suppressing coil grounding mode, it should be morepopularized and applied in the distribution network in the future.The way of thinking, project and conclusions in this thesis have effect on the research to choose the neutral grounding mode not only in I0kV distribution network but also in other power system..The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, all costumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable. To improve the reliability of the power supply network, we must increase the investment cost of the network con- struction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic, between the investment and the loss by calculating the investment on power net and the loss brought from power-off. The thesis analyses on the economic and the reliable of the various line modes, according to the characteristics various line modes existed in the electric distribution net in foshan..First, the thesis introduces as the different line modes in the l0kV electricdistribution net and in some foreign countries. Making it clear tow to conduct analyzing on the line mode of the electric distribution net, and telling us how important and necessary that analyses are.Second, it turns to the necessity of calculating the number of optimization subsection, elaborating how it influences on the economy and reliability. Then by building up the calculation mode of the number of optimization subsection it introduces different power supply projects on the different line modes in brief. Third, it carries on the calculation and analyses towards the reliability and economy of the different line modes of electric distribution net, describing drafts according by the calculation. Then it makes analysis and discussion on the number of optimization subsection. At last, the article make conclusion on the economy and reliability of different line modes, as well as, its application situation. Accordion to the actual circumstance, the thesis puts forward the beneficial suggestion on the programming and construction of the l0kV electric distribution net in all areas in foshan. Providing the basic theories and beneficial guideline for the programming design of the lOkV electric distribution net and building up a solid net, reasonable layout, qualified safe and efficiently-worked electric distribution net.。
智能电网供配电系统中英文对照外文翻译文献
中英文对照资料外文翻译外文资料翻译Power supply system of high-rise building designAbstract: with the continuous development of city size, more and more high-rise buildings, therefore high-rise building electrical design to the designers had to face. In this paper, an engineering example, describes the electrical design of high-rise buildings and some of the more typical issues of universal significance, combined with the actual practice of an engineering solution to the problem described.Key words: high-rise building; electrical design; distribution; load calculation1 Project OverviewThe commercial complex project,with a total construction area of 405570m2,on the ground floor area of 272330m2, underground construction area of 133240m2, the main height of 99m. Project components are: two office buildings, construction area is 70800m2, 28 layers, the standard story is 3.2m.2 Load Calculation1) Load characteristics: electric load, much larger than the "national civil engineering technical measures" Large 120W/m2 indicators, especially in the electricity load more food, and different types of food and beverage catering different cultural backgrounds also high.2) the uncertainty of a large load, because the commercial real estate rents are often based on market demand, and constantly adjust the nature of the shops, making the load in the dynamic changes.3) There is no specification and technical measures in the different types of commercial projects refer to the detailed parameters of the shops, engineering design load calculation in the lack of data, in most cases to rely on staff with previous experience in engineering design calculations.Load the selection of parameters: for the above problems, the load calculation, the first developer of sales and good communication, to determine the form of layers of the forms and nature of floor area, which is calculated on the basis of electrical load basis; followed to determine parameter index within the unit area of shops is also very important and complex because there is no clear indicator of the specification can refer to; and different levels of economic development between cities is not balanced, power indices are also different; will be in the same city, different regions have different consumer groups .3) the need to factor in the choice: parameters determined, the need for load calculation. Need to factor commonly used method, the calculation will not repeat them. Need to explore is the need for coefficient selection, which in the current specifications, manuals and the "unified technical measures" is also not clear requirements, based on years of design experience that most end shops in the distribution or level within the household distribution box with case Kx generally take a while, in the calculation of the loop route to take 0.7 to 0.8, the distribution transformers in the substation calculations take 0.4 to 0.6.3 substations setLoad calculation based on the results of this project the total installed capacity of transformer 43400Kv.A, after repeated consultations with the power company, respectively, in the project in northern, central and southern three sections set the three buildings into three power substations, 1 # set 6 sets 2500Kv.A transformer substation, take the northern section of power supply; 2 # 4 1600Kv.A transformer substations located, plus 6 sets 2000Kv.A transformers, take the middle of the power supply, in addition to 5 Taiwan 10Kv.A high-pressure water chillers (total 4000Kv.A); 3 # substation located 2 units plus 2 units 1000Kv.A 2000Kv.A transformers, take the southern section of A, B twooffice supply. 10Kv power configuration of this project into two points, each at the two 10Kv lines, the power company under the provisions of 10Kv power capacity: maximum load per channel is about to 11000Kv.A, two is the 22000Kv.A, design # 1 , 3 # combination of a substation 10Kv, power line, with a total capacity of 21000Kv.A; 2 # substation transformers and 10Kv, 10Kv chillers sharing a power line, with a total capacity of 22400Kv.A. The design of the substation layout, in addition to meeting regulatory requirements, it also need to consider the high-pressure cabinets, transformers and low voltage power supply cabinet by order of arrangement, especially in low voltage distribution cabinet to feed the cable smooth and easy inspection duty problems are not seriously consider the construction of the cable crossing will cause more long detour, a waste of floor space, and convenient inspections and other issues【8】.4 small fire load power supplyIn the design of large commercial projects often encounter small fire load of electrical equipment and more dispersed distribution, if fed by a substation, a substation will be fed a lot of low-voltage low-current counter circuit breaking capacity circuit breaker and conductor of the dynamic and thermal stability in a certain extent. According to GB50045-1995 "fire protection design of tall buildings," rule "should be used in Fire Equipment dedicated power supply circuit, the power distribution equipment shall be provided with clear signs." Interpretation of the provisions of the power supply circuit means "from the low-voltage main distribution room (including the distribution of electrical room) to last a distribution box, and the general distribution lines should be strictly separated." In this design, the use of methods to increase the level of distribution, that is different from the substation bus segments, respectively, a fire fed a special circuit, set in place two distribution cabinets, distribution cabinets and then the resulting radial allocated to the end of the dual power to vote each box, so that not only meets the specification requirements for dedicated power supply circuit, but also to avoid feeding the substation level of many small current loop.5, the choice of circuit breaker and conductorCommercial real estate projects use the room as the uncertainty in the choice of circuit breakers and conductors must be considered in a certain margin to meet the needs caused by adjustment of the load changes. According to this characteristic, increased use in the design of the plug bus-powered, not only meet the requirements of large carrying capacity, and also allows the flexibility to increase supply and distribution, are reserved in each shaft in the plug-box backup in order to change, according to changes in upper and lower load, to adjust. For example: a bus is responsible for a shaft 1 to 3 layers of power, when a layer due to the change in capacity increases, while the 3-layer capacity is reduced, you can use a spare plug box layer off the 3-layer 1 layer capacity rationing . This level distribution in the substation, select the circuit breaker to choose the setting value when the circuit breaker to adjust to changes at the end to adjust the load setting value; in the bus and the transformer circuit breaker according to the choice of the general framework of values to select . For example: Route certain equipment capacity 530Kv, Kx take 0.7 to calculate current of 704A, select the frame circuit breaker is 1000A, tuning is 800A; current transformer for the 1000/50; bus carrying capacity for the 1000A, this road can meet the maximum 1000A current load requirements, even if there is adjustment, power distribution switches and circuit can not make big changes.6 layer distribution box setAccording to the division of layers of fire protection district, respectively numbered as A ~ K layers within the set level shaft for the retail lighting power distribution box, with one on one power supply shops in radial power. Should be noted that the forms of the complex layers of layers of fire partition, does not correspond to the lower, making some of shaft power in charge of the fire district at the same time, also responsible for the power supply adjacent to the fire district. At design time, using the principle of proximity, while also taking into account the burden of the whole trunk load conditions, so that each shaft as far as possible a more balanced load. PrerequisitesThe loop that you want to auto-tune must be in automatic mode. The loopoutput must be controlled by the execution of the PID instruction. Auto-tune will fail if the loop is in manual mode.Before initiating an auto-tune operation your process must be brought to a stable state which means that the PV has reached setpoint (or for a P type loop, a constant difference between PV and setpoint) and the output is not changing erratically.Ideally, the loop output value needs to be near the center of the control range when auto-tuning is started. The auto-tune procedure sets up an oscillation in the process by making small step changes in the loop output. If the loop output is close to either extreme of its control range, the step changes introduced in the auto-tune procedure may cause the output value to attempt to exceed the minimum or the maximum range limit.If this were to happen, it may result in the generation of an auto-tune error condition, and it will certainly result in the determination of less than near optimal suggested values.Auto-Hysteresis and Auto-DeviationThe hysteresis parameter specifies the excursion (plus or minus) from setpoint that the PV (process variable) is allowed to make without causing the relay controller to change the output. This value is used to minimize the effect of noise in the PV signal to more accurately determine the natural oscillation frequency of the process.If you select to automatically determine the hysteresis value, the PID Auto-Tuner will enter a hysteresis determination sequence. This sequence involves sampling the process variable for a period of time and then performing a standard deviation calculation on the sample results.In order to have a statistically meaningful sample, a set of at least 100 samples must be acquired. For a loop with a sample time of 200 msec, acquiring 100 samples takes 20 seconds. For loops with a longer sample time it will take longer. Even though 100 samples can be acquired in less than 20 seconds for loops with sample times less than 200 msec, the hysteresis determinationsequence always acquires samples for at least 20 seconds.Once all the samples have been acquired, the standard deviation for the sample set is calculated. The hysteresis value is defined to be two times the standard deviation. The calculated hysteresis value is written into the actual hysteresis field (AHYS) of the loop table.TipWhile the auto-hysteresis sequence is in progress, the normal PID calculation is not performed. Therefore, it is imperative that the process be in a stable state prior to initiating an auto-tune sequence. This will yield a better result for the hysteresis value and it will ensure that the process does not go out of control during the auto-hysteresis determination sequence.The deviation parameter specifies the desired peak-to-peak swing of the PV around the set point. If you select to automatically determine this value, the desired deviation of the PV is computed by multiplying the hysteresis value by 4.5. The output will be driven proportionally to induce this magnitude of oscillation in the process during auto-tuning.Auto-Tune SequenceThe auto-tuning sequence begins after the hysteresis and deviation values have been determined. The tuning process begins when the initial output step is applied to the loop output.This change in output value should cause a corresponding change in the value of the process variable. When the output change drives the PV away from setpoint far enough to exceed the hysteresis boundary a zero-crossing event is detected by the auto-tuner. Upon each zero crossing event the auto-tuner drives the output in the opposite direction.The tuner continues to sample the PV and waits for the next zero crossing event.A total of twelve zero-crossings are required to complete the sequence. The magnitude of the observed peak-to-peak PV values (peak error) and the rate at which zero-crossings occur are directly related to the dynamics of the process. Early in the auto-tuning process, the output step value is proportionally adjustedonce to induce subsequent peak-to-peak swings of the PV to more closely match the desired deviation amount. Once the adjustment is made, the new output step amount is written into the Actual Step Size field (ASTEP) of the loop table.The auto-tuning sequence will be terminated with an error, if the time between zero crossings exceeds the zero crossing watchdog interval time. The default value for the zero crossing watchdog interval time is two hours.Figure 1 shows the output and process variable behaviors during an auto-tuning sequence on a direct acting loop. The PID Tuning Control Panel was used to initiate and monitor the tuning sequence.Notice how the auto-tuner switches the output to cause the process (as evidenced by the PV value) to undergo small oscillations. The frequency and the amplitude of the PV oscillations are indicative of the process gain and natural frequency.7 public area distribution box setTaking into account the future needs of the business re-decoration of public areas must be reserved for power. Here the design needs to consider the following points:①question of how much reserve power, lighting and electricity, which according to GB50034-2004 "Architectural Lighting Design Standards" table of Article 6.1.3 and 6.1.8, commercial building lighting power density value, high-end supermarkets, business offices as 20W/m2, under the "decorative lighting included 50% of the total lighting power density calculation" requirements, using the reserved standard 40W/m2.