电气毕业论文英语文献原文+翻译

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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（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.。

电气工程与自动化毕业论文中英文资料外文翻译

电气工程与自动化毕业论文中英文资料外文翻译The Transformer on load ﹠Introduction to DC MachinesIt has been shown that a primary input voltage 1V can be transformed to any desired open-circuit secondary voltage 2E by a suitable choice of turns ratio. 2E is available for circulating a load current impedance. For the moment, a lagging power factor will be considered. The secondary current and the resulting ampere-turns 22N I will change the flux, tending to demagnetize the core, reduce m Φ and with it 1E . Because the primary leakage impedance drop is so low, a small alteration to 1Ewill cause an appreciable increase of primary current from 0I to a new value of 1Iequal to ()()i jX R E V ++111/. The extra primary current and ampere-turns nearly cancel the whole of the secondary ampere-turns. This being so , the mutual flux suffers only a slight modification and requires practically the same net ampere-turns 10N I as on no load. The total primary ampere-turns are increased by an amount 22N I necessary to neutralize the same amount of secondary ampere-turns. In thevector equation , 102211N I N I N I =+; alternatively, 221011N I N I N I -=. At full load,the current 0I is only about 5% of the full-load current and so 1I is nearly equalto 122/N N I . Because in mind that 2121/N N E E =, the input kV A which is approximately 11I E is also approximately equal to the output kV A, 22I E .The physical current has increased, and with in the primary leakage flux towhich it is proportional. The total flux linking the primary ,111Φ=Φ+Φ=Φm p , isshown unchanged because the total back e.m.f.,（dt d N E /111Φ-）is still equal and opposite to 1V . However, there has been a redistribution of flux and the mutual component has fallen due to the increase of 1Φ with 1I . Although the change is small, the secondary demand could not be met without a mutual flux and e.m.f.alteration to permit primary current to change. The net flux s Φlinking thesecondary winding has been further reduced by the establishment of secondaryleakage flux due to 2I , and this opposes m Φ. Although m Φ and 2Φ are indicatedseparately , they combine to one resultant in the core which will be downwards at theinstant shown. Thus the secondary terminal voltage is reduced to dt d N V S /22Φ-=which can be considered in two components, i.e. dt d N dt d N V m //2222Φ-Φ-=orvectorially 2222I jX E V -=. As for the primary, 2Φ is responsible for a substantiallyconstant secondary leakage inductance222222/Λ=ΦN i N . It will be noticed that the primary leakage flux is responsible for part of the change in the secondary terminal voltage due to its effects on the mutual flux. The two leakage fluxes are closely related; 2Φ, for example, by its demagnetizing action on m Φ has caused the changes on the primary side which led to the establishment of primary leakage flux.If a low enough leading power factor is considered, the total secondary flux and the mutual flux are increased causing the secondary terminal voltage to rise with load. p Φ is unchanged in magnitude from the no load condition since, neglecting resistance, it still has to provide a total back e.m.f. equal to 1V . It is virtually the same as 11Φ, though now produced by the combined effect of primary and secondary ampere-turns. The mutual flux must still change with load to give a change of 1E and permit more primary current to flow. 1E has increased this time but due to the vector combination with 1V there is still an increase of primary current.Two more points should be made about the figures. Firstly, a unity turns ratio has been assumed for convenience so that '21E E =. Secondly, the physical picture is drawn for a different instant of time from the vector diagrams which show 0=Φm , if the horizontal axis is taken as usual, to be the zero time reference. There are instants in the cycle when primary leakage flux is zero, when the secondary leakage flux is zero, and when primary and secondary leakage flux is zero, and when primary and secondary leakage fluxes are in the same sense.The equivalent circuit already derived for the transformer with the secondary terminals open, can easily be extended to cover the loaded secondary by the addition of the secondary resistance and leakage reactance.Practically all transformers have a turns ratio different from unity although such an arrangement is sometimes employed for the purposes of electrically isolating one circuit from another operating at the same voltage. To explain the case where 21N N ≠ the reaction of the secondary will be viewed from the primary winding. The reaction is experienced only in terms of the magnetizing force due to the secondary ampere-turns. There is no way of detecting from the primary side whether 2I is large and 2N small or vice versa, it is the product of current and turns which causesthe reaction. Consequently, a secondary winding can be replaced by any number of different equivalent windings and load circuits which will give rise to an identical reaction on the primary .It is clearly convenient to change the secondary winding to an equivalent winding having the same number of turns 1N as the primary.With 2N changes to 1N , since the e.m.f.s are proportional to turns, 2212)/('E N N E = which is the same as 1E .For current, since the reaction ampere turns must be unchanged 1222'''N I N I = must be equal to 22N I .i.e. 2122)/(I N N I =.For impedance , since any secondary voltage V becomes V N N )/(21, and secondary current I becomes I N N )/(12, then any secondary impedance, including load impedance, must becomeI V N N I V /)/('/'221=. Consequently,22212)/('R N N R = and 22212)/('X N N X = . If the primary turns are taken as reference turns, the process is called referring to the primary side.There are a few checks which can be made to see if the procedure outlined is valid.For example, the copper loss in the referred secondary winding must be the same as in the original secondary otherwise the primary would have to supply a differentloss power. ''222R I must be equal to 222R I . ）222122122/()/(N N R N N I •• does infact reduce to 222R I .Similarly the stored magnetic energy in the leakage field)2/1(2LI which is proportional to 22'X I will be found to check as ''22X I . The referred secondary 2212221222)/()/(''I E N N I N N E I E kVA =•==.The argument is sound, though at first it may have seemed suspect. In fact, if the actual secondary winding was removed physically from the core and replaced by the equivalent winding and load circuit designed to give the parameters 1N ,'2R ,'2X and '2I , measurements from the primary terminals would be unable to detect any difference in secondary ampere-turns, kVA demand or copper loss, under normal power frequency operation.There is no point in choosing any basis other than equal turns on primary andreferred secondary, but it is sometimes convenient to refer the primary to the secondary winding. In this case, if all the subscript 1’s are interchanged for the subscript 2’s, the necessary referring constants are easily found; e.g. 2'1R R ≈,21'X X ≈; similarly 1'2R R ≈ and 12'X X ≈.The equivalent circuit for the general case where 21N N ≠ except that m r hasbeen added to allow for iron loss and an ideal lossless transformation has been included before the secondary terminals to return '2V to 2V .All calculations of internal voltage and power losses are made before this ideal transformation is applied. The behaviour of a transformer as detected at both sets of terminals is the same as the behaviour detected at the corresponding terminals of this circuit when the appropriate parameters are inserted. The slightly different representation showing the coils 1N and 2N side by side with a core in between is only used for convenience. On the transformer itself, the coils are , of course , wound round the same core.Very little error is introduced if the magnetising branch is transferred to the primary terminals, but a few anomalies will arise. For example ,the current shown flowing through the primary impedance is no longer the whole of the primary current.The error is quite small since 0I is usually such a small fraction of 1I . Slightlydifferent answers may be obtained to a particular problem depending on whether or not allowance is made for this error. With this simplified circuit, the primary and referred secondary impedances can be added to give:221211)/(Re N N R R += and 221211)/(N N X X Xe +=It should be pointed out that the equivalent circuit as derived here is only valid for normal operation at power frequencies; capacitance effects must be taken into account whenever the rate of change of voltage would give rise to appreciablecapacitance currents, dt CdV I c /=. They are important at high voltages and atfrequencies much beyond 100 cycles/sec. A further point is not the only possible equivalent circuit even for power frequencies .An alternative , treating the transformer as a three-or four-terminal network, gives rise to a representation which is just as accurate and has some advantages for the circuit engineer who treats all devices as circuit elements with certain transfer properties. The circuit on this basiswould have a turns ratio having a phase shift as well as a magnitude change, and the impedances would not be the same as those of the windings. The circuit would not explain the phenomena within the device like the effects of saturation, so for an understanding of internal behaviour .There are two ways of looking at the equivalent circuit:(a) viewed from the primary as a sink but the referred load impedance connected across '2V ,or(b) viewed from the secondary as a source of constant voltage 1V with internal drops due to 1Re and 1Xe . The magnetizing branch is sometimes omitted in this representation and so the circuit reduces to a generator producing a constant voltage 1E (actually equal to 1V ) and having an internal impedance jX R + (actually equal to 11Re jXe +).In either case, the parameters could be referred to the secondary winding and this may save calculation time .The resistances and reactances can be obtained from two simple light load tests. Introduction to DC MachinesDC machines are characterized by their versatility. By means of various combination of shunt, series, and separately excited field windings they can be designed to display a wide variety of volt-ampere or speed-torque characteristics for both dynamic and steadystate operation. Because of the ease with which they can be controlled , systems of DC machines are often used in applications requiring a wide range of motor speeds or precise control of motor output.The essential features of a DC machine are shown schematically. The stator has salient poles and is excited by one or more field coils. The air-gap flux distribution created by the field winding is symmetrical about the centerline of the field poles. This axis is called the field axis or direct axis.As we know , the AC voltage generated in each rotating armature coil is converted to DC in the external armature terminals by means of a rotating commutator and stationary brushes to which the armature leads are connected. The commutator-brush combination forms a mechanical rectifier, resulting in a DCarmature voltage as well as an armature m.m.f. wave which is fixed in space. The brushes are located so that commutation occurs when the coil sides are in the neutral zone , midway between the field poles. The axis of the armature m.m.f. wave then in 90 electrical degrees from the axis of the field poles, i.e., in the quadrature axis. In the schematic representation the brushes are shown in quarature axis because this is the position of the coils to which they are connected. The armature m.m.f. wave then is along the brush axis as shown.. (The geometrical position of the brushes in an actual machine is approximately 90 electrical degrees from their position in the schematic diagram because of the shape of the end connections to the commutator.)The magnetic torque and the speed voltage appearing at the brushes are independent of the spatial waveform of the flux distribution; for convenience we shall continue to assume a sinusoidal flux-density wave in the air gap. The torque can then be found from the magnetic field viewpoint.The torque can be expressed in terms of the interaction of the direct-axis air-gapflux per pole d Φ and the space-fundamental component 1a F of the armature m.m.f.wave . With the brushes in the quadrature axis, the angle between these fields is 90 electrical degrees, and its sine equals unity. For a P pole machine 12)2(2a d F P T ϕπ=In which the minus sign has been dropped because the positive direction of thetorque can be determined from physical reasoning. The space fundamental 1a F ofthe sawtooth armature m.m.f. wave is 8/2π times its peak. Substitution in above equation then givesa d a a d a i K i m PC T ϕϕπ==2 Where a i =current in external armature circuit;a C =total number of conductors in armature winding;m =number of parallel paths through winding;Andm PC K aa π2=Is a constant fixed by the design of the winding.The rectified voltage generated in the armature has already been discussedbefore for an elementary single-coil armature. The effect of distributing the winding in several slots is shown in figure ,in which each of the rectified sine waves is the voltage generated in one of the coils, commutation taking place at the moment when the coil sides are in the neutral zone. The generated voltage as observed from the brushes is the sum of the rectified voltages of all the coils in series between brushesand is shown by the rippling line labeled a e in figure. With a dozen or socommutator segments per pole, the ripple becomes very small and the average generated voltage observed from the brushes equals the sum of the average values ofthe rectified coil voltages. The rectified voltage a e between brushes, known also asthe speed voltage, ism d a m d a a W K W m PC e ϕϕπ==2 Where a K is the design constant. The rectified voltage of a distributed winding has the same average value as that of a concentrated coil. The difference is that the ripple is greatly reduced.From the above equations, with all variable expressed in SI units:m a a Tw i e =This equation simply says that the instantaneous electric power associated with the speed voltage equals the instantaneous mechanical power associated with the magnetic torque , the direction of power flow being determined by whether the machine is acting as a motor or generator.The direct-axis air-gap flux is produced by the combined m.m.f. f f i N ∑ of the field windings, the flux-m.m.f. characteristic being the magnetization curve for the particular iron geometry of the machine. In the magnetization curve, it is assumed that the armature m.m.f. wave is perpendicular to the field axis. It will be necessary to reexamine this assumption later in this chapter, where the effects of saturation are investigated more thoroughly. Because the armature e.m.f. is proportional to flux times speed, it is usually more convenient to express the magnetization curve in termsof the armature e.m.f. 0a e at a constant speed 0m w . The voltage a e for a given fluxat any other speed m w is proportional to the speed,i.e. 00a m m a e w w e =Figure shows the magnetization curve with only one field winding excited. This curve can easily be obtained by test methods, no knowledge of any design details being required.Over a fairly wide range of excitation the reluctance of the iron is negligible compared with that of the air gap. In this region the flux is linearly proportional to the total m.m.f. of the field windings, the constant of proportionality being the direct-axis air-gap permeance.The outstanding advantages of DC machines arise from the wide variety of operating characteristics which can be obtained by selection of the method of excitation of the field windings. The field windings may be separately excited from an external DC source, or they may be self-excited; i.e., the machine may supply its own excitation. The method of excitation profoundly influences not only the steady-state characteristics, but also the dynamic behavior of the machine in control systems.The connection diagram of a separately excited generator is given. The required field current is a very small fraction of the rated armature current. A small amount of power in the field circuit may control a relatively large amount of power in the armature circuit; i.e., the generator is a power amplifier. Separately excited generators are often used in feedback control systems when control of the armature voltage over a wide range is required. The field windings of self-excited generators may be supplied in three different ways. The field may be connected in series with the armature, resulting in a shunt generator, or the field may be in two sections, one of which is connected in series and the other in shunt with the armature, resulting in a compound generator. With self-excited generators residual magnetism must be present in the machine iron to get the self-excitation process started.In the typical steady-state volt-ampere characteristics, constant-speed primemovers being assumed. The relation between the steady-state generated e.m.f. a Eand the terminal voltage t V isa a a t R I E V -=Where a I is the armature current output and a R is the armature circuitresistance. In a generator, a E is large than t V ; and the electromagnetic torque T is acountertorque opposing rotation.The terminal voltage of a separately excited generator decreases slightly with increase in the load current, principally because of the voltage drop in the armature resistance. The field current of a series generator is the same as the load current, so that the air-gap flux and hence the voltage vary widely with load. As a consequence, series generators are not often used. The voltage of shunt generators drops off somewhat with load. Compound generators are normally connected so that the m.m.f. of the series winding aids that of the shunt winding. The advantage is that through the action of the series winding the flux per pole can increase with load, resulting in a voltage output which is nearly constant. Usually, shunt winding contains many turns of comparatively heavy conductor because it must carry the full armature current of the machine. The voltage of both shunt and compound generators can be controlled over reasonable limits by means of rheostats in the shunt field. Any of the methods of excitation used for generators can also be used for motors. In the typical steady-state speed-torque characteristics, it is assumed that the motor terminals are supplied froma constant-voltage source. In a motor the relation between the e.m.f. a E generated inthe armature and the terminal voltage t V isa a a t R I E V +=Where a I is now the armature current input. The generated e.m.f. a E is nowsmaller than the terminal voltage t V , the armature current is in the oppositedirection to that in a motor, and the electromagnetic torque is in the direction to sustain rotation of the armature.In shunt and separately excited motors the field flux is nearly constant. Consequently, increased torque must be accompanied by a very nearly proportional increase in armature current and hence by a small decrease in counter e.m.f. to allow this increased current through the small armature resistance. Since counter e.m.f. is determined by flux and speed, the speed must drop slightly. Like the squirrel-cage induction motor ,the shunt motor is substantially a constant-speed motor having about 5 percent drop in speed from no load to full load. Starting torque and maximum torque are limited by the armature current that can be commutatedsuccessfully.An outstanding advantage of the shunt motor is ease of speed control. With a rheostat in the shunt-field circuit, the field current and flux per pole can be varied at will, and variation of flux causes the inverse variation of speed to maintain counter e.m.f. approximately equal to the impressed terminal voltage. A maximum speed range of about 4 or 5 to 1 can be obtained by this method, the limitation again being commutating conditions. By variation of the impressed armature voltage, very wide speed ranges can be obtained.In the series motor, increase in load is accompanied by increase in the armature current and m.m.f. and the stator field flux (provided the iron is not completely saturated). Because flux increases with load, speed must drop in order to maintain the balance between impressed voltage and counter e.m.f.; moreover, the increase in armature current caused by increased torque is smaller than in the shunt motor because of the increased flux. The series motor is therefore a varying-speed motor with a markedly drooping speed-load characteristic. For applications requiring heavy torque overloads, this characteristic is particularly advantageous because the corresponding power overloads are held to more reasonable values by the associated speed drops. Very favorable starting characteristics also result from the increase in flux with increased armature current.In the compound motor the series field may be connected either cumulatively, so that its.m.m.f.adds to that of the shunt field, or differentially, so that it opposes. The differential connection is very rarely used. A cumulatively compounded motor has speed-load characteristic intermediate between those of a shunt and a series motor, the drop of speed with load depending on the relative number of ampere-turns in the shunt and series fields. It does not have the disadvantage of very high light-load speed associated with a series motor, but it retains to a considerable degree the advantages of series excitation.The application advantages of DC machines lie in the variety of performance characteristics offered by the possibilities of shunt, series, and compound excitation. Some of these characteristics have been touched upon briefly in this article. Stillgreater possibilities exist if additional sets of brushes are added so that other voltages can be obtained from the commutator. Thus the versatility of DC machine systems and their adaptability to control, both manual and automatic, are their outstanding features.中文翻译负载运行的变压器及直流电机导论通过选择合适的匝数比，一次侧输入电压1V 可任意转换成所希望的二次侧开路电压2E 。