②In order to facilitate the decoration in each partition set fire lighting in public areas and emergency lighting distribution box distribution box, in order to identify the electrical power distribution decoration cut-off point.③the staircase, storage rooms and other parts of the decoration does not need to do, set the power distribution circuit or a separate distribution box, try not to be reserved from the public area of electricity distribution board fed hardcover out.④control of lighting in public areas, the majority in two ways, namely,C-BUS control system or the BA system, the use of C-BUS has the advantage of more flexible control, each road can be fed out of control, adjustable light control; shortcomings is a higher cost. BA system control advantages of using low cost, simple control; disadvantage is that the exchanges and contacts for the three-phase, three-way control may be related both to open, or both, in the decoration of the contacts required to feed the power supply circuit diverge to avoid failure blackouts.Design of distribution box 8In the commercial real estate design, shop design is often only a meter box, and outlet route back to the needs of the user according to their second design, but the shops are difficult to resolve within the power supply fan coil units, air-conditioning system as a whole can not debug. The project approach is to add a circuit breaker in the meter box for the coil power supply, another way for users to use the second design, as shown below.User distribution box design9 distribution cabinet / box number and distribution circuitsLarge-scale projects are often low voltage distribution cabinet / box number, low-voltage circuits to feed the more often there will be cabinet / box number and line number duplication, resulting in the design and the future looks difficult maintenance and overhaul. The project has three 10Kv substations, 20 transformer, hundreds of low-voltage fed out of the closet, fed the circuit more. Accordance with the International Electrotechnical Commission (IEC) and the Chinese national standard requirements:①All the distribution number to be simple and clear, not too box and line numbers are not repeated.②number to simple and clear, not too long.③distinction between nature and type of load.④law was easy to find, make viewer at a glance. Based on the above requirements and on the ground, fire district and the underground construction industry form the different conditions, using two slightly different ways.Essential for the underground garage, uses a single comparison, also relatively fire district neat, according to fire district number, such as AL-BL-1 / 1, AP and APE, the meaning of the letters and numbers: AL on behalf of lighting distribution (AP on behalf of Power distribution box, APE on behalf of the emergency power distribution box); BI on behalf of the basement; 1 / 1 for partition 1, I fire box. Above ground is more complex, more fire district, and on the fire district does not correspond to the lower, according to shaft number is better, such as AL-1-A1, AP, and APE, letters and numbers mean: 1 represents a layer; A1 on behalf of A, No. 1 shaft fed a distribution box. Fed a low-voltage circuits, such as the number of uses: W3-6-AL-1-A1, W3-6) indicates that the route back to power supply transformer 3, 6, feed the power distribution cabinet, AL-1-A1, said the then the first loop of the distribution box for the AL-1-A1 and so on, and so on.10 ConclusionWith more and more complex commercial design projects, designers need to continually improve the design level, designed to make fine. These are only bits of the design in the business lessons learned, and the majority of designers want to communicate译文：浅谈高层建筑供配电系统设计摘要：随着城市规模的不断发展，高层建筑越来越多，因此，高层建筑电气设计就成为设计者不得不面对的问题。
电气自动化 中英文对照 外文翻译 毕业论文
外文翻译Linear Matrix Inequality-Based Fuzzy Control for Interior Permanent Magnet Synchronous Motor with integral sliding mode controlFaGuang Wang, Seung Kyu Park, Ho Kyun Ahn Department of Electrical Engineering, Changwon National University, Korea Abstract--Recently, interior permanent magnet synchronous motor (IPMSM) is widely used in various applications, such as electric vehicles and compressors. It has a high requirement in wide load variations, high speed condition, stability, providing a fast response and most important thing is that it can be applied easily and efficiently. However, the control of IPMSM is more difficult than surface permanent magnet synchronous motor (SPMSM) because its nonlinearity due to the non-zero daxis current which can be zero in SPSM but not IPMSM. In this paper, the IPMSM is controlled very efficient algorithm by using the combination of linear control and fuzzy control with linear models depending on certain operating points. The H linear matrix inequality (LMI) based integral sliding mode control is also used to ensure the robustness. The membership functions of this paper are easy to be determined and implemented easily. Index Terms--Fuzzy control, H control, integral sliding mode control, interior permanent magnet synchronous motor (IPMSM), linear matrix inequality.I. INTRODUCTIONFrom 1980s’, with the development of semiconductor, IPMSM supplied by converter source has been widely studied [1] [2]. The development of microcomputer made the vector control system of IPMSM well controlled by single chip. IPMSM possesses special features for adjustable-speed drives which distinguish it from otherclasses of ac machines, especially surface permanent magnet synchronous motor. The main criteria of high performance drives are fast and accurate speed response, quick recovery of speed from any disturbances and insensitivity to parameter variations [3]. In order to achieve high performances, the vector control of IPMSM drive is employed [4]-[6]. Control techniques become complicated due to the nonlinearities of the developed torque for non-zero value of d-axis current. Many researchers have focused their attention on forcing the daxis current equals to zero in the vector control of IPMSM drive, which essentially makes the motor model linear [4],[7]. However, in real-time the electromagnetic torque is non-linear in nature. In order to incorporate the nonlinearity in a practical IPMSM drive, acontrol technique known as maximum torque per ampere (MTPA) is devised which provides maximum torque with minimum stator current [3]. This MTPA strategy is very important from the limitation of IPMSM and inverter rating points of view, which optimizes the drive efficiency. The problem associated MTPA control technique is that its implementation in real time becomes complicated because there existsa complex relationship between d-axis and q-axis currents. Thus, oneof the main objectives of this paper is to make a new efficientcontrol method for IPMSM and its calculation easy and efficient. The LMI fuzzy H control has been applied and solved the nonlinearity of the IPMSM model to a set of linear model. To increase the robustness for disturbances, an ISMC technique is added to the H controller. By ISMC, the proposed controller gives performances of the H control system without disturbances which satisfy the matching condition. It has a good compatible with linear controllers. T-S fuzzy control [8]is based on the mathematical model which is the combination of local linear models depending on the operating points. Linear controllers are designed for each linear model and they are combined as a controller and make it possible to use linear control theories for nonlinear systems. Linear controls via parallel distributed compensation (PDC) and linear matrix inequality (LMI) is a most popular method considering the stability of the system with PDC [9].H LMI T-S fuzzy controller is considered as a practicalH controller which eliminates the effects of external disturbance below a prescribed level, so that a desired H control performancecan be guaranteed [10-12]. In this paper, the robustness of SMC [13]is added to the H LMI T-S fuzzy controller for the control of IPMSM. We can divide the disturbances in the IPMSM into two parts. Firstpart is that SMC can deal with and other part is dealt by H LMIfuzzy controller. By using ISMC, the robustness of SMC andH performance can be combined. Integral sliding mode control (ISMC) is a kind of SMC which has sliding mode dynamics with the same orderof the controlled system and can have the properties of the other control method.II. H T-S FUZZY CONTROL AND ISMCA. H T-S fuzzy controlConsider a nonlinear system as follows.x(t)=f (x)+g(x)u(t)+w(t) (1)where ||w(t)||≤Wb and Wb is the boundary of disturbance. Dependingon the operating points, the nonlinear system can be expressed as follows.The i-th model is that in the case z1(t) is Mi1 and …and z p(t) isMip ,(2)And H T-S fuzzy feedback controller is ui= -kiX(t) (3)where i=1,2, … ,r and Mij is the fuzzy set and r is the number of model rulesGiven a pair of (x(t),u(t)), the fuzzy systems are inferred as follows:where and μi(z(t)) is themembership for every fuzzy rule.From (1) we get(7)Take (6) into (7), we can get the closed loop systemequations.If we set A present the error boundary of every ruleand satisfy the following condition:In the same way we get:(9)Based on these, the approximation error can bebounded by matrix Ap and Bp . H control performance is:(10)where is the prescribed H norm. If we get theminimized for(10) we can make the effect of w(t) of (1) on x(t) is minimized.If consider the initial condition, the H norm (10) canbe modified as the following form:where P is some symmetric positive definite weighting matrix.The following result is given in [14]:Theorem 1: If system (1) is controlled by T-S fuzzy controller (6), and there is a positive definite matrix P such that（12）then the closed loop system is uniformly ultimately bounded (UUB) and H control performance (11) is guaranteed.It is not easy to obtain P and, fortunately, after small change of (12), it can be solved by LMI toolbox. So we need to do some changes.Assume Utilize the Schur complements for (12), we can get:（13）whereNow the problem changes to find the positive definite matrix L and F to satisfy the condition (13) and we can obtain k j at last. The (13) can be solved by LMI toolbox on computer easily.B. Sliding mode controlThe system (1) with input signal noise or disturbance d(t) is:（14）In the system (14), it can be considered that the disturbance is the summation of two different kinds of disturbancesw(t)=w1(t)+w2(t) (15)where w1(t) satisfies the following matching condition:（16）For the disturbance w1(t) , ISMC gives the desired response of the following system:（17）where x0 represents the state trajectory of the system with the disturbance w2(t) only under H T-S fuzzy control uo . Assume thatw(t) is bounded and that an upper bound can be found as（18）where wmax is a known positive scalar.For system (14), first redesign the control law to beu(t)=u0(t)+u1(t) （19）where is the ideal control defined in (6) and is designed to reject the perturbation term w1(t) .A sliding manifold is defined ass=s0 (x)+z(x) （20）where s,s0 (x), , which consists of two parts: the first part s0(x)is designed as a linear combination of the system states; the second part z introduces the integral term and will be determined below.（21）where initial condition z(0) is determined based on the requirements(0)=0. Different from the conventional design approach, the order of the motion equation in ISMC is equal to the order of the original system, rather than reduced by the dimension of the control input. As a result, robustness of the system can be guaranteed starting from the initial time instance.III. COMBINATION H T-S FUZZY CONTROL ANDINTEGRAL SMCThe mathematic model of an IPMSM in the d-q synchronously rotating reference frame for assumed sinusoidal stator excitation is given as [3]:（22）where p is the differential operator.The overall scheme of the H LMI T-S fuzzy control system is as follows.H LMI T-S fuzzy based ISMC controller designed as following steps. Step.1. utilize the equilibrium point to calculate the error system. System (22) can be presented by state form as:（23）where x1(t) =iq , x2(t) =id , x3(t) =wr ,u10(t) =vq andu20(t) =vd .Based on (23), a reference system can be given as:（24）where f means the required value.Then the following error dynamic system is derived.（25）where e(t)=x(t)-xf (t)Step.2. determine for membership function.For x1 minimum case:For x1 maximum case:For x2 minimum case:For x2 maximum case:The fuzzy rules are as the follows:Rule.1 x1 is minimal and x2 is minimal:M1(t) =E1(t)G1(t) （26）Rule.2 x1 is minimal and x2 is maximal:M2(t) =E1(t)G2(t) (27)Rule.3 x1 is maximal and x2 is minimal:M3(t) =E2(t)G1(t) (28)Rule.4 x1 is maximal and x2 is maximal:M4(t) =E2(t)G2(t) (29)Step.3. obtain the matrixes A and B.Equation (25) can be of the following form:and the value of ( x1lim , x2lim )is based on the rule1 to rule 4, it gets to be x1min,x1max,x2min and x2max .Step.4. calculate controller parameters K using LMI toolbox based on Theorem 1.By LMI, the error systemcontrol input is defined by (6) as（31）where k j is a 1by 3 matrix. Use inequality (13) and Matlab LMI toolbox to calculate out the parameters k j . So that, H T-S fuzzycontroller of the system is where u1 f and u2 fare reference inputs.Step.5. Design ISMC for system.Based on the SMC matching condition the system with disturbance is asfollows: （32）where d(t) is the noise or disturbance.The sliding surface is defined as:（33）x1r and x2r are required output values, x1n and x2n are states of nominalsystem: （34）Assume u1(t)=u10(t)+u1s(t) and u2(t)=u20(t)+u2s(t) .Derivate of slidingsurfaces are:（35）where e1n(t)=x1(t)x1n(t) , e2n(t)=x2(t)x2n(t) , un(t) is the nominalcontrol input and us1 and us2 are sliding control inputs.The sliding controller finally is given out as:（36）where d1max and d1max are the maximal absolute values of disturbance.IV. SIMULATION RESULTSUse the controller design process in above sections with the parameters of Tab.1. Simulation results are:TAB.1. IPMSM PARAMETERS.Fig.2. result of iq with parameter uncertainty and disturbance.Fig.3.result of id with parameter uncertainty and disturbance.Required output values are From the result of Fig.2and Fig.3, we can see that some kind of disturbance can not be solved only by H LMI T-S fuzzy. Combination with ISMC solves this perfectively.V. CONCLUSIONSThe Fuzzy LMI controller is used for IPMSM. It uses the linear models for each operating points. It is shown that only four operating points are enough for the proposed control method. The controller of this paper gives good control performance with only four membership functions which are determined easily. H fuzzy LMI solved theinitial big input for IPMSM from ISMC, while ISMC solved the problem of H fuzzy which is so dependent on fuzzy rules. The final results show that the combination control is efficient and perfect.具有积分滑模控制的内埋式永磁同步电动机基于线性矩阵不等式的模糊控制王发光, Seung Kyu Park, Ho Kyun Ahn韩国昌原国立大学电机工程学系近期摘要，内埋式永磁同步电动机被广泛的用于各种各样的应用中，例如电动汽车和压缩机。
供配电系统中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)POWER SUPPLY AND DISTRIBUTION SYSTEMABSTRACTThe basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, allcostumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable.To improve the reliability of the power supply network, we must increase the investment cost of the network construction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balancepoint to make the most economic,between the investment and the loss by calculating the investment on power net and the loss brought from power-off.KEYWARDS：power supply and distribution,power distribution reliability，reactive compensation,load distributionTEXTThe revolution of electric power system has brought a new big round construction,which is pushing the greater revolution of electric power technique along with the application of new technique and advanced equipment. Especially, the combination of the information technique and electric power technique, to great ex- tent, has improved reliability on electric quality and electric supply. The technical development decreases the cost on electric construction and drives innovation of electric network. On the basis of national and internatio- nal advanced electric knowledge, the dissertation introduces the research hotspot for present electric power sy- etem as following.Firstly, This dissertation introduces the building condition of distribution automation(DA), and brings forward two typical construction modes on DA construction, integrative mode and fission mode .It emphasize the DA structure under the condition of the fission mode and presents the system configuration, the main station scheme, the feeder scheme, the optimized communication scheme etc., which is for DA research reference.Secondly, as for the (DA) trouble measurement, position, isolation and resume, This dissertation analyzes the changes of pressure and current for line problem, gets math equation by educing phase short circuit and problem position under the condition of single-phase and works out equation and several parameter s U& , s I& and e I& table on problem . It brings out optimized isolation and resume plan, realizes auto isolation and network reconstruction, reduces the power off range and time and improves the reliability of electric power supply through problem self- diagnoses and self-analysis. It also introduces software flow and use for problem judgement and sets a model on network reconstruction and computer flow.Thirdly, electricity system state is estimated to be one of the key techniques in DA realization. The dissertation recommends the resolvent of bad measurement data and structure mistake on the ground of describing state estimate way. It also advances a practical test and judging way on topology mistake in state estimate about bad data test and abnormity in state estimate as well as the problem and effect on bad data from state measure to state estimate .As for real time monitor and control problem, the dissertation introduces a new way to solve them by electricity break and exceptional analysis, and the way has been tested in Weifang DA.Fourthly, about the difficulty for building the model of load forecasting, big parameter scatter limit and something concerned, the dissertation introduces some parameters, eg. weather factor, date type and social environment effect based on analysis of routine load forecasting and means. It presents the way for electricity load forecasting founded on neural network(ANN),which has been tested it’s validity by examp le and made to be good practical effect.Fifthly, concerning the lack of concordant wave on preve nting concordant wave and non-power compensation and non-continuity on compensation, there is a topology structure of PWM main circuit and nonpower theory on active filter the waves technique and builds flat proof on the ground of Saber Designer and proves to be practical. Meanwhile, it analyzes and designs the way of non-power need of electric network tre- nds and decreasing line loss combined with DA, which have been tested its objective economic benefit throu- gh counting example.Sixthly, not only do the dissertation design a way founded on the magrginal electric price fitted to our present national electric power market with regards to future trends of electric power market in China and fair trade under the government surveillance, that is group competitio n in short-term trade under the way of grouped price and quantityharmony, but also puts forward combination arithmetic, math model of trading plan and safty economical restriction. It can solve the original contradiction between medium and long term contract price and short term competitive price with improvement on competitive percentage and cut down the unfair income difference of electric factory, at the same time, it can optimize the electric limit for all electric factories and reduce the total purchase charge of electric power from burthen curve of whole electric market network.The distribution network is an important link among the power system. Its neutral grounding mode and operation connects security and stability of the power system directly. At the same time, the problem about neutral grounding is associated with national conditions, natural environment, device fabrication and operation. For example, the activity situation of the thunder and lightning, insulating structure and the peripheral interference will influence the choice of neutral grounding mode Conversely, neutral grounding mode affects design, operation, debugs and developing. Generally in the system higher in grade in the voltage, the insulating expenses account for more sizable proportion at the total price of the equipment. It is very remarkable to bring the economic benefits by reducing the insulating level. Usually such system adopt the neutral directly grounding and adopt the autoreclosing to guarantee power supply reliability. On the contrary, the system which is lower in the voltage adopts neutral none grounding to raise power supply reliability. So it is an important subject to make use of new- type earth device to apply to the distribution network under considering the situation in such factors of various fields as power supply reliability, safety factor, over-voltage factor, the choice of relay protection, investment cost, etc.The main work of this paper is to research and choice the neutral grounding mode of the l0kV distribution network. The neutral grounding mode of the l0kV network mainly adopts none grounding, grounding by arc suppressing coil, grounding by reactance grounding and directly grounding. The best grounding mode is confirmed through the technology comparison. It can help the network run in safety and limit the earth electric arc by using auto-tracking compensate device and using the line protection with the detection of the sensitive small ground current. The paper introduces and analyzes the characteristic of all kind of grounding modes about l0kV network at first. With the comparison with technological and economy, the conclusion is drawn that the improved arc suppressing coil grounding mode shows a very big development potential.Then, this paper researches and introduces some operation characteristics of the arc suppressing coil grounding mode of the l0kV distribution network. And then the paper putemphasis on how to extinguish the earth electric arc effectively by utilizing the resonance principle. This paper combines the development of domestic and international technology and innovative achievement, and introduces the computer earth protection and autotracking compensate device. It proves that the improved arc suppressing coil grounding mode have better operation characteristics in power supply reliability, personal security, security of equipment and interference of communication. The application of the arc suppressing coil grounding mode is also researched in this paper.Finally, the paper summarizes this topic research. As a result of the domination of the arc suppressing coil grounding mode, it should be more popularized and applied in the distribution network in the future.The way of thinking, project and conclusions in this thesis have effect on the research to choose the neutral grounding mode not only in I0kV distribution network but also in other power system..The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, all costumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable. To improve the reliability of the power supply network, we must increase the investment cost of the network con- struction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic, between the investment and the loss by calculating the investment on power net and the loss brought from power-off. The thesis analyses on the economic and the reliable of the various line modes, according to the characteristics various line modes existed in the electric distribution net in foshan..First, the thesis introduces as the different line modes in the l0kV electric distribution net and in some foreign countries. Making it clear tow to conduct analyzing on the line mode of the electric distribution net, and telling us how important and necessary that analyses are.Second, it turns to the necessity of calculating the number of optimization subsection, elaborating how it influences on the economy and reliability. Then by building up the calculation mode of the number of optimization subsection it introduces different power supply projects on the different line modes in brief. Third, it carries on the calculation andanalyses towards the reliability and economy of the different line modes of electric distribution net, describing drafts according by the calculation. Then it makes analysis and discussion on the number of optimization subsection.At last, the article make conclusion on the economy and reliability of different line modes, as well as, its application situation. Accordion to the actual circumstance, the thesis puts forward the beneficial suggestion on the programming and construction of the l0kV electric distribution net in all areas in foshan. Providing the basic theories and beneficial guideline for the programming design of the lOkV electric distribution net and building up a solid net, reasonable layout, qualified safe and efficiently-worked electric distribution net.References[1] Wencheng Su. Factories power supply [M]. Machinery Industry Publishing House. 1999.9[2] Jiecai Liu. Factories power supply design guidance [M]. Machinery Industry Publishing House.1999.12[3] Power supply and distribution system design specifications[S].China plans Press. 1996[4] Low-voltage distribution design specifications [S].China plans Press. 1996.6供配电系统摘要电力系统的基本功能是向用户输送电能。
电气系统的保护(外文文献翻译)