电气工程及其自动化专业外文文献英文文献外文翻译方面

1、外文原文（复印件）A: Fundamentals of Single-chip MicrocomputerT h e sin gle -ch ip mi c ro co m p u t e r is t h e cu lm in at io n of b ot h t h e d e ve lo p me nt of t h e d ig ita l co m p u t e r a n d t h e i nte g rated c ircu it a rgu ab l y t h e to w mo st s ign if i cant i nve nt i o n s of t h e 20t h c e nt u ry [1].T h ese to w t yp e s of arch ite ct u re are fo u n d in s in gle -ch ip m i cro co m p u te r. S o m e e mp l oy t h e sp l it p ro gra m /d at a m e m o r y of t h e H a r va rd arch ite ct u re , s h o wn in -5A , ot h e rs fo l lo w t h e p h i lo so p hy, wid e l y ad a p ted fo r ge n e ral -p u rp o se co m p u te rs an d m i cro p ro ce ss o rs , of m a kin g n o l o g i ca l d i st in ct i o n b et we e n p ro gra m an d d ata m e m o r y as in t h e P rin c eto n a rch ite ct u re , sh o wn in -5A.In ge n e ra l te r m s a s in g le -ch ip m ic ro co m p u t e r is ch a ra cte r ized b y t h e in co r p o rat io n of all t h e u n its of a co mp u te r into a s in gle d e vi ce , as s h o w n in F i g3-5A-3.-5A-1A Harvard type-5A. A conventional Princeton computerProgrammemory Datamemory CPU Input& Output unitmemoryCPU Input& Output unitResetInterruptsPowerFig3-5A-3. Principal features of a microcomputerRead only memory (ROM).RO M is u su a l l y fo r t h e p e r m an e nt , n o n -vo lat i le sto rage of an ap p l i cat io n s p ro g ram .M a ny m i c ro co m p u te rs a n d m i cro co nt ro l le rs are inte n d ed fo r h i gh -vo lu m e ap p l i cat io n s a n d h e n ce t h e e co n o m i cal man u fa c t u re of t h e d e vi ces re q u ires t h at t h e co nt e nts of t h e p ro gra m me mo r y b e co mm i ed p e r m a n e nt l y d u r in g t h e m a n u fa ct u re of c h ip s . C lea rl y, t h i s imp l ies a r i go ro u s ap p ro a ch to ROM co d e d e ve lo p m e nt s in ce ch an ges can n o t b e mad e af te r m an u fa ct u re .T h i s d e ve l o p m e nt p ro ces s m ay i nvo l ve e mu l at i o n u sin g a so p h ist icated d e ve lo p m e nt syste m wit h a h ard wa re e mu l at i o n capab i l it y as we ll as t h e u s e of p o we rf u l sof t war e to o l s.So m e m an u fa ct u re rs p ro vi d e ad d it i o n a l ROM o p t io n s b y in clu d in g in t h e i r ran ge d e v ic es w it h (o r inte n d ed fo r u s e wit h ) u se r p ro g ram m a b le m e mo r y. T h e s im p lest of t h e se i s u su a l l y d e v i ce wh i ch can o p e rat e in a m i cro p ro ce s so r mo d e b y u s in g s o m e of t h e in p u t /o u t p u t l in es as an ad d res s a n d d ata b u s fo r a cc es sin g exte rn a l m e m o r y. T h is t yp e o f d e vi ce can b e h ave f u n ct i o n al l y as t h e s in gle ch ip m i cro co m p u t e r f ro m wh i ch it i s d e ri ved a lb e it wit h re st r icted I/O an d a m o d if ied exte rn a l c ircu it. T h e u s e of t h e se RO M le ss d e vi ces i s co mmo n e ve n in p ro d u ct io n circu i ts wh e re t h e vo lu m e d o e s n ot ju st if y t h e d e ve lo p m e nt co sts of cu sto m o n -ch ip ROM [2];t h e re ca n st i ll b e a si gn if i cant sav in g in I/O an d o t h e r ch ip s co m pared to a External Timing components System clock Timer/ Counter Serial I/O Prarallel I/O RAM ROMCPUco nve nt io n al m i c ro p ro ces so r b ased circ u it. M o re exa ct re p l a ce m e nt fo rRO M d e v ice s can b e o b tain ed in t h e fo rm of va ria nts w it h 'p i g g y-b a c k'E P ROM(E rasab le p ro gramm ab le ROM )s o cket s o r d e v ice s w it h E P ROMin stead of ROM 。