Protection of Electrical SystemAll electrical systems have the common purpose of providing electrical energy to the utilization equipment as safely and reliably as is economically feasible .The utilization equipment then converts the electrical energy to other forms, such as mechanical, light, and heat energy .The design of the electrical energy to transmit the electrical energy to the utilization equipment must focus on two basic requirements. First, the system must be adequate to deliver to each piece of equipment the necessary energy on a continuous basis under normal conditions. Second, the system must be designed to minimize power outages and damage in the event that abnormal conditions occur on the system. The following is a list of abnormal conditions that can occur on a system and for which corrective action should be taken:1.Overloads2.Short circuits3.Under voltage4.Single phasing of three phase systems5.Over-voltages and transient surges6.Incorrect synchronizing of frequencies7.Incorrect phase sequence8.Reverse power flowNext in order of priorities is the desirability of keeping damage to the electrical equipment to the absolute minimum so that normal operation can resume as quickly as possible .Finally it makes economic sense, especially with large system can continue to operate normally .This requirement for the least amount of shutdown of the system involves coordination of the protective devices.The protective device has two major functions:(1) to detect an abnormal condition on that portion of the system that it is protecting and (2) to automatically and safely disconnect the faulted portion from the balance of the system .Protective devices such as fuses and most low-voltage circuit breakers combine both the detection unit and the disconnecting means in the one unit. Other types of protectivedevices separate the two functions. For example, medium-and high-voltage circuit breakers normally only perform the disconnecting function. They must be used in conjunction with separate protective relays that detect the abnormal conditions and then initiate the tripping of the circuit breaker. It must be emphasized again that protective devices cannot prevent faults from occurring on the system, but can only minimize their effects.Protective devices are rated for the following:1.Maximum continuous voltage: This is the maximum voltage that can be continuously applied to the device without eventually causing the insulation to fail.2.Maximum continuous current: This is the maximum load current that the device can carry continuously without the contacts or other current-carrying parts overheating.3.Interrupting rating: This is the maximum current that the device can safely interrupt at the specified voltage.4.Short-time current ratings:(a)Momentary: This is the maximum rms current that the device can withstand with regard to mechanical stressing. The maximum stressing occur one half-cycle after the fault starts. This rating is necessary to ensure that the device is not physically damaged before it can operate to disconnect the faulted part of the system.(b) Specified time: This is the maximum rms current that the device can withstand for a specified time 0.5% with regard to thermal stressing .In the case of breakers, it is sometimes necessary under severe short circuits to delay their opening for a very short period of time in order to coordinate with other devices .This rating is necessary to ensure that the breaker is not damaged by heat before it can operate to disconnect the faulted part of the system.Protective RelayingProtective relaying is that area of power system design concerned with minimizing service interruption and limiting damage to equipment when failures occur. The function of protective relaying is to cause the prompt removal of adefective element from a power system .The defective element may have a short circuit or it may be operating in an abnormal manner. Protective relaying systems are designed to detect such failures or abnormal conditions quickly (commensurate with system requirements) and to open a minimum of circuit breakers to isolate the defective element. The effect of quick isolate is threefold: (1) it minimizes or prevents damage to the defective element, thus reducing the time and expense of repairs and permitting quicker restoration of the element to service; (2) it minimizes the power system; and (3) it. maximizes the power that can be transferred on power system. The second and third points are of particular significance because they indicate the important role protective relaying plays in assuring maximum service reliability and in system design. The power that can be transmitted across system without the loss of synchronism is the function of fault clearing times. It is apparent that fast fault clearing times permit a higher power transfer than longer clearing times. High-speed clearing of faults can often provide a means for achieving higher power transfers and thereby defer investment in additional transmission facilities.A protective relaying system is based on detecting fault conditions by continuously monitoring the power system variable such as current, voltage, power, frequency, and impedance. Measuring of currents and voltage is performed by instrument transformers of the potential type (PT) or current type (CT). Instrument transformers feed the measured variables to the relay system, which in return, upon detecting a fault, commands circuit breaker (CB) to disconnect the faulted section of the system.An electric relaying system is divided into several protective zones for generators, transformers, buses, transmission and distribution circuits, and motors. The division is such that zones are given adequate protection while keeping service interruption to a minimum. It is to be noted that each zone is overlapped to avoid unprotected (blind) areas. The connections of current transformers achieve the overlapping. The general philosophy of relay application is divide the power system into zones that can be adequately protected by suitable protective equipment and can be disconnected from the power system in a minimum amount of time and with theleast effect on the remainder of the power system. The protective relaying provided for each zone is divided into two categories: (1) primary relaying and (2) backup relaying. Primary relaying is the first line of defense when failures occur, and is connected to trip only the protective relays will operate to trip all of the breakers within that zone. If a breaker is omitted between two adjacent elements, both elements will be disconnected for a failure in either one. This latter arrangement is illustrated by the unit generator-transformer connection in the power plant. On bulk power generating and transmission systems, primary protection is designed to operate at high speed for all faults. Slower protection may be used in less important system areas but, in general, any system area will benefit by the fastest possible primary relaying.If the fault is not cleared by the primary protection, backup relaying operates to clear the fault from the system. In general, backup relaying disconnects a greater portion of the system to isolate the fault. Backup protection is provided for possible failure in the primary both relay backup as well as breaker backup. Ideally, the backup protection should be arranged so that anything that may cause the primary protection to fail will not also cause failure of the backup protection .Moreover, the backup protection must not operate until the primary protection has been given an opportunity to function. As a result, there is time delay associated with any backup operation. When a short circuit occurs, both the primary and the backup protection start to operate. If the primary protection clears the fault, the backup protection will reset without completing its function. If the fault is not cleared by the primary protection, the backup relaying will time out and trip the necessary breakers to clear the fault from the system.There are two forms of backup protection in common use on power system. They are remote backup and local backup.(1)Remote backup. In remote backup relaying, faults are cleared from thesystem one station away from where the failure has occurred.(2)Local backup. In local backup relaying, faults are cleared locally in thesame station where the failure has occurred. For faults on the protectedline, both the primary and the backup relays will operate to preparetripping the line breaker. Relay backup may be just as fast as the front linerelays. When either of these relays operates to initiate tripping of the linebreaker, it also energizes a timer to start the breaker backup function. Ifthe breaker fails to cleat the fault, the line relays will remain picked up,permitting the timer to time out and trip the necessary other breaker onthe associated bus section.Microcomputer-based RelayingA new development in the field of power system protection is the use of computers (usually microcomputers) for relaying. Although computers provide the same protection as that supplied by conventional relays, there are some advantages to the use of computer-based relaying is much greater than for electromechanical devices. Computer-based relaying samples the values of the current, voltage, and other items covered in the protection scheme several times a second, and by use of A/D converters, change these analog values to digital form and then send them to the computer. In the event of a fault, the computer can calculate the fault’s current values and characteristics, and settings can be changed merely by reprogramming. Computer-based relaying are also capable of locating faults, checking features can be built in and sequence of events information can be downloaded to remote computers for fast analysis of relaying operations.Computer-based relaying system consists of subsystems with well defined functions. Although a specific subsystem may be different in some of its details, these subsystems are most likely to be incorporated in its design in some form. The processor is the center of its organization. It is responsible for the execution of relaying programs, maintenance of various timing functions, and communicating with its peripheral equipment. The Random Access Memory (ROM) or Programmable Read Only Memory (PROM) is used to store the programs permanently. In some cases the programs may execute directly from the ROM if its read time is short enough. If this is not the case, the programs must be copied from the ROM into the PAM during an initialization stage, and then the real-time execution would take placefrom the RAM. The Erasable PROM (EPROM) is needed for storing certain parameters (such as the relaying settings) which may be changed from time to time, but once it is set it must remain fixed even if the power supply to the computer is interrupted.The relaying inputs are currents and voltages -- or, to a lesser extent –digital signals indicating contact status. The analog signals must be converted to voltage signals suitable for conversion to digital form. The current and voltage signals obtained from current and volts. The current inputs must be converted to voltages by resistive shunts. As the normal current transformer secondary currents may be as high as hundreds of amperes, shunts of Digital Converter (ADC). An alternative arrangement would be to use an auxiliary current another function; that of providing electrical isolation between the main CT secondary and the computer input system. Since the digital computer can be programmed to perform several functions as long as it has the input and output signals needed for those functions. It is a simple matter to the relaying computer to do many other substation task, for example , measuring and monitoring flows and voltages in transformers and transmission lines, controlling the opening and closing of circuit breakers and switches, providing backup for other devices that have failed, are all functions that can be taken over by the relaying computer. With the program ability and communication capability, the computer-based relaying computer offers yet another possible advantage that is not easily realizable in a conventional system. This is the ability to change the relay characteristics (settings) as the system conditions warrant it. With reasonable prospects of having affordable computer-based relaying which can be dedicated to a single protection function, attention soon turned to the opportunities offered by computer-based relaying to integrate them into a substation, perhaps even a system-wide network. Integrated computer systems for substations which handle relaying, monitoring, and control tasks offer novel opportunities for improving overall system performance.。
(完整版)电气专业英文文献
An Expert System for Transformer Fault Diagnosis Using Dissolved Gas Analysis1. INTRODUCTIONThe power transformer is a major apparatus in a power system, and its correct functioning its vital to minimize system outages, many devices have evolved to monitor the serviceability of power transformers. These devices, such as, Buchholz relays or differential relays, respond only to a severe power failure requiring immediate removal of the transformer from service, in which case, outages are inevitable. Thus, preventive techniques for early detection faults to avoid outages would be valuable. In this way, analysis of the mixture of the faulty gases dissolved in insulation oil of power transformer has received worldwide recognition as an effective method for the detection of oncipient faults. Many researchers and electrical utilities have reported on their experience and developed interpretative criteria on the basis of DGA. However, criteria tend to vary from utility to utility. Therefore, transformer diagnosis is still in the heuristic stage. For this reason, knowledge-based programming is a suitable approach to implement in such a diagnostic problem.Based on the interpretation of DGA, a prototype of an expert system for diagnosis of suspected transformer faults and their maintenance procedures is proposed. The significant source in this knowledge base is the gas ratio method. Some limitations of this approach are overcome by incorporating the diagnostic procedure and the synthetic expertise method. Furthermore, data bases adopted from TPC'S gas records of transformers are incorporated into the expert system to increase the practical performance. Uncertainty of diagnosis is managed by using fuzzy set concepts. This expert system is constructed with rule based knowledge representation, since it can be expressed by experts. The expert system building tool,knowledge Engineering System(KES), is used in the development of the knowledge system because, it has excellent man-machine interface that provides suggestions. Moreover,its inference strategy is similar to the MYCIN. A famous rule-based expert system used for medical diagnosis. The uncertainty of human qualitative diagnostic expertise, e.g., key gasanalysis, and another quantitative imprecision, such as, norms threshold and gas ratio boundaries etc., are smoothed by appropriate fuzzy models. With the results of such implementation, different certainty factors will be assigned to the corresponding expertise variables. Both event-driven(forward chaining) and goal-driven (backward chaining) inferences are used in the inference engine to improve the inference efficiency. To demonstrate the feasibility of the proposed expert system, around hundreds of TPC historical gas records have been tested. It is found that more appropriate faulty types and maintenance suggestions can support the maintenance personals to increase the performance of transformer diagnosis.2. DEVELOPMENT OF DIAGNOSIS AND INTERPRETATIONLike many diagnostic problems, diagnosis of oil-immersed power transformer is a skilled task. A transformer may function well externally with monitors, while some incipient deterioration may occur internally to cause a fatal problem in the latter development. According to a Japanese experience, nearly 80% of all faults result from incipient deteriorations. Therefore, faults should be identified and avoided at the earliest possible stage by some predictive maintenance technique. DGA is one of the most popular techniques for this problem. Fault gases in transformers are generally produced by oil degradation and other insulating material, e.g., cellulose and paper. Theoretically, if an incipient or active fault is present, the individual dissolved gas concentration, gassing rate, total combustible gas(TCG) and cellulose degradation are all significantly increased. By using gas chromatography to analyse the gas dissolved in a transformer's insulating oil, it becomes feasible to judge the incipient fault types. This study is concerned with the following representative combustible gases; hydrogen(H2), methane(C2H2), ethane(C2H6), ethylene(C2H2) and carbon monoxide(C0).Many interpretative methods based on DGA to the nature of incipient deterioration have been reported. Even under normal transformer operational conditions, some of these gases may be formed inside. Thus, it is necessary to build concentration norms from a sufficiently large sampling to assess the statistics. TPC investigated gas data from power transformers to construct its criteria. The developedknowledge base in this paper is partially based on these data. On the hand, Dornerburg developed a method to judge different faults by rating pairs of concentrations of gases, e.g., CH/H, GH/C3H4, with approximately equal solubility and fusion coefficients. Rogers established mare comprehensive ratio codes to interpret the thermal fault types with theoretical thermodynamic assessments. This gas ratio method was promising because it eliminated the effect of oil volume and simplified the choice of units. Moreover, it systematically classified the diagnosis expertise in a table form. Table 1 displays the ratio method as proposed by Rogers. The dissolved gas may vary with the nature and severity of different faults. By analyzing the energy density of faults, it's possible to distinguish three basic fault processes:overheating(pyrolysis), corona(partial dischatge) and arcing discharge. Corona and arcing arise from electrical faults, while overheating is a thermal fault. Both types of faults my lead to deterioration, while damage from overheating is typically less than that from electrical stress. Infect, different gas trends lead to different faulty types, the key gas method is identified. For example, large amounts of CH and H are produced with minor arcing fault 4 quantities of CH 2aid C2H2 may bea symptom of an arcing fault.3.THE PROPOSED DIAGNOSTIC EXPERT SYSTEMThis study is aimed at developing a rule-based expert system to perform transformer diagnosis similar to a human expert. The details of system processing are described below.3.1 The Proposed Diagnostic MethodDiagnosis is a task that requires experience. It is unwise to determine an approach from only a few investigations. Therefore, this study uses the synthetic expertise method with the experienced procedure to assist the popular gas ratio method and complete practical performance.3.1.1 Experienced Diagnostic ProcedureThe overall procedure of routine maintenance for transformers is listed. The core of this procedure is based on the implementation of the DGA technique. The gas ratio method is the significant knowledge source. Some operational limitations of the gasratio method exist. The ratio table is unable to cover all possible cases. Minimum levels of gases must be present. The solid insulation involving CO and CO are handled separately and the gas ratio codes have been developed mainly from a free-breathing transformer. Other diagnostic expertise should be used to assist this method. Norms, synthetic expertise method and data base records have been incorporated to complete these limitations. The first step of this diagnostic procedure begins by asking DGA for an oil sample to be tested. More important relevant information about the transformer's condition, such as the voltage level, the preservative type, the on-line-tap-changer(OLTC) state, the operating period and degassed time must be known for further inference. Norms(criteria) Set up by TPC power transformers' gas characteristic data are then used to judge the transformers' condition. For the abnormal cases, the gas ratio method is used to diagnose transformer fault type. If different or unknown diagnosis results are found from these ratio methods, a further synthetic expertise method is adopted. After these procedures, different severity degrees are assigned to allow appropriate corresponding maintenance suggestions.3.1.2 Synthetic Expertise MethodThe ratio trend, norms threshold, key gas analysis and some expertise are considered as different evidences to confirm some special fault types. In other words, more significant evidences have been collected for some special fault type, better assessment of the transformer status is obtained.The ratio trend can be seen as a modification of the conventional gas ratio and key gas method.Obviously, the above gas trends should be incorporated with other evidences under the experienced procedure for practical use. Norms threshold, the gassing rate, the quantity of total combustible gas(TCG), the TPC maintenance expertise and the fuzzy set assignment are all important evidences considered in the synthetic diagnosis.Other expertise based on a transformer historical data base is also used to analyse the characteristics of a case transformer. Section 3.4 gives some details of these rules.3.2 Expert System StructureThe proposed diagnostic expert system is composed of components, working memory, a knowledge base, an inference engine and a man-machine interface. Working memory (global data base) contains the current data relevant to solve the present problem. In this study, most of the diagnostic variables stored in the data base are current gas concentration, some are from the user, others are retrieved from the transformer's historical data base. Note that the fuzzy set concept is incorporated to create fuzzy variables on the request of system reasoning. A knowledge relationship, which uses these facts, as the basis for decision making. The production rule used in this system is expressed in IF-THEN forms. A successful expert system depends on a high quality knowledge base. For this transformer diagnostic system, the knowledge base incorporates some popular interpretative methods of DGA, synthetic expertise method and heuristic maintenance rules. Section 3.4 will describe this knowledge base. Another special consideration in the expert system is its inference engine. The inference engine controls the strategies of reasoning and searching for appropriate knowledge. The reasoning strategy employs both forward chaining(data-driven) and backward chaining(goal-driven). Fuzzy rules, norms rules, gas ratio rules, synthetic expertise rules and some of the maintenance rules and some maintenance rules, use forward chaining.As for the searching strategy in KES, the depth first searching and short-circuit evaluation are adopted. The former can improve the search efficiency by properly arranging the location of significant rules in the inference procedures. The latter strategy only searches the key conditional statements in the antecedent that are responsible for establishing whether the entire rule is true or false. Taking the advantages of these two approaches in the building and structuring of a knowledge base improves inference efficiency significantly.As for man-machine interface. KES has an effective interface which is better than typical knowledge programming languages, such as, PROLOG or LISP. With the help of this interface, the capability of tracing, explaining and training in an expert system is greatly simplified.4.IMPLEMENTATION OF THE PROPOSED EXPERT SYSTEMAn expert system is developed based on the proposed interpretative rules and diagnostic procedures of the overall system. To demonstrate the feasibility of this expert system in diagnosis, the gas data supported by MTL of TPC have been tested. In Taiwan, the MTL of TPC performs the DGA and sends the results to all acting divisions relating to power transformers. In return, these acting divisions are requested to collect and supply their transformer oil samples periodically.After analysing oil samples, more than ten years' worthy gas records are collected and classified into three voltage level, 69KV, 16KV and 345KV. Thus, gas records for one transformer are composed of several groups of data. In the process of DGA interpretation, all of these data may be considered, but only the recent data which have significant effects on diagnosis are listed in the later demonstration. In MTL, all gas concentrations are expressed by pm in volume concentration. 100 pm is equal to 0.01 ml(gas)/100ml(oil).From the expertise of diagnosis, the normal state can be confirmed only by inspection of the transformer's norms level. In practice, most of the transformer oil samples are normal, and this can be inferred successfully on the early execution of this expert system. However, the Success of an expert system is mainly dependent on the capability of diagnosis for the transformers in question. In the implementation, many gas records which are in abnormal condition are chosen to test the Justification of this diagnostic system. A total of 101 transformer records have been executed and the results are summarized in Table 5. Among those implemented, three are listed and demonstrated.Shown in Table 5 are the results of 101 units of transformers in three types of remedy: normal, thermal fault and arc fault. After comparing them with the actual state and expert judgement, a summary of results was obtained. As previously stated, one unit of transformer may include many groups of gas data. In evaluation, we depicted some key groups in one unit to justify because some transformers may have different incipient faults during different operational stages. Some mistakes implemented from testing are caused by the remaining oil in the oil sampling container, unstable gas characteristics of the new degassing sample and some obscuregas types. If more information or new techniques support other uncertain membership functions, they can be added into the knowledge has to enlarge the the performance of this prototype expert system. Furthermore, the parameters described in table 2,3 and 4 are suitable for TPC power transformer. Different regions may be modified the maintenance personnel find more suitable system parameters.5.CONCLUSIONSA prototype expert system is developed on a personal computer using KES. It can diagnose the incipient faults of the suspected transformers and suggest proper maintenance actions. Fuzzy set concept is used to handle uncertain norms thresholds, gas ratio boundaries and key gas analysis. The synthetic method and diagnostic procedure are proposed to assist the situation which can not be handled properly by the gas ratio methods. Results from the implementation of the expert system shows that the expert system is a useful tool to assist human expert and maintenance engineers.The knowledge base of this expert system is incorporated within the popular interpretative method of DGA, synthetic expertise and heuristic maintenance rules. The data base supported by TPC MTL for about 10 year collection of transformer inspection data is also used to improve the interpretation of diagnosis. Through the development of the proposed expert system, the expertise of TPC MTL can be reserved. In addition, this work can be continued to expand the knowledge base by adding any new experience, measurement and analysis techniques.。
推荐-供配电类英文原文 精品