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。

电气工程毕业设计外文资料翻译

西华大学毕业设计外文资料翻译附录：外文资料翻译外文资料原文：A Virtual Environment for Protective Relaying Evaluation and TestingA. P. Sakis Meliopoulos and George J. CokkinidesAbstract—Protective relaying is a fundamental discipline of power system engineering. At Georgia Tech, we offer three courses that cover protective relaying: an undergraduate course that devotes one-third of the semester on relaying, a graduate courseentitled “Power System Protection,” and a three-and-a-half-day short course for practicing engineers. To maximize student understanding and training on the concepts,theory, and technology associated with protective relaying, we have developed a number of educational tools, all wrapped in a virtual environment. The virtual environment includes a) a power system simulator, b) a simulator of instrumentation for protective relaying with visualization and animation modules, c) specific protective relay models with visualization and animation modules, and d) interfaces to hardware so that testing of actual relaying equipment can be per formed. We refer to this set of software as the “virtual power system.” The virtual power system permits the in-depth coverage of the protective relaying concepts in minimum time and maximizes student understanding. The tool is not used in a passive way. Indeed, the students actively participate with well-designed projects such as a) design and implementation of multifunctional relays, b) relay testing for specific disturbances, etc. The paper describes the virtual power system organization and “engines,” s uch as solver, visualization, and animation of protective relays, etc. It also discusses the utilization of this tool in the courses via specific application examples and student assignments.Index Terms—Algebraic companion form, animation, relaying,time-domain simulation, visualization.I. INTRODUCTIONR ELAYING has always played a very important role in the security and reliability of electric power systems. As the technology advances, relaying has become more sophisticated with many different options for improved protection of the system. It is indisputable that relaying has made significant advances with dramatic beneficial effects on the safety of systems and protection of equipment. Yet, because of the complexity of the system and multiplicity of competing factors, relaying is a challenging discipline.Despite all of the advances in the field, unintended relay operations (misoperations) do occur. Many events of outages and blackouts can be attributed to inappropriate relayingsettings, unanticipated system conditions, and inappropriate selection of instrument transformers. Design of relaying schemes strives to anticipate all possible conditions for the purpose of avoiding undesirable operations. Practicing relay engineers utilize a two-step procedure to minimize the possibility of such events. First, in the design phase, comprehensive analyses are utilized to determine the best relaying schemes and settings. Second, if such an event occurs, an exhaustive post-mortem analysis is performed to reveal the roo t cause of the event and what “was missed” in the design phase. The post-mortem analysis of these events is facilitated with the existing technology of disturbance recordings (via fault disturbance recorders or embedded in numerical relays). This process results in accumulation of experience that passes from one generation of engineers to the next.An important challenge for educators is the training of students to become effective protective relaying engineers. Students must be provided with an understanding of relaying technology that encompasses the multiplicity of the relaying functions, communications, protocols, and automation. In addition, a deep understanding of power system operation and behavior during disturbances is necessary for correct relayin g applications. In today’s crowded curricula, the challenge is to achieve this training within a very short period of time, for example, one semester. This paper presents an approach to meet this challenge. Specifically, we propose the concept of the virtual power system for the purpose of teaching students the complex topic of protective relaying within a short period of time.The virtual power system approach is possible because of two factors: a) recent developments in software engineering and visualization of power system dynamic responses, and b) the new generation of power system digital-object-oriented relays. Specifically, it is possible to integrate simulation of the power system, visualization, and animation of relay response and relay testing within a virtual environment. This approach permits students to study complex operation of power systems and simultaneously observe relay response with precision and in a short time.The paper is organized as follows: First, a brief description of the virtual power system is provided. Next, the mathematical models to enable the features of the virtual power system are presented together with the modeling approach for relays and relay instrumentation. Finally, few samples of applications of this tool for educational purposes are presented.II. VIRTUAL POWER SYSTEMThe virtual power system integrates a number of application software in a multitasking environment via a unified graphical user interface. The application software includes a) a dynamic power system simulator, b) relay objects, c) relay instrumentation objects, and d)animation and visualization objects. The virtual power system has the following features:1) continuous time-domain simulation of the system under study;2) ability to modify (or fault) the system under study during the simulation, and immediately observe the effects of thechanges;3) advanced output data visualization options such as animated 2-D or 3-D displays that illustrate the operation of any device in the system under study.The above properties are fundamental for a virtual environment intended for the study of protective relaying. The first property guarantees the uninterrupted operation of the system under study in the same way as in a physical laboratory: once a system has been assembled, it will continue to operate. The second property guarantees the ability to connect and disconnect devices into the system without interrupting the simulation of the system or to apply disturbances such as a fault. This property duplicates the capability of physical laboratories where one can connect a component to the physical system and observe the reaction immediately (e.g., connecting a new relay to the system and observing the operation of the protective relaying logic, applying a disturbance and observing the transients as well as the relay logic transients, etc.). The third property duplicates the ability to observe the simulated system operation, in a similar way as in a physical laboratory. Unlike the physical laboratory where one cannot observe the internal operation of a relay, motor, etc., the virtual power system has the capability to provide a visualization and animation of the internal “workings” of a relay, motor, etc. This capability to animate and visualize the internal “workings” o f a relay, an instrumentation channel, or any other device has substantial educational value.The virtual power system implementation is based on the MS Windows multidocument-viewarchitecture. Each document object constructs a single solver object, which handles the simulation computations. The simulated system is represented by a set of objects—one for each system device (i.e. generators, motors, transmission lines, relays, etc). The document object can generate any number of view window objects. Two basic view classes are available: a) schematic views and b) result visualization views. Schematic view objects allow the user to define the simulated system connectivity graphically, by manipulating a single line diagram using the mouse. Result visualization views allow the user to observe calculated results in a variety of ways. Several types of result visualization views are supported and will be discussed later.Fig. 1 illustrates the organization of device objects, network solver, and view objects and their interactions. The network solver object is the basic engine that provides the time-domain solution of the device operating conditions. To maintain object orientation, each device isrepresented with a generalized mathematical model of a specific structure, the algebraic companion form (ACF). The mathematics of the algebraic companion form are described in the next section. Implementationwise, the network solver is an independent background computational thread, allowing both schematic editor and visualization views to be active during the simulation. The network solver continuously updates the operating states of the devices and “feeds” all other applications, such as visualization views,etc.The network solver speed is user selected, thus allowing speeding-up or slowing-down the visualization and animation speed. The multitasking environment permits system topology changes, device parameter changes, or connection of new devices (motors, faults) to the system during the simulation. In this way, the user can immediately observe the system response in the visualization views.The network solver interfaces with the device objects. This interface requires at minimum three virtual functions:Initialization: The solver calls this function once before the simulation starts. It initializes all device-dependent parameters and models needed during the simulation.Reinitialization: The solver calls this function any time the user modifies any device parameter. Its function is similar to the initialization virtual function.Time step: The solver calls this function at every time step of the time-domain simulation. It transfers the solution from the previous time step to the device object and updates the algebraic companion form of the device for the next time step (see next section “network solver.”)In addition to the above functions, a device object has a set of virtual functions comprising the schematic module interface. These functions allow the user to manipulate the device within the schematic editor graphical user interface. Specifically,the device diagram can be moved, resized, and copied using the mouse. Also, a function is included in this set, which implements a device parameter editing dialog window which “pops-up” by double clicking on the device icon. Furthermore,the schematic module interface allows for device icons that reflect the device status. For example, a breaker schematic icon can be implemented to indicate the breaker status.Finally, each device class (or a group of device classes) may optionally include a visualization module, consisting of a set of virtual functions that handle the visualization and animation output. The visualization module interface allows for both two-dimensional (2-D) and three-dimensional (3-D) graphics. Presently, 2-D output is implemented via the Windows graphical device interface (GDI) standard. The 3-D output is implemented using the opengraphics library (OpenGL). Both 2-D and 3-D outputs generate animated displays, which are dynamically updated by the network solver to reflect the latest device state. The potential applications of 2-D or 3-D animated visualization objects are only limited by the imagination of the developer. These objects can generate photorealistic renderings of electromechanical components that clearly illustrate their internal operation and can be viewed from any desired perspective,slowed down, or paused for better observation.III. NETWORK SOLVERAny power system device is described with a set of algebraicdifferential-integral equations. These equations are obtained directlyfrom the physical construction of the device. It is alwayspossible to cast these equations in the following general formNote that this form includes two sets of equations, which arenamed external equations and internal equations, respectively.The terminal currents appear only in the external equations.Similarly, the device states consist of two sets: external states[i.e., terminal voltages, v(t)] and internal states [i.e. y(t)]. Theset of (1) is consistent in the sense that the number of externalstates and the number of internal states equals the number of externaland internal equations, respectively.Note that (1) may contain linear and nonlinear terms. Equation(1) is quadratized (i.e., it is converted into a set of quadraticequations by introducing a series of intermediate variables and expressing the nonlinear components in terms of a series of quadratic terms). The resulting equations are integrated using a suitable numerical integration method. Assuming an integration time step h, the result of the integration is given with a second-order equation of the formwhere , are past history functions.Equation (2) is referred to as the algebraic companion form (ACF) of the device model. Note that this form is a generalizationof the resistive companion form (RCF) that is used by the EMTP [3]. The difference is that the RCF is a linear model that represents a linearized equivalent of the device while the ACF is quadratic and represents the detailed model of the device.The network solution is ob tained by application of Kirchoff’s current law at each node of the system (connectivity constraints). This procedure results in the set of (3). To these equations, the internal equations are appended resulting to the following set of equations:(3)internal equations of all devices (4)where is a component incidence matrix withif node of component is connected to node otherwise is the vector of terminal currents of component k.Note that (3) correspond one-to-one with the external system states while (4) correspond one-to-one with the internal system states. The vector of component k terminal voltages is related to the nodal voltage vector by(5)Upon substitution of device (2), the set of (3) and (4)become a set of quadratic equations (6)where x(t) is the vector of all external and internal system states.These equations are solved using Newton’s method. Specifically,the solution is given by the following expression(7)where is the Jacobian matrix of (6) and are the values ofthe state variables at the previous iteration.IV. RELAY INSTRUMENTATION MODELINGRelays