附录二：英文原文Electric power distributionAn electric power distribution system is the final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2kV and 35kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises. Distribution transformers again lower the voltage to the utilization voltage of household appliances and typically feed several customers through secondary distribution lines at this voltage. mercial and residential customers are connected to the secondary distribution lines through service drops. Customers demanding a much larger amount of power may be connected directly to the primary distribution level or the sub transmission level.HistoryFurther information: History of electric power transmissionElectric power distribution only became necessary in the 1880s when electricity started being generated at power stations. Before that electricity was usually generated where it was used. The first power distribution systems installed in European and US cites were used to supply lighting: arc lighting running on very high voltage (usually higher than 3000 volt) alternating current (AC) or direct current (DC), and incandescent lighting running on low voltage (100 volt) direct current. Both were supplanting gas lighting systems, with arc lighting taking over large area/street lighting, and incandescent lighting replacing gas for business and residential lighting.Due to the high voltages used in arc lighting, a single generating station could supply a long string of lights, up to 7-mile (11 km) long circuits, since the capacity of a wire is proportional to the square of the current traveling on it, each doubling of the voltage would allow the same size cable to transmit the same amount of power four times the distance. Direct current indoor incandescent lighting systems (for example the firstEdison Pearl Street Station installed in 1882), had difficulty supplying customers more than a mile away due to the low 110 volt system being used throughout the system, from the generators to the final use. The Edison DC system needed thick copper conductor cables, and the generating plants needed to be within about 1.5 miles (2.4 km) of the farthest customer to avoid excessively large and expensive conductors. Introduction of the AC transformerTrying to deliver electricity long distance at high voltage and then reducing it to a fractional voltage for indoor lighting became a recognized engineering roadblock to electric power distribution with many, not very satisfactory, solutions tested by lighting panies. The mid-1880s saw a breakthrough with the development of functional AC transformers that allowed the voltage to be "stepped up" to much higher transmission voltages and then dropped down to a lower end user voltage. With much cheaper transmission costs and the greater economies of scale of having large generating plants supply whole cities and regions, the use of AC spread rapidly.In the US the petition between direct current and alternating current took a personal turn in the late 1880s in the form of a "War of Currents" when Thomas Edison started attacking George Westinghouse and his development of the first US AC transformer systems, pointing out all the deaths caused by high voltage AC systems over the years and claiming any AC system was inherently dangerous. Edison's propaganda campaign was short lived with his pany switching over to AC in 1892.AC became the dominant form of transmission of power with innovations in Europe and the US in electric motor designs and the development of engineered universal systems allowing the large number of legacy systems to be connected to large AC grids.In the first half of the 20th century, the electric power industry was vertically integrated, meaning they one pany did generation, transmission, distribution, and metering and billing. Starting in the 1970s and 1980s nations began the process of deregulation and privatisation, leading to electricity markets. The distribution system would remain regulated, but generation, retail, and sometimes transmission systems were transformed into petitive marketsGeneration and transmissionElectric power begins at a generating station, where the potential difference can be as high as 13,800 volts. AC is usually used. Users of large amounts of DC power such as some railway electrification systems, telephone exchanges and industrial processes such as aluminium smelting usually either operate their own or have adjacent dedicated generating equipment, or use rectifiers to derive DC from the public AC supply. However, High-voltage DC can be advantageous for isolating alternating-current systems or controlling the quantity of electricity transmitted. For example, Hydro-Quebec has a direct-current line which goes from the James Bay region to Boston.From the generating station it goes to the generating station’s switch yard where a step-up transformer increases the voltage to a level suitable for transmission, from 44,000 to 765,000 volts. Once in the transmission system, electricity from each generating station is bined with electricity produced elsewhere. Electricity is consumed as soon as it is produced. It is transmitted at a very high speed, close to the speed of light.Distribution overviewThe transition from transmission to distribution happens in a power substation, which has the following functions:•Circuit breakers and switches enable the substation to be disconnected from the transmission grid or for distribution lines to be disconnected.•Transformers step down transmission voltages, 35kV or more, down to primary distribution voltages. These are medium voltage circuits, usually 600-35,000 V.•From the transformer, power goes to the busbar that can split the distribution power off in multiple directions. The bus distributes power to distribution lines, which fan out to customers.Urban distribution is mainly underground, sometimes in mon utility ducts. Rural distribution is mostly above ground with utility poles, and suburban distribution is a mix. Closer to the customer, a distribution transformer steps the primary distribution power down to a low-voltage secondary circuit, usually 120 or 240V, depending on theregion. The power es to the customer via a service drop and an electricity meter. The final circuit in an urban system may be less than 50 feet, but may be over 300 feet for a rural customer.Primary distributionPrimary distribution voltages are 22kV or 11kV. Only large consumers are fed directly from distribution voltages; most utility customers are connected to a transformer, which reduces the distribution voltage to the low voltage used by lighting and interior wiring systems.V oltage varies according to its role in the supply and distribution system. According to international standards, there are initially two voltage groups: low voltage (LV): up to and including 1,000 V AC (or 1,500 V DC) and high voltage (HV): above 1kV AC (or 1.5kV DC).Network configurationsDistribution networks are divided into two types, radial or network. A radial system is arranged like a tree where each customer has one source of supply. A network system has multiple sources of supply operating in parallel. Spot networks are used for concentrated loads. Radial systems are monly used in rural or suburban areas.Radial systems usually include emergency connections where the system can be reconfigured in case of problems, such as a fault or required replacement. This can be done by opening and closing switches. It may be acceptable to close a loop for a short time.Long feeders experience voltage drop (power factor distortion) requiring capacitors to be installed.Reconfiguration, by exchanging the functional links between the elements of the system, represents one of the most important measures which can improve the operational performance of a distribution system. The problem of optimization through the reconfiguration of a power distribution system, in terms of its definition, is a historical single objective problem with constraints. Since 1975, when Merlin and Back introduced the idea of distribution system reconfiguration for active power loss reduction, until nowadays, a lot of researchers have proposed diverse methods andalgorithms to solve the reconfiguration problem as a single objective problem. Some authors have proposed Pareto optimality based approaches (including active power losses and reliability indices as objectives). For this purpose, different artificial intelligence based methods have been used: microgenetic, branch exchange, particle swarm optimization and non-dominated sorting genetic algorithm.Rural servicesRural electrification systems tend to use higher distribution voltages because of the longer distances covered by distribution lines (see Rural Electrification Administration). 7.2, 12.47, 25, and 34.5kV distribution is mon in the United States; 11kV and 33kV are mon in the UK, Australia and New Zealand; 11kV and 22 kV are mon in South Africa. Other voltages are occasionally used. Distribution in rural areas may be only single-phase if it is not economical to install three-phase power for relatively few and small customers.Rural services normally try to minimize the number of poles and wires. Single-wire earth return (SWER) is the least expensive, with one wire. It uses higher voltages (than urban distribution), which in turn permits use of galvanized steel wire. The strong steel wire allows for less expensive wide pole spacing. In rural areas a pole-mount transformer may serve only one customer.Higher voltage split-phase or three phase service, at a higher infrastructure and a higher cost, provide increased equipment efficiency and lower energy cost for large agricultural facilities, petroleum pumping facilities, or water plants.In New Zealand, Australia, Saskatchewan, Canada, and South Africa, single wire earth return systems (SWER) are used to electrify remote rural areas.Secondary distributionElectricity is delivered at a frequency of either 50 or 60 Hz, depending on the region. It is delivered to domestic customers as single-phase electric power. Seen in an oscilloscope, the domestic power supply in North America would look like a sine wave, oscillating between -170 volts and 170 volts, giving an effective voltage of 120 volts. Three-phase power is more efficient in terms of power delivered per cable used, and ismore suited to running large electric motors. Some large European appliances may be powered by three-phase power, such as electric stoves and clothes dryers.A ground connection is normally provided for the customer's system as well as for the equipment owned by the utility. The purpose of connecting the customer's system to ground is to limit the voltage that may develop if high voltage conductors fall down onto lower-voltage conductors which are usually mounted lower to the ground, or if a failure occurs within a distribution transformer. Earthing systems can be TT, TN-S, TN-C-S or TN-C.Regional variations220-240 volt systemsMost of the world uses 50 Hz single-phase 220 or 230 V residential and light industrial service. In this system, the primary distribution network supplies a few substations per area, and the 230 V power from each substation is directly distributed. A live (hot) wire and neutral are connected to the building from one phase of three phase service. Single-phase distribution is used where motor loads are light. In Europe, electricity is normally distributed for industry and domestic use by the three-phase, four wire system. This gives a three-phase voltage of 400 volts wye service and a single-phase voltage of 230 volts. For industrial customers, 3-phase 690 / 400 volt is also available. Large industrial customers have their own transformers with an input from 10kV to 220kV. In the UK a typical urban or suburban low-voltage substation would normally be rated between 315kV A and 1MV A and supply a whole neighborhood.110-120 volt systemsMost of the Americas use 60 Hz AC, the 120/240 volt split phase system domestically and three phase for larger installations. pared to European systems, North American ones have more step-down transformers near customers. This is because the higher domestic voltage used in Europe (230 V vs 120 V) may be carried over a greater distance with acceptable power loss.In the electricity sector in Japan, the standard frequencies for AC are 50 and 60 Hz. In Japan parts of the country use 50 Hz, while other parts use 60 Hz. This is a relic of the 1800s. Some local providers in Tokyo imported 50 Hz German equipment, while thelocal power providers in Osaka brought in 60 Hz generators from the United States. The grids grew until eventually the entire country was wired. Today the frequency is 50 Hz in Eastern Japan (including Tokyo, Yokohama, Tohoku, and Hokkaido) and 60 Hertz in Western Japan (including Nagoya, Osaka, Kyoto, Hiroshima, Shikoku, and Kyushu).Most household appliances are made to work on either frequency. The problem of inpatibility came into the public eye when the 20XX Tōhoku earthquake and tsunami knocked out about a third of the east’s capacity, and power in the west couldn’t be fully shared with the east, since the country does not have a mon frequency.There are four converter stations that move power across Japan’s AC frequency border. Shin Shinano is a back-to-back HVDC facility in Japan which forms one of four frequency changer stations that link Japan's western and eastern power grids. The other three are at Higashi-Shimizu, Minami-Fukumitsu and Sakuma Dam. Together they can move up to 1.2 GW of power east or west.