and, in general, IEDs use a system of instrument transformers to scale the power system voltages and currents into instrumentation level voltages and currents. Standard instrumentation level voltages and currents are 67 V or 115 V and 5 A, respectively. These standards were established many years ago to accommodate the electromechanical relays. Today, the instrument transformers are still in use but because modern relays (and IEDs) operate at much lower voltages, it is necessary to apply an additional transformation to the new standard voltages of 10 or 2 V. This means that the modern instrumentation channel consists of typically two transformations and additional wiring and possibly burdens. Fig. 2 illustrates typical instrumentation channels, a voltage channel and a current channel. Note that each component of the instrumentation channel will introduce an error. Of importance is the net error introduced by all of the components of the instrumentation channel. The overallerror can be defined as follows. Let the voltage or current at the power system be and , respectively. An ideal instrumentation channel will generate a waveform at the output of the channel that will be an exact replica of the waveform at the power system. If the nominal transformation ratio is and for the voltage and current instrumentation channels, respectively, then the output of an “ideal” system and the instrumentation channel error will bewhere the subscript “out” refers to the actual output of the instrumentation channel. The error waveforms can be analyzed to provide the rms value of the error, the phase error, etc.Any relaying course should include the study of instrumentation channels. The virtual power system is used to study the instrumentation error by including an appropriate model of the entire instrumentation channel. It is important to model the saturation characteristics of CTs and PTs, resonant circuits of CCVTs, etc. (see [6]). In the virtual power system, models of instrumentation channel components have been developed. The resulting integrated model provides, with precision, the instrumentation channel error.With the use of animation methods, one can study the evolution of instrumentation errors during transients as well as normal operation.V. PROTECTIVE RELAY MODELINGToday, all new relays are numerical relays. These types of relays can be easily modeled within the virtual power system. Consider, for example, a directional relay. The operation ofthis relay is based on the phase angle between the polarizing voltage and the current. Modeling of this relay then requires that the phase angle between the polarizing voltage and the current be computed. For this purpose, as the power system simulation progresses, the relay model retrieves the instantaneous values of the polarizing voltage and the current. A Fourier transform is applied to the retrieved data (a running time Fourier transform over a user-specified time window). The result will be the phasors of the polarizing voltage and current from which the phase angles are retrieved. The directional element of the relay will trip if the phase angle difference is within the operating region. It should be also self understood that if the relay to be modeled has filters, these filters can be also included in the model.It is important that students be also involved in the design of numerical relays. A typical semester project is to define the functionality of a specific relay and a set of test cases. The student assignment is to develop the code that will mimic the operation of the relay and demonstrate its correct operation for the test cases.The new technology of the virtual power system offers another more practical way to model relays. The virtual power system uses object-oriented programming. As such, it is an open architecture and can accept dynamic link libraries of third parties. A natural extension of the work reported in this paper is to use this feature to interface with commercially available digital “relays.” The word “relay” is in quotation marks to indicate that the relay is simply a digital program that takes inputs of voltages and currents, performs an analysis of these data, applies logic, and issues a decision. This program is an object and can be converted into a dynamic link library. If this DLL is “linked” with the virtual power system, in the sense that the inputs come from the virtual power system, then the specific relay can be evaluated within the virtual environment. The technology for this approach is presently available. Yet, our experience is that relay manufacturers are not presently perceptive in making their “relay” objects available as DLLs that can be interfaced with third-party software.VI. APPLICATIONSThe described virtual environment has been used in a variety of educational assignments. The possible uses are only limited by the imagination of the educator. In this section, we describe a small number of educational application examples.Figs. 3 and 4 illustrate an exercise of studying instrumentation channel performance. Fig. 3 illustrates an example integrated model of a simple power system and the model of an instrumentation channel (voltage). The instrumentation channel consists of a PT, a length of control cable, an attenuator, and an A/D converter (Fig. 3 illustrates the icons of thesecomponents and their interconnection). Fig. 4 illustrates two waveforms: the voltage of phase A of the power system when it is experiencing a fault and the error of the instrumentation channel. The upper part of the figure illustrates the actual voltage of Phase A and the output of the instrumentation channel (multiplied by the nominal transformation ratio). The two traces are quite close. The lower part of the figure illustrates the error between the two waveforms of the upper part of the figure. The two curves illustrate the normalized error at the input of the A/D converter and at the output of the A/D converter. The figure is self-explanatory and a substantial error occurs during the transient of the fault. When the transients subside, the error of the instrumentation channel is relatively small. The intention of this exercise is to study the effects of different parameters of the instrumentation channel.For example, the students can change the length of the control cable and observe the impact on the error. Or in case of a current channel, they can observe the effects of CT saturation on the error of the instrumentation channel, etc.Fig. 5 illustrates the basics of an example application of the virtual power system for visualization and animation of a modified impedance relay. The example system consists of a generator, a transmission line, a step-down transformer, a passive electric load (constant impedance load), an induction motor, and a mechanical load of the motor (fan). A modified distance relay (mho relay) monitors the transmission line. The operation of this relay is based on the apparent impedance that the relay “sees” and the trajectory of this impedance.The visualization object of this relay displays what the relay “sees” during a disturbance in the system and superimposes this information on the relay settings. Typical examples are illustrated in Figs. 6 and 7. The relay monitors the three-phase voltages and currents at the point of its application. The animation model retrieves the information that the relay monitors from the simulator at each time step. Subsequently, it computes the phasors of the voltages and currents as well as the sequence components of these voltages and currents. Fig. 6 illustrates a 2-D visualization of the operation of this relay over a period that encompasses a combined event of an induction motor startup followed by a single-phase fault on the high-voltage side of the transformer. (This example demonstrates the flexibility of the tool to generate composite events that may lead to very interesting responses of the protective relays). The left-hand side of the 2-Dvisualization shows the voltages and currents “seen” by the relay(the snapshot is after the fault has been cleared). The graph also shows the trajectory (history) of the impedance “seen” by the relay. The graph shows the trajectory “seen” over a user-specified time interval preceding present time. The impedance trajectory is superimposed on the trip characteristics of this relay. In this case, the impedance trajectory does not visit thetrip “region” of the relay.Fig. 7 provides the recorded impedance trajectory for the combined event of an induction motor startup followed by a three-phase fault near the low-voltage bus of the transformer. The impedance trajectory is superimposed on the trip characteristics of this relay. In this case, the impedance trajectory does visit the trip “region” of the relay. This example can be extended to more advanced topics. For example, the animated display may also include stability limits for the “swing” of the generator. For this purpose, the stability limits for the particular condition must be computed and displayed.This exercise can be the topic of a term project.Another important protective relaying example is the differential relay. In this example, we present the animated operation of a differential relay scheme for a delta-wye connected transformer with tap changing under load. The example system is shown in Fig. 8. It consists of an equivalent source, a transmission line, a 30-MVA delta-wye connected transformer, a distribution line, and an electric load. A transformer differential relay Fig. 7. Animation of a mho relay for a three phase fault on the 13.8-kV bus. is protecting the transformer. The differential relay has as inputs the transformer terminal currents. A specific implementation of a differential relay visualization is shown in Fig. 9 based on the electromechanical equivalent relay. Note that the 2-D visualization shows t he “operating” coils and “restraining” coils and the currents that flow in these coils at any instant of time. Instantaneous values, rms values, and phasor displays are displayed. Fig. 9 illustrates one snapshot of the system. In reality, as the system operation progresses, this figure is continuously updated, providing an animation effect. The system may operate under steady-state or under transient conditions. The effects of tap changing on the operation of the relay are demonstrated. The importance of this animation module is that one can study the effects of various parameters and phenomena on the operation of the relay. Examples are: a) effects of tap setting. The differential relay settings are typically selected for the nominal tap setting. As the tap setting changes under load, the current in the operating coil changes and may be nonzero even under normal operating conditions. It is very easy to change the tap setting andobserve the operation of the relay in an animated fashion. It is also easy to observe the operation of the relay during a through fault for different values of tap settings. Thus, this tool is very useful in determining the optimal level of percent restraint for the relay. b) effects of inrush currents. One can perform energization simulations of the transformer by various types of breaker-closing schemes. Since the transformer model includes the nonlinear magnetization model of the transformer core, the magnetization inrush currents will appear in the terminals of the transformer and, therefore, in the differential relay. The display of Fig. 9 provides a full picture of the evolutionof the electric currents. One can study the effects of inrush currents by bypassing the even harmonic filters as well as by implementing a number of harmonic filters and observing the effectiveness of the filters. It is important to note that the phenomena involved are very complex, yet a student can study these phenomena indepth and in very short time with the aid of animation and visualization methods.The virtual power system has been also used for testing of physical relays. This application is quite simple. The virtual power system has the capability to export voltage and current waveforms of any event and for any user-selected time period in COMTRADE format. Then, the COMTRADE file is fed into commercial equipment that generates the actual voltages and currents and feeds them into the physical relays. The actual response of the relays is then observed. This application was performed on the premises of a utility with limited access to students.Recently, a major relay manufacturer (SEL) has donated equipment to Georgia Tech and we are in the process of setting up the laboratory for routine use of this function by students. There are numerous other applications of the proposed virtual power system. The pedagogical objective is to instill a deep understanding of protective relaying concepts and problems in the very short time of one semester. The effectiveness of the proposed approach increases as new examples are generated and stored in the database.Aclassical example that demonstrates the effectiveness of the virtual power system is the issue of sympathetic tripping. Usually, this topic requires several lectures and long examples. With the virtual power system, one can very thoroughly teach the concept of sympathetic tripping within onelecture. For example, a simple system with mutually coupled lines can be prepared, with relays at the ends of all lines. Then with a fault in one line, the relays of the healthy line can be visualized and animated. The students can observe that the relays of the healthy line “see” zero-sequence current induced by the fault on another line. And more important, the students can make changes to the designs of the lines and observe the relative effect of design parameters on induced voltages and currents, etc.VII. CONCLUSIONThis paper has discussed and presented the virtual power system and its application for visualization and animation of protective relaying. The virtual power system has proved to be a valuable tool in the instruction of protective relaying courses. It is also an excellent tool for assigning term projects on various aspects of protective relaying. One important feature of the tool is that the user can apply disturbances to the system while the system operates (i.e., faults, load shedding, motor start-up, etc.). The response of the relays is instantaneously observed.。

(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。

电气工程的外文文献(及翻译)

电气工程的外文文献(及翻译)文献一：Electric power consumption prediction model based on grey theory optimized by genetic algorithms本文介绍了一种基于混合灰色理论与遗传算法优化的电力消耗预测模型。

该模型使用时间序列数据来建立模型，并使用灰色理论来解决数据的不确定性问题。

通过遗传算法的优化，模型能够更好地预测电力消耗，并取得了优异的预测结果。

此模型可以在大规模电力网络中使用，并具有较高的可行性和可靠性。

文献二：Intelligent control for energy-efficient operation of electric motors本文研究了一种智能控制方法，用于电动机的节能运行。

该方法提供了一种更高效的控制策略，使电动机能够在不同负载条件下以较低的功率运行。

该智能控制使用模糊逻辑方法来确定最佳的控制参数，并使用遗传算法来优化参数。

实验结果表明，该智能控制方法可以显著降低电动机的能耗，节省电能。

文献三：Fault diagnosis system for power transformers based on dissolved gas analysis本文介绍了一种基于溶解气体分析的电力变压器故障诊断系统。

通过对变压器油中的气体样品进行分析，可以检测和诊断变压器内部存在的故障类型。

该系统使用人工神经网络模型来对气体分析数据进行处理和分类。

实验结果表明，该系统可以准确地检测和诊断变压器的故障，并有助于实现有效的维护和管理。

文献四：Power quality improvement using series active filter based on iterative learning control technique本文研究了一种基于迭代研究控制技术的串联有源滤波器用于电能质量改善的方法。

毕业设计毕业论文电气工程及其自动化外文翻译中英文对照

毕业设计毕业论文电气工程及其自动化外文翻译中英文对照电气工程及其自动化外文翻译中英文对照一、引言电气工程及其自动化是一门涉及电力系统、电子技术、自动控制和信息技术等领域的综合学科。

本文将翻译一篇关于电气工程及其自动化的外文文献，并提供中英文对照。

二、文献翻译原文标题：Electric Engineering and Its Automation作者：John Smith出版日期：2020年摘要：本文介绍了电气工程及其自动化的基本概念和发展趋势。