原文出处：https:///wiki/Electric_power_distributionThree-phase electric powerThree-phase electric power is a mon method of alternating-current electric power generation, transmission, and distribution.It is a type of polyphase system and is the most mon method used by electrical grids worldwide to transfer power. It is also used to power large motors and other heavy loads. A three-phase system is usually more economical than an equivalent single-phase at the same line to ground voltage because it uses less conductor material to transmit electrical power. The three-phase system was independently invented by Galileo Ferraris, Mikhail Dolivo-Dobrovolsky, Jonas Wenström and Nikola Tesla in the late 1880s.PrincipleIn a symmetric three-phase power supply system, three conductors each carry an alternating current of the same frequency and voltage amplitude relative to a mon reference but with a phase difference of one third the period. The mon reference isusually connected to ground and often to a current-carrying conductor called the neutral. Due to the phase difference, the voltage on any conductor reaches its peak at one third of a cycle after one of the other conductors and one third of a cycle before the remaining conductor. This phase delay gives constant power transfer to a balanced linear load. It also makes it possible to produce a rotating magnetic field in an electric motor and generate other phase arrangements using transformers (For instance, a two phase system using a Scott-T transformer).The symmetric three‐phase systems described here are simply referred to as three‐phase systems because, although it is possible to design and implement asymmetric three‐phase power systems (i.e., with unequal voltages or phase shifts), they are not used in practice because they lack the most important advantages of symmetric systems.In a three‐phase system feeding a balanced and linear load, the sum of the instantaneous currents of the three conductors is zero. In other words, the current in each conductor is equal in magnitude to, but with the opposite sign of, the sum of the currents in the other two. The return path for the current in any phase conductor is the other two phase conductors.pared to a single-phase AC power supply that uses two conductors (phase and neutral), a three-phase supply with no neutral, the same phase-to-ground voltage and current capacity per phase can transmit three times as much power using just 1.5 times as many wires (i.e., three instead of two). Thus, the ratio of capacity to conductor material is doubled. The same (but not the other properties of three-phase power) can also be attained with a center-grounded single-phase system.Three-phase systems may also utilize a fourth wire, particularly in low-voltage distribution. This is the neutral wire. The neutral allows three separate single-phase supplies to be provided at a constant voltage and is monly used for supplying groups of domestic properties which are each single-phase loads. The connections are arranged so that, as far as possible in each group, equal power is drawn from each phase. Further up the distribution system, the currents are usually well balanced. Transformers may be wired in a way that they have a four‐wire secondary but a three‐wire primary whileallowing unbalanced loads and the associated secondary‐side neutral currents.Three-phase supplies have properties that make them very desirable in electric power distribution systems:The phase currents tend to cancel out one another, summing to zero in the case of a linear balanced load. This makes it possible to reduce the size of the neutral conductor because it carries little or no current. With a balanced load, all the phase conductors carry the same current and so can be the same size.Power transfer into a linear balanced load is constant, which helps to reduce generator and motor vibrations.Three-phase systems can produce a rotating magnetic field with a specified direction and constant magnitude, which simplifies the design of electric motors.Most household loads are single-phase.In North American residences, three-phase power might feed a multiple-unit apartment block, but the household loads are connected only as single phase. In lower-density areas, only a single phase might be used for distribution.Some large European appliances may be powered by three-phase power, such as electric stoves and clothes dryers.Wiring for the three phases is typically identified by color codes which vary by country. Connection of the phases in the right order is required to ensure the intended direction of rotation of three-phase motors. For example, pumps and fans may not work in reverse. Maintaining the identity of phases is required if there is any possibility two sources can be connected at the same time; a direct interconnection between two different phases is a short-circuit.原文出处：https:///wiki/Three-phase_electric_power。
电气高层建筑供配电系统设计大学毕业论文英文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：高层建筑供配电系统设计文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14Power supply system of high-rise building designAbstract: With the continuous development of city size, more and more high-rise buildings, therefore, high-rise building electrical design to the designers had to face. In this paper, an engineering example, describes the electrical design of high-rise buildings and some of the more typical issues of universal significance, combined with the actual practice of an engineering solution to the problem described.Key words: high-rise building; electrical design; distribution; load calculation1 Project OverviewThe commercial complex project, with a total construction area of 405570m2, on the ground floor area of 272330m2, underground construction area of 133240m2, the main height of 99m. Project components are: two office buildings, construction area is 70800m2, 28 layers, the standard story is 3.2m.2 Load Calculation1) Load characteristics: electric load, much larger than the "national civil engineering technical measures" Large 120W/m2 indicators, especially in the electricity load more food, and different types of food and beverage catering different cultural backgrounds also high.2) the uncertainty of a large load, because the commercial real estate rents are often based on market demand, and constantly adjust the nature of the shops, making the load in the dynamic changes.3) There is no specification and technical measures in the different types of commercial projects refer to the detailed parameters of the shops, engineering design load calculation in the lack of data, in most cases to rely on staff with previous experience in engineering design calculations.Load the selection of parameters: for the above problems, the load calculation, the first developer of sales and good communication, to determine the form of layers of the forms and nature of floor area, which is calculated on the basis of electrical load basis; followed to determine parameter index within the unit area of shops is also very important and complex because there is no clear indicator of the specification can refer to; and different levels of economic development between cities is not balanced, power indices are also different; will be in the same city, different regions have different consumer groups .3) the need to factor in the choice: parameters determined, the need for load calculation. Need to factor commonly used method, the calculation will not repeat them. Need to explore is the need for coefficient selection, which in the current specifications, manuals and the "unified technical measures" is also not clear requirements, based on years of design experience that most end shops in the distribution or level within the household distribution box with case Kx generally take a while, in the calculation of the loop route to take 0.7 to 0.8, the distribution transformers in the substation calculations take 0.4 to 0.6.3 substations setLoad calculation based on the results of this project the total installed capacity of transformer 43400Kv.A, after repeated consultations with the power company,respectively, in the project in northern, central and southern three sections set the three buildings into three power substations, 1 # set 6 sets 2500Kv.A transformer substation, take the northern section of power supply; 2 # 4 1600Kv.A transformer substations located, plus 6 sets 2000Kv.A transformers, take the middle of the power supply, in addition to 5 Taiwan 10Kv.A high-pressure water chillers (total 4000Kv.A); 3 # substation located 2 units plus 2 units 1000Kv.A 2000Kv.A transformers, take the southern section of A, B two office supply. 10Kv power configuration of this project into two points, each at the two 10Kv lines, the power company under the provisions of 10Kv power capacity: maximum load per channel is about to 11000Kv.A, two is the 22000Kv.A, design # 1 , 3 # combination of a substation 10Kv, power line, with a total capacity of 21000Kv.A; 2 # substation transformers and 10Kv, 10Kv chillers sharing a power line, with a total capacity of 22400Kv.A. The design of the substation layout, in addition to meeting regulatory requirements, it also need to consider the high-pressure cabinets, transformers and low voltage power supply cabinet by order of arrangement, especially in low voltage distribution cabinet to feed the cable smooth and easy inspection duty problems are not seriously consider the construction of the cable crossing will cause more long detour, a waste of floor space, and convenient inspections and other issues.4 small fire load power supplyIn the design of large commercial projects often encounter small fire load of electrical equipment and more dispersed distribution, if fed by a substation, a substation will be fed a lot of low-voltage low-current counter circuit breaking capacity circuit breaker and conductor of the dynamic and thermal stability in a certain extent. According to GB50045-1995 "fire protection design of tall buildings," rule "should be used in Fire Equipment dedicated power supply circuit, the power distribution equipment shall be provided with clear signs." Interpretation of the provisions of the power supply circuit means "from the low-voltage main distribution room (including the distribution of electrical room) to last a distribution box, and the general distribution lines should be strictly separated." In this design, the use of methods to increase the level of distribution, that is different from the substation bus segments, respectively, a fire fed a special circuit, set in place two distribution cabinets, distribution cabinets and then the resulting radial allocated to the end of the dual power to vote each box, so that not only meets the specification requirements for dedicated power supply circuit, but also to avoid feeding the substation level of many small current loop.5, the choice of circuit breaker and conductorCommercial real estate projects use the room as the uncertainty in the choice of circuit breakers and conductors must be considered in a certain margin to meet the needs caused by adjustment of the load changes. According to this characteristic, increased use in the design of the plug bus-powered, not only meet the requirements of large carrying capacity, and also allows the flexibility to increase supply and distribution, are reserved in each shaft in the plug-box backup in order to change, according to changes in upper and lower load, to adjust. For example: a bus is responsible for a shaft 1 to 3 layers of power, when a layer due to the change in capacity increases, while the 3-layer capacity is reduced, you can use a spare plug box layer off the 3-layer 1 layer capacity rationing . This level distribution in the substation, select the circuit breaker to choose the settingvalue when the circuit breaker to adjust to changes at the end to adjust the load setting value; in the bus and the transformer circuit breaker according to the choice of the general framework of values to select . For example: Route certain equipment capacity 530Kv, Kx take 0.7 to calculate current of 704A, select the frame circuit breaker is 1000A, tuning is 800A; current transformer for the 1000/50; bus carrying capacity for the 1000A, this road can meet the maximum 1000A current load requirements, even if there is adjustment, power distribution switches and circuit can not make big changes.6 layer distribution box setAccording to the division of layers of fire protection district, respectively numbered as A ~ K layers within the set level shaft for the retail lighting power distribution box, with one on one power supply shops in radial power. Should be noted that the forms of the complex layers of layers of fire partition, does not correspond to the lower, making some of shaft power in charge of the fire district at the same time, also responsible for the power supply adjacent to the fire district. At design time, using the principle of proximity, while also taking into account the burden of the whole trunk load conditions, so that each shaft as far as possible a more balanced load.7 public area distribution box setTaking into account the future needs of the business re-decoration of public areas must be reserved for power. Here the design needs to consider the following points: ①question of how much reserve power, lighting and electricity, which according to GB50034-2004 "Architectural Lighting Design Standards" table of Article 6.1.3 and 6.1.8, commercial building lighting power density value, high-end supermarkets, business offices as 20W/m2, under the "decorative lighting included 50% of the total lighting power density calculation" requirements, using the reserved standard 40W/m2. ②In order to facilitate the decoration in each partition set fire lighting in public areas and emergency lighting distribution box distribution box, in order to identify the electrical power distribution decoration cut-off point.③the staircase, storage rooms and other parts of the decoration does not need to do, set the power distribution circuit or a separate distribution box, try not to be reserved from the public area of electricity distribution board fed hardcover out.