首先，介绍了电气工程的定义和范围。

其次，探讨了电气工程在能源领域的应用，包括电力系统的设计和运行。

然后，介绍了电气工程在电子技术领域的重要性，包括电子设备的设计和制造。

最后，讨论了电气工程与自动控制和信息技术的结合，以及其在工业自动化和智能化领域的应用。

1. 介绍电气工程是一门研究电力系统和电子技术的学科，涉及发电、输电、配电和用电等方面。

电气工程的发展与电力工业的发展密切相关。

随着电力需求的增长和电子技术的进步，电气工程的重要性日益凸显。

2. 电气工程在能源领域的应用电气工程在能源领域的应用主要包括电力系统的设计和运行。

电力系统是由发电厂、输电线路、变电站和配电网络等组成的。

电气工程师负责设计和维护这些设施，以确保电力的可靠供应。

3. 电气工程在电子技术领域的重要性电气工程在电子技术领域的重要性体现在电子设备的设计和制造上。

电子设备包括电脑、手机、电视等消费电子产品，以及工业自动化设备等。

电气工程师需要掌握电子电路设计和数字信号处理等技术，以开发出高性能的电子设备。

4. 电气工程与自动控制和信息技术的结合电气工程与自动控制和信息技术的结合是电气工程及其自动化的核心内容。

自动控制技术可以应用于电力系统的运行和电子设备的控制，以提高系统的稳定性和效率。

信息技术则可以用于数据采集、处理和传输，实现对电力系统和电子设备的远程监控和管理。

5. 电气工程在工业自动化和智能化领域的应用电气工程在工业自动化和智能化领域的应用越来越广泛。

电气工程毕业设计外文翻译原文

西南交通大学本科毕业设计外文翻译年级:学号:姓名:专业:指导老师xx 年xx、月院系 xxx 专业电气工程及其自动化年级 xx 姓名 xxx题目外文翻译指导教师评语指导教师 (签章)评阅人评语评阅人 (签章) 成绩答辩委员会主任 (签章)年月日目录ABSTRACT (1)I. INTRODUCTION (1)II. DESIGN OF HARDWARE FOR TEMPERATURE CONTROL SYSTEM (2)III. DESIGN OF SIGNAL WIRELESS TRANSMISSION (2)IV. SOFTWARE DESIGN (4)V. CONCLUSION (10)REFERENCES (11)摘要 (12)I 介绍 (12)II 对温度控制系统的硬件是合计 (12)III 设计信号的无线传输 (13)IV 软件设计 (14)V 结论 (18)Design of Temperature Control Device Underground Coal Mine Based on AT89S52ABSTRACTAbstract-Temperature underground coal mine is an important index, especially for mining workers underground. To monitor the temperature effectively, a temperature measurement and control system is necessary to design. Temperature value is displayed on LED screen on line. When temperature value reaches the maximum, conditioning device connected with the opening end of the relay controlled by the MeV will start up. Temperature signal and control information is all transmitted by wireless signal transmission module nRF905. The system program consists of transducer control and display of the temperature value. The control program of transducer is compiled according to its communication protocol. Program of wireless data transmission should be debugged between the data transmission modules. Alarm device is designed to provides effective information to workers when the temperature value is unusual. Thus monitoring of the temperature underground coal mine can be real and effective.Keywords: Index Terms-DS18B20, AT89S52, nRF905, coal mine temperature controlI. INTRODUCTIONThe environment underground coal mine is poor, and various dangers can easily occur. Therefore, in order to ensure safe production of coal mine, it is needed to supervise various parameters underground coal mine, including temperature, pressure, gas, wind speed and distance. Timely monitoring temperatures of some mine key points and coal face is an important monitoring project to guarantee safe production. Moreover, the ultrasonic measurement of distance is usually used in coal mine, to ensure the accuracy of measurement, it is also needed to make accurate temperature measurement. Traditionaltemperature measurement is done by classical isolated sensors, which has some disadvantages as follows: slow reaction rate, high measuring errors, complex installation and debugging and inconvenient long-distance transmission. In this paper intelligent temperature measurement and control is realized by taking DS18B20 temperature sensor and AT89S52 MCU as platform. DS18B20 has some advantages, mainly including digital counting, direct output of the measured temperature value in digital form, less temperature error, high resolution, strong anti-interference ability, long-distance transmission and characteristic of serial bus interface. Comparing with the traditional method of temperature measurement, MCU temperature measurement can achieve storage and analysis of temperature data, remote transmission and so on. DS18B20 sensor is a series of digital single bustemperature sensor made in DALLAS company ofUSA.[I]II. DESIGN OF HARDWARE FOR TEMPERATURE CONTROLSYSTEMThe device is composed of the temperature sensor DS18B20, MCU AT89S52, display module and relay for main fan control. The principle diagram of this hardware is shown in Fig.l.DS18B20 temperature sensor converts the environmental temperature into signed digital signal (with 16 bits complementary code accounting for two bytes), its output pin 2 directly connected with MCU Pl.2. Rl is pull-up resistor and the sensor uses external power supply. Pl.7 is linked to relay and PO is linked to LED display. AT89S52 is the control core of the entire device. Display modules consists of quaternity common-anode LED and four 9012. The read-write of sensor, the display of temperature and the control of relay are completed by program control ofthe system. [2]III. DESIGN OF SIGNAL WIRELESS TRANSMISSION Tested signal is transmitted by wireless mode, as shown in Fig. 1. Wire transmitting of signal underground coal mine has some disadvantages:1) The mineral products are mined by excavation of shaft and tunnel. Meanwhile, there are so many equipments used underground coal mine. Therefore, it is more difficult to wiring in shaft and tunnel, and environmental suitability is poor for wire transmitting of signals;2) Support workers should check up cables for transmitting signals at any moment when combined motion of the coal machine support occurs. Thus, workers' labor intensity is increased;3) The long-distance transmission of sensing element with contact method may lead to larger errors. To reduce errors, the long-distance line driver and safety barrier are needed. Thus, the cost is increased;4) The work load of maintenance underground coal mine is larger.Figure 1. Structure diagram of signal wireless transmission systemBy contrast, adopting wireless data transmission can effectively avoid the above disadvantages. [3]Wireless signal transmission module nRF905 is used in the design. Its characteristics are as follows: Integrated wireless transceiver chip nRF905 works in the ISM band 433/868/915 MHz, consists of a fully integrated frequency modulator, a receiver with demodulator, a power amplifier, a crystal oscillator and a regulator. Its working mode of operation isShock Burst. Preambles and CRC code are automatically generated in the mode, and can easily be programmed through the SPI interface. Current consumption of the module is very low. When the transmit power is +10 dBm, the emission current is 30 rnA and receiving current is 12.2 rnA. It also can enter POWERDOWN model to achieve energy-saving. [4]IV. SOFTWARE DESIGNFor doing the read-write programming for DS18B20, its read-write time sequence should be guaranteed. Otherwise, the result oftemperature measurement will not be read.Figure 2. Software design flow chartTherefore, program design for operation on DS18B20 had better adopt assembly language.[5] Software design flow chart is shown in Fig.2.Structure of Main program for temperature measurement is shown as following: INIT 1820:SETB DINNOPCLRDINMOV RO,#250TSRI: DJNZ RO,TSRISETB DINNOPNOPNOPMOV RO,#60TSR2: DJNZ RO,TSR2JNB PI.0,TSR3LJMPTSR4TSR3: SETB FLAGILJMPTSR5TSR4: CLR FLAG1LJMPTSR7TSR5: MOY RO,#6BHTSR6: DJNZ RO,TSR6TSR7: SETB DINSETB DINRETGET TEMPER:SETB DINLCALL INIT 182018 FLAG1,TSS2RETTSS2: MOY A,#OCCH LCALL WRITE 1820 MOY A,#44HLCALL WRITE 1820 LCALL DELAY LCALL DELAY LCALLDELAY LCALLDELAY LCALL DELAY LCALLDELAY LCALL INIT 1820 MOY A,#OCCH LCALL WRITE 1820 MOY A,#OBEH LCALL WRITE 1820 LCALL READ 1820 RETWRITE 1820:MOY R2,#8CLRCREAD_l 820:MOVR4,#2MOV Rl,#29H REOO: MOV R2,#8 REOl: CLR CSETB DINNOPNOPCLRDINNOPNOPNOPSETB DINMOVR3,#9ADJUST_TEMPER: CLR TEM_BITJNB 47H,AJUSTSETB TEM_BITXRL TEMPER_L,#OFFH MOV A,TEMPER_L ADDA,#OlHMOV TEMPE~L,AXRL TEMPER_H,#OFFH MOV A,TEMPER_H ADDCA,#OOHMOV TEMPER_H,A ADJUST:MOV A,TEMPER_L MOV B,#lOODIVABMOV B_BIT,AMOV A,BMOV B,#lODIVABMOV S_BIT,AMOV G_BIT,BDISP MAIN: LCALL D_DISP LCALL G_DISP LCALL S_DISP LCALL B_DISP MOV A,#OFFH LCALLDISPMOV A,#OFFH LCALL DISPMOV A,#OFFH LCALLDISPMOV A,#OFFH LCALL DISP LCALLDELAY RETD DISP:MOVC,D_BITJC D DISPIMOV A,#03H LCALL DISPRETD DISPl:MOV A,#49H LCALL DISPRETG DISP:MOV A,G_BIT MOV DPTR,#TAB MOVC A,@A+DPTRANLA,#OFEH LCALL DISPRETS DISP:MOV A,S_BITMOV DPTR,#TAB MOVC A,@A+DPTR LCALL DISPRETB DISP:JNB TEM_BIT,B_DIS MOV A,#Ofdh LCALL DISPRETB DIS:JB l8H,B_lMOV A,#Offh LCALL DISPRETB 1: MOV A,#03H LCALL DISPRETDISP: CLRCMOVR2,#8DIS: RRCA MOVDAT,C CLRCLK SETBCLKCLRCLKDJNZ R2,DISRETDELAY: MOV R3,#80hDl: MOV R4,#OfEhDJNZ R4,$DJNZ R3,DlRETTAB:DB 03H,9FH,25H,ODH,99HDB 49H,4IH,IFH,OIH,09HENDV. CONCLUSIONThe performance of measurement-control device mainly depends on the performance of sensing element, the processing circuit and the transmission efficiency of collected data. Digital temperature sensor DSl8B20 and processing chip AT89S52 have characteristics of good technical indexes, and the field operations indicate that circuits system has many advantages, such as accurate data detection, good stability and easy adjustment.After industrial operation test, the system is excellent for worst mine environment, which provides powerful assurance for safe production in the coal industry, and brings good economic and social benefits.REFERENCES[1] WANG Furui, "Single chip microcomputer measurement and control system comprehensive design," Beijing University of Aeronautics and Astronautics Press, 1998.[2] XIA Huguo, "Technology application in automation combined-mining face," Shaanxi Coal, 2007.[3] SHA Zhanyou, "Principle and application of intelligent integrated temperature sensor," Mechanical Industry Publishing House, 2002.[4] CAO Shujuan, HE Yinyong, GUO San-rning, On-line temperaturemeasuring system involving coal mine, Journal of Heilongjiang Instituteof Science & Technology,7(2005)[5] SUN Xiaoqing, XIAO Xingming, WANG Peng, "Design of Measuring System for Rotating Speed of Hoist Based on Virtual Instrument," CoalMine Machinery, 12(2005).基于AT89S52煤矿井下的温度控制装置的设计摘要煤矿井下抽象温度是评价学术期刊的重要指标,特别是对在地下工作的采矿工。

电气工程与自动化专业控制电路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：控制电路设计文献、资料英文题目：Designing Stable Control Loops文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：电气工程与自动化班级：姓名：学号：指导教师：翻译日期： 2017.02.14本科毕业设计外文文献及译文文献、资料题目：Designing Stable Control Loops 文献、资料来源：期刊文献、资料发表（出版）日期：2010.3.25院（部）：信息与电气工程学院专业：电气工程与自动化班级：姓名：学号：指导教师：翻译日期：外文文献：Designing Stable Control LoopsThe objective of this topic is to provide the designer with a practical review of loop compensation techniques applied to switching power supply feedback control. A top-down system approach is taken starting with basic feedback control concepts and leading to step-by-step design procedures, initially applied to a simple buck regulator and then expanded to other topologies and control algorithms. Sample designs are demonstrated with Math cad simulations to illustrate gain and phase margins and their impact on performance analysis.I. I NTRODUCTIONInsuring stability of a proposed power supply solution is often one of the more challenging aspects of the design process. Nothing is more disconcerting than to have your lovingly crafted breadboard break into wild oscillations just as its being demonstrated to the boss or customer, but insuring against this unfortunate event takes some analysis which many designers view as formidable. Paths taken by design engineers often emphasize either cut-and-try empirical testing in the laboratory or computer simulations looking for numerical solutions based on complex mathematical models. While both of these approach a basic understanding of feedback theory will usually allow the definition of an acceptable compensation network with a minimum of computational effort.II. S TABILITY D EFINEDFig. 1. Definition of stabilityFig. 1 gives a quick illustration of at least one definition of stability. In its simplest terms, a system is stable if, when subjected to a perturbation from some source, its response to thatperturbation eventually dies out. Note that in any practical system, instability cannot result in a completely unbounded response as the system will either reach a saturation level –or fail. Oscillation in a switching regulator can, at most, vary the duty cycle between zero and 100% and while that may not prevent failure, it wills ultimate limit the response of an unstable system. Another way of visualizing stability is shown in Fig. 2. While this graphically illustrates the concept of system stability, it also points out that we must make a further distinction between large-signal and small-signal stability. While small-signal stability is an important and necessary criterion, a system could satisfy thisrt quirement and yet still become unstable with a large-signal perturbation. It is important that designers remember that all the gain and phase calculations we might perform are only to insure small-signal stability. These calculations are based upon – and only applicable to –linear systems, and a switching regulator is – by definition –a non-linear system. We solve this conundrum by performing our analysis using small-signal perturbations around a large-signal operating point, a distinction which will be further clarified in our design procedure discussion。

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。

电气专业毕业论文英文文献及翻译(附原文)-基于GPRS的智能交通系统.

毕业设计(论文)外文资料翻译外文原文Traffic Assignment Forecast Model Research in ITS IntroductionThe intelligent transportation system (ITS) develops rapidly along with the city sustainable development, the digital city construction and the development of transportation. One of the main functions of the ITS is to improve transportation environment and alleviate the transportation jam, the most effective method to gain the aim is to forecast the traffic volume of the local network and the important nodes exactly with GIS function of path analysis and correlation mathematic methods, and this will lead a better planning of the traffic network. Traffic assignment forecast is an important phase of traffic volume forecast. It will assign the forecasted traffic to every way in the traffic sector. If the traffic volume of certain road is too big, which would bring on traffic jam, planners must consider the adoption of new roads or improving existing roads to alleviate the traffic congestion situation. This study attempts to present an improved traffic assignment forecast model, MPCC, based on analyzing the advantages and disadvantages of classic traffic assignment forecast models, and test the validity of the improved model in practice.1 Analysis of classic models1.1 Shortcut traffic assignmentShortcut traffic assignment is a static traffic assignment method. In this method, the traffic load impact in the vehicles’ travel is not considered, and the traffic impedance (travel time) is a constant. The traffic volume of every origination-destination couple will be assigned to the shortcut between the origination and destination, while the traffic volume of other roads in this sector is null. Thisassignment method has the advantage of simple calculation; however, unevendistribution of the traffic volume is its obvious shortcoming. Using this assignmentmethod, the assignment traffic volume will be concentrated on the shortcut, which isobviously not realistic. However, shortcut traffic assignment is the basis of all theother traffic assignment methods.1.2 Multi-ways probability assignmentIn reality, travelers always want to choose the shortcut to the destination, whichis called the shortcut factor; however, as the complexity of the traffic network, thepath chosen may not necessarily be the shortcut, which is called the random factor.Although every traveler hopes to follow the shortcut, there are some whose choice isnot the shortcut in fact. The shorter the path is, the greater the probability of beingchosen is; the longer the path is, the smaller the probability of being chosen is.Therefore, the multi-ways probability assignment model is guided by the LOGIT model:∑---=n j ii i F F p 1)exp()exp(θθ (1)Where i p is the probability of the path section i; i F is the travel time of thepath section i; θ is the transport decision parameter, which is calculated by the followprinciple: firstly, calculate the i p with different θ (from 0 to 1), then find the θwhich makes i p the most proximate to the actual i p .The shortcut factor and the random factor is considered in multi-ways probabilityassignment, therefore, the assignment result is more reasonable, but the relationshipbetween traffic impedance and traffic load and road capacity is not considered in thismethod, which leads to the assignment result is imprecise in more crowded trafficnetwork. We attempt to improve the accuracy through integrating the several elements above in one model-MPCC.2 Multi-ways probability and capacity constraint model2.1 Rational path aggregateIn order to make the improved model more reasonable in the application, theconcept of rational path aggregate has been proposed. The rational path aggregate,which is the foundation of MPCC model, constrains the calculation scope. Rationalpath aggregate refers to the aggregate of paths between starts and ends of the trafficsector, defined by inner nodes ascertained by the following rules: the distancebetween the next inner node and the start can not be shorter than the distance betweenthe current one and the start; at the same time, the distance between the next innernode and the end can not be longer than the distance between the current one and theend. The multi-ways probability assignment model will be only used in the rationalpath aggregate to assign the forecast traffic volume, and this will greatly enhance theapplicability of this model.2.2 Model assumption1) Traffic impedance is not a constant. It is decided by the vehicle characteristicand the current traffic situation.2) The traffic impedance which travelers estimate is random and imprecise.3) Every traveler chooses the path from respective rational path aggregate.Based on the assumptions above, we can use the MPCC model to assign thetraffic volume in the sector of origination-destination couples.2.3 Calculation of path traffic impedanceActually, travelers have different understanding to path traffic impedance, butgenerally, the travel cost, which is mainly made up of forecast travel time, travellength and forecast travel outlay, is considered the traffic impedance. Eq. (2) displaysthis relationship. a a a a F L T C γβα++= (2)Where a C is the traffic impedance of the path section a; a T is the forecast traveltime of the path section a; a L is the travel length of the path section a; a F is theforecast travel outlay of the path section a; α, β, γ are the weight value of that threeelements which impact the traffic impedance. For a certain path section, there aredifferent α, β and γ value for different vehicles. We can get the weighted average of α,β and γ of each path section from the statistic percent of each type of vehicle in thepath section.2.4 Chosen probability in MPCCActually, travelers always want to follow the best path (broad sense shortcut), butbecause of the impact of random factor, travelers just can choose the path which is ofthe smallest traffic impedance they estimate by themselves. It is the key point ofMPCC. According to the random utility theory of economics, if traffic impedance is considered as the negativeutility, the chosen probability rs p of origination-destinationpoints couple (r, s) should follow LOGIT model:∑---=n j jrs rs bC bC p 1)exp()exp( (3) where rs p is the chosen probability of the pathsection (r, s);rs C is the traffic impedance of the path sect-ion (r, s); j C is the trafficimpedance of each path section in the forecast traffic sector; b reflects the travelers’cognition to the traffic impedance of paths in the traffic sector, which has reverseratio to its deviation. If b → ∞ , the deviation of understanding extent of trafficimpedance approaches to 0. In this case, all the travelers will follow the path whichis of the smallest traffic impedance, which equals to the assignment results withShortcut Traffic Assignment. Contrarily, if b → 0, travelers ’ understanding error approaches infinity. In this case, the paths travelers choose are scattered. There is anobjection that b is of dimension in Eq.(3). Because the deviation of b should beknown before, it is difficult to determine the value of b. Therefore, Eq.(3) is improvedas follows:∑---=n j OD j OD rsrs C bC C bC p 1)exp()exp(，∑-=n j j OD C n C 11（4） Where OD C is the average of the traffic impedance of all the as-signed paths; bwhich is of no dimension, just has relationship to the rational path aggregate, ratherthan the traffic impedance. According to actual observation, the range of b which is anexperience value is generally between 3.00 to 4.00. For the more crowded cityinternal roads, b is normally between 3.00 and 3.50.2.5 Flow of MPCCMPCC model combines the idea of multi-ways probability assignment andFig.1 Flowchart of MPCC iterative capacity constraint traffic assignment.Firstly, we can get the geometric information of the road network and OD trafficvolume from related data. Then we determine the rational path aggregate with themethod which is explained in Section 2.1.Secondly, we can calculate the traffic impedance of each path section with Eq.(2),which is expatiated in Section 2.3.Thirdly, on the foundation of the traffic impedance of each path section, we cancalculate the respective forecast traffic volume of every path section with improvedLOGIT model (Eq.(4)) in Section 2.4, which is the key point of MPCC.Fourthly, through the calculation processabove, we can get the chosen probability andforecast traffic volume of each path section, but itis not the end. We must recalculate the trafficimpedance again in the new traffic volumesituation. As is shown in Fig.1, because of theconsideration of the relationship between trafficimpedance and traffic load, the traffic impedanceand forecast assignment traffic volume of everypath will be continually amended. Using therelationship model between average speed andtraffic volume, we can calculate the travel timeand the traffic impedance of certain path sect-ionunder different traffic volume situation. For theroads with different technical levels, therelationship models between average speeds totraffic volume are as follows: 1) Highway: 1082.049.179AN V = (5) 2) Level 1 Roads: 11433.084.155AN V = (6) 3) Level 2 Roads: 66.091.057.112AN V = (7) 4) Level 3 Roads: 3.132.01.99AN V = (8) 5) Level 4 Roads: 0988.05.70A N V =(9)Where V is the average speed of the path section;N is the traffic volume of theApath section.At the end, we can repeat assigning traffic volume of path sections with the method in previous step, which is the idea of iterative capacity constraint assignment, until the traffic volume of every path section is stable.译文智能交通交通量分配预测模型介绍随着城市的可持续化发展、数字化城市的建设以及交通运输业的发展，智能交通系统（ITS）的发展越来越快。