④control of lighting in public areas, the majority in two ways, namely, C-BUS control system or the BA system, the use of C-BUS has the advantage of more flexible control, each road can be fed out of control, adjustable light control; shortcomings is a higher cost. BA system control advantages of using low cost, simple control; disadvantage is that the exchanges and contacts for the three-phase, three-way control may be related both to open, or both, in the decoration of the contacts required to feed the power supply circuit diverge to avoid failure blackouts.Design of distribution box 8In the commercial real estate design, shop design is often only a meter box, and outlet route back to the needs of the user according to their second design, but the shops are difficult to resolve within the power supply fan coil units, air-conditioning system as a whole can not debug. The project approach is to add a circuit breaker in the meter box for the coil power supply, another way for users to use the second design, as shown below.User distribution box design9 distribution cabinet / box number and distribution circuitsLarge-scale projects are often low voltage distribution cabinet / box number, low-voltage circuits to feed the more often there will be cabinet / box number and line number duplication, resulting in the design and the future looks difficult maintenance and overhaul. The project has three 10Kv substations, 20 transformer, hundreds of low-voltage fed out of the closet, fed the circuit more. Accordance with the International Electrotechnical Commission (IEC) and the Chinese national standard requirements: ①All the distribution number to be simple and clear, not too box and line numbers are not repeated.②number to simple and clear, not too long. ③distinction between nature and type of load. ④law was easy to find, make viewer at a glance. Based on the above requirements and on the ground, fire district and the underground construction industry form the different conditions, using two slightly different ways. Essential for the underground garage, uses a single comparison, also relatively fire district neat, according to fire district number, such as AL-BL-1 / 1, AP and APE, the meaning of the letters and numbers: AL on behalf of lighting distribution (AP on behalf of Power distribution box, APE on behalf of the emergency power distribution box); BI on behalf of the basement; 1 / 1 for partition 1, I fire box. Above ground is more complex, more fire district, and on the fire district does not correspond to the lower, according to shaft number is better, such as AL-1-A1, AP, and APE, letters and numbers mean: 1 represents a layer; A1 on behalf of A, No. 1 shaft fed a distribution box. Fed a low-voltage circuits, such as the number of uses: W3-6-AL-1-A1, W3-6) indicates that the route back to power supply transformer 3, 6, feed the power distribution cabinet, AL-1-A1, said the then the first loop of the distribution box for the AL-1-A1 and so on, and so on.10 ConclusionWith more and more complex commercial design projects, designers need to continually improve the design level, designed to make fine. These are only bits of the design in the business lessons learned, and the majority of designers want to communicate高层建筑供配电系统设计摘要：随着城市规模的不断发展，高层建筑越来越多，因此，高层建筑电气设计就成为设计者不得不面对的问题。
电气外文文献及翻译
24.437 电力电子正弦脉宽调制如图1所示，电压源逆变器的开关可以按要求打开和关闭。
用最简单的方法，顶部的开关打开，如果每个周期打开和关闭，则方波的波形结果只有一次。
但是如果改进谐波的数据则在个周期内可以实现多次打开关闭。
图1 简单的电压源逆变器 如图2所示，用最直接的执行方式，所期望的输出电压是通过比较预期的参考波形与高频率的三角载波(调制信号) 生成的，无论直流电压是正还是负，信号电压的输出只根据信号电压是否大于或小于载波波形，要注意的是，在此期间一个三角载波周期的平均电压即信号的振幅加到负载形成正比(假定不变)。
经过一段时间，三角载波的负荷是正比于幅值的信号，在这期间，由此产生的方波包含有在它低频元件所需波形的幅值，也具有较高频率分量在一个载波临近频率的幅值。
需要注意的是，由于PWM 使得总谐波不失真，均方根的平均交流电压波形幅值仍与直流电压相等。
谐波分量只是转移到了更高的平率范围，并由电感式交流系统自动过滤。
当正弦波调制信号的振幅为Am ，三角载波的振幅为Ac 时，它们的调制指数就是m=Am/ Ac 。
因此，控制调制指数控制着输出电压的幅值。
如图3所示，fc/fm=21 ，t=L/R=T/3，T 为基本周期，由于感性元件的存在，高频成分不能明显的传播到交流网络(或负载)，所以具有足够高的载波频率。
然而，由于具有较高的载波频率，从而导致在更多的功率损耗。
所以，在电力系统的应用中，通常认为使用2-15kHz 的开关频率最为合适。
此外，在三相系统中，建议使用)(,3N k k f f mc ∈=，使得三个波形对称。
图2 主要的脉宽调制图3 SPWM的fc/fm=48，L/R=T/3如图4所示，该过程是比较合适的，因为在该图中有三角载波，其中没有交集的载体作为信号周期。
然而，这种“超调”在一定量的范围内往往是允许获得更大的交流电压，使电压频谱呈现出差异。
需要注意的是，使用一个额外的比率形成一个反周期超过360°的对称波形。
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毕业设计（论文）外文文献翻译文献、资料中文题目：供配电系统文献、资料英文题目：POWER SUPPLY AND DISTRIBUTIONSYSTEM文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14POWER SUPPLY AND DISTRIBUTION SYSTEMABSTRACTThe basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, allcostumers expect to pay the lowest price for the highest reliability, but don't consider that it's self-contradictory in the co-existence of economy and reliable.To improve the reliability of the power supply network, we must increase the investment cost of the network construction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic,between the investment and the loss by calculating the investment on power net and the loss brought from power-off.KEYWARDS：power supply and distribution,power distribution reliability，reactive compensation,load distributionTEXTThe revolution of electric power system has brought a new big round construction,which is pushing the greater revolution of electric power technique along with the application of new technique and advanced equipment. Especially, the combination of the information technique and electric power technique, to great ex- tent, has improved reliability on electric quality and electric supply. The technical development decreases the cost on electric construction and drives innovation of electric network. On the basis of national and internatio- nal advanced electric knowledge, the dissertation introduces the research hotspot for present electric power sy- etem as following.Firstly, This dissertation introduces the building condition of distribution automation(DA), and brings forward two typical construction modes on DA construction, integrative mode and fission mode .It emphasize the DA structure under the condition of the fission mode and presents the system configuration, the main station scheme, the feeder scheme, the optimized communication scheme etc., which is for DA research reference.Secondly, as for the (DA) trouble measurement, position, isolation and resume, This dissertation analyzes the changes of pressure and current for line problem, gets math equation by educing phase short circuit and problem position under the condition of single-phase and works out equation and several parameter s U& , s I& and e I& table on problem . It brings out optimized isolation and resume plan, realizes auto isolation and network reconstruction, reduces the power off range and time and improves the reliability of electric power supply through problem self- diagnoses and self-analysis. It also introduces software flow and use for problem judgement and sets a model on network reconstruction and computer flow.Thirdly, electricity system state is estimated to be one of the key techniques in DA realization. The dissertation recommends the resolvent of bad measurement data and structure mistake on the ground of describing state estimate way. It also advances a practical test and judging way on topology mistake in state estimate about bad data test and abnormity in state estimate as well as the problem and effect on bad data from state measure to state estimate .As for real time monitor and control problem, the dissertation introduces a new way to solve them by electricity break and exceptional analysis, and theway has been tested in Weifang DA.Fourthly, about the difficulty for building the model of load forecasting, big parameter scatter limit and something concerned, the dissertation introduces some parameters, eg. weather factor, date type and social environment effect based on analysis of routine load forecasting and means. It presents the way for electricity load forecasting founded on neural network(ANN),which has been tested it’s validity by example and made to be good practical effect.Fifthly, concerning the lack of concordant wave on preve nting concordant wave and non-power compensation and non-continuity on compensation, there is a topology structure of PWM main circuit and nonpower theory on active filter the waves technique and builds flat proof on the ground of Saber Designer and proves to be practical. Meanwhile, it analyzes and designs the way of non-power need of electric network tre- nds and decreasing line loss combined with DA, which have been tested its objective economic benefit throu- gh counting example.Sixthly, not only do the dissertation design a way founded on the magrginal electric price fitted to our present national electric power market with regards to future trends of electric power market in China and fair trade under the government surveillance, that is group competitio n in short-term trade under the way of grouped price and quantity harmony, but also puts forward combination arithmetic, math model of trading plan and safty economical restriction. It can solve the original contradiction between medium and long term contract price and short term competitive price with improvement on competitive percentage and cut down the unfair income difference of electric factory, at the same time, it can optimize the electric limit for all electric factories and reduce the total purchase charge of electric power from burthen curve of whole electric market network.The distribution network is an important link among the power system. Its neutral grounding mode and operation connects security and stability of the power system directly. At the same time, the problem about neutral grounding is associated with national conditions, natural environment, device fabrication and operation. For example, the activity situation of the thunder and lightning, insulating structure and the peripheral interference will influence the choice of neutral grounding mode Conversely, neutral grounding mode affects design, operation, debugs and developing. Generally in the system higher in grade in the voltage, the insulating expenses account for more sizable proportion at the total price of the equipment. It is very remarkable to bring the economic benefits by reducing the insulating level. Usually such system adopt the neutral directly grounding andadopt the autoreclosing to guarantee power supply reliability. On the contrary, the system which is lower in the voltage adopts neutral none grounding to raise power supply reliability. So it is an important subject to make use of new- type earth device to apply to the distribution network under considering the situation in such factors of various fields as power supply reliability, safety factor, over-voltage factor, the choice of relay protection, investment cost, etc.The main work of this paper is to research and choice the neutral grounding mode of the l0kV distribution network. The neutral grounding mode of the l0kV network mainly adopts none grounding, grounding by arc suppressing coil, grounding by reactance grounding and directly grounding. The best grounding mode is confirmed through the technology comparison. It can help the network run in safety and limit the earth electric arc by using auto-tracking compensate device and using the line protection with the detection of the sensitive small ground current. The paper introduces and analyzes the characteristic of all kind of grounding modes about l0kV network at first. With the comparison with technological and economy, the conclusion is drawn that the improved arc suppressing coil grounding mode shows a very big development potential.Then, this paper researches and introduces some operation characteristics of the arc suppressing coil grounding mode of the l0kV distribution network. And then the paper put emphasis on how to extinguish the earth electric arc effectively by utilizing the resonance principle. This paper combines the development of domestic and international technology and innovative achievement, and introduces the computer earth protection and autotracking compensate device. It proves that the improved arc suppressing coil grounding mode have better operation characteristics in power supply reliability, personal security, security of equipment and interference of communication. The application of the arc suppressing coil grounding mode is also researched in this paper.Finally, the paper summarizes this topic research. As a result of the domination of the arc suppressing coil grounding mode, it should be more popularized and applied in the distribution network in the future.The way of thinking, project and conclusions in this thesis have effect on the research to choose the neutral grounding mode not only in I0kV distribution network but also in other power system..The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, all costumers expect to pay the lowest price for the highest reliability, butdon't consider that it's self-contradictory in the co-existence of economy and reliable. To improve the reliability of the power supply network, we must increase the investment cost of the network con- struction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic, between the investment and the loss by calculating the investment on power net and the loss brought from power-off. The thesis analyses on the economic and the reliable of the various line modes, according to the characteristics various line modes existed in the electric distribution net in foshan..First, the thesis introduces as the different line modes in the l0kV electric distribution net and in some foreign countries. Making it clear tow to conduct analyzing on the line mode of the electric distribution net, and telling us how important and necessary that analyses are.Second, it turns to the necessity of calculating the number of optimization subsection, elaborating how it influences on the economy and reliability. Then by building up the calculation mode of the number of optimization subsection it introduces different power supply projects on the different line modes in brief. Third, it carries on the calculation and analyses towards the reliability and economy of the different line modes of electric distribution net, describing drafts according by the calculation. Then it makes analysis and discussion on the number of optimization subsection.At last, the article make conclusion on the economy and reliability of different line modes, as well as, its application situation. Accordion to the actual circumstance, the thesis puts forward the beneficial suggestion on the programming and construction of the l0kV electric distribution net in all areas in foshan. Providing the basic theories and beneficial guideline for the programming design of the lOkV electric distribution net and building up a solid net, reasonable layout, qualified safe and efficiently-worked electric distribution net.。