电气专业power-factor功率因数大学毕业论文外文文献翻译及原文

毕业设计（论文）外文文献翻译文献、资料中文题目：功率因数文献、资料英文题目：power factor文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：电气班级：姓名：学号：指导教师：翻译日期： 2017.02.14POWER FACTORThe power factor of an AC electric power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit, and is a dimensionless number between 0 and 1 (frequently expressed as a percentage, e.g. 0.5 pf = 50% pf). Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power will be greater than the real power.In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.Linear loads with low power factor (such as induction motors) can be corrected with a passive network of capacitors or inductors. Non-linear loads, such as rectifiers, distort the current drawn from the system. In such cases, active or passive power factor correction may be used to counteract the distortion and raise the power factor. The devices for correction of the power factor may be at a central substation, spread out over a distribution system, or built into power-consuming equipment.Power factor in linear circuits .Instantaneous and average power calculated from AC voltage and current with a unity power factor (φ=0, cosφ=1). Since the blue line is above the axis, all power is real power consumed by the load.Instantaneous and average power calculated from AC voltage and current with a zero power factor (φ=90, cosφ=0). The blue line shows all the power is stored temporarily in the load during the first quarter cycle and returned to the grid during the second quarter cycle, so no real power is consumed.Instantaneous and average power calculated from AC voltage and current with alagging power factor (φ=45, cosφ=0.71). The blue line shows some of the power is returned to the grid during the part of the cycle labelled φ.In a purely resistive AC circuit, voltage and current waveforms are in step (or in phase), changing polarity at the same instant in each cycle. All the power entering the loads is consumed. Where reactive loads are present, such as with capacitors or inductors, energy storage in the loads result in a time difference between the current and voltage waveforms. During each cycle of the AC voltage, extra energy, in addition to any energy consumed in the load, is temporarily stored in the load in electric or magnetic fields, and then returned to the power grid a fraction of a second later in the cycle. The "ebb and flow" of this nonproductive power increases the current in the line. Thus, a circuit with a low power factor will use higher currents to transfer a given quantity of real power than a circuit with a high power factor. A linear load does not change the shape of the waveform of the current, but may change the relative timing (phase) between voltage and current.Circuits containing purely resistive heating elements (filament lamps, strip heaters, cooking stoves, etc.) have a power factor of 1.0. Circuits containing inductive or capacitive elements (electric motors, solenoid valves, lamp ballasts, and others ) often have a power factor below 1.0.Definition and calculationAC power flow has the three components: real power (also known as active power) (P), measured in watts (W); apparent power (S), measured in volt-amperes (V A); and reactive power (Q), measured in reactive volt-amperes (var).The power factor is defined asIn the case of a perfectly sinusoidal waveform, P, Q and S can be expressed as vectors that form a vector triangle such that: If is the phase angle between the current and voltage, then the power factor is equal to the cosine of the angle, , and: Since the units are consistent, the power factor is by definition a dimensionless number between 0 and 1. When power factor is equal to 0, the energy flow is entirely reactive, and stored energy in the load returns to the source on each cycle. When the power factor is 1, all the energy supplied by the source is consumed by the load. Power factors are usually stated as "leading" or "lagging" to show the sign of the phase angle. If a purely resistive load is connected to a power supply, current and voltage will changepolarity in step, the power factor will be unity (1), and the electrical energy flows in a single direction across the network in each cycle. Inductive loads such as transformers and motors (any type of wound coil) consume reactive power with current waveform lagging the voltage. Capacitive loads such as capacitor banks or buried cable generate reactive power with current phase leading the voltage. Both types of loads will absorb energy during part of the AC cycle, which is stored in the device's magnetic or electric field, only to return this energy back to the source during the rest of the cycle. For example, to get 1 kW of real power, if the power factor is unity, 1 kV A of apparent power needs to be transferred (1 kW ÷ 1 = 1 kV A). At low values of power factor, more apparent power needs to be transferred to get the same real power. To get 1 kW of real power at 0.2 power factor, 5 kV A of apparent power needs to be transferred (1 kW ÷0.2 = 5 kV A). This apparent power must be produced and transmitted to the load in the conventional fashion, and is subject to the usual distributed losses in the production and transmission processes. Electrical loads consuming alternating current power consume both real power and reactive power. The vector sum of real and reactive power is the apparent power. The presence of reactive power causes the real power to be less than the apparent power, and so, the electric load has a power factor of less than 1.Power factor correction of linear loadsIt is often desirable to adjust the power factor of a system to near 1.0. This power factor correction (PFC) is achieved by switching in or out banks of inductors or capacitors. For example the inductive effect of motor loads may be offset by locally connected capacitors. When reactive elements supply or absorb reactive power near the load, the apparent power is reduced.Power factor correction may be applied by an electrical power transmission utility to improve the stability and efficiency of the transmission network. Correction equipment may be installed by individual electrical customers to reduce the costs charged to them by their electricity supplier. A high power factor is generally desirable in a transmission system to reduce transmission losses and improve voltage regulation at the load.Power factor correction brings the power factor of an AC power circuit closer to 1 by supplying reactive power of opposite sign, adding capacitors or inductors which act to cancel the inductive or capacitive effects of the load, respectively. For example,the inductive effect of motor loads may be offset by locally connected capacitors. If a load had a capacitive value, inductors (also known as reactors in this context) are connected to correct the power factor. In the electricity industry, inductors are said to consume reactive power and capacitors are said to supply it, even though the reactive power is actually just moving back and forth on each AC cycle.The reactive elements can create voltage fluctuations and harmonic noise when switched on or off. They will supply or sink reactive power regardless of whether there is a corresponding load operating nearby, increasing the system's no-load losses. In a worst case, reactive elements can interact with the system and with each other to create resonant conditions, resulting in system instability and severe overvoltage fluctuations. As such, reactive elements cannot simply be applied at will, and power factor correction is normally subject to engineering analysis.An automatic power factor correction unit is used to improve power factor. A power factor correction unit usually consists of a number of capacitors that are switched by means of contactors. These contactors are controlled by a regulator that measures power factor in an electrical network. To be able to measure power factor, the regulator uses a current transformer to measure the current in one phase.Depending on the load and power factor of the network, the power factor controller will switch the necessary blocks of capacitors in steps to make sure the power factor stays above a selected value (usually demanded by the energy supplier), say 0.9.Instead of using a set of switched capacitors, an unloaded synchronous motor can supply reactive power. The reactive power drawn by the synchronous motor is a function of its field excitation. This is referred to as a synchronous condenser. It is started and connected to the electrical network. It operates at a leading power factor and puts vars onto the network as required to support a system’s voltage or to maintain the system power factor at a specified level.The condenser’s installation and operation are identical to large electric motors. Its principal advantage is the ease with which the amount of correction can be adjusted; it behaves like an electrically variable capacitor. Unlike capacitors, the amount of reactive power supplied is proportional to voltage, not the square of voltage; this improves voltage stability on large networks. Synchronous condensors are often used in connection with high voltage direct current transmission projects or in large industrial plants such as steel mills.Non-sinusoidal componentsNon-linear loads change the shape of the current waveform from a sine wave to some other form. Non-linear loads create harmonic currents in addition to the original (fundamental frequency) AC current. Filters consisting of linear capacitors and inductors can prevent harmonic currents from entering the supplying system.In linear circuits having only sinusoidal currents and voltages of one frequency, the power factor arises only from the difference in phase between the current and voltage. This is "displacement power factor". The concept can be generalized to a total, distortion, or true power factor where the apparent power includes all harmonic components. This is of importance in practical power systems which contain non-linear loads such as rectifiers, some forms of electric lighting, electric arc furnaces, welding equipment, switched-mode power supplies and other devices.A typical multimeter will give incorrect results when attempting to measure the AC current drawn by a non-sinusoidal load; the instruments sense the average value of a rectified waveform. The average response is then calibrated to the effective, RMS value. An RMS sensing multimeter must be used to measure the actual RMS currents and voltages (and therefore apparent power). To measure the real power or reactive power, a wattmeter designed to work properly with non-sinusoidal currents must be used.Measuring power factorPower factor in a single-phase circuit (or balanced three-phase circuit) can be measured with the wattmeter-ammeter-voltmeter method, where the power in watts is divided by the product of measured voltage and current. The power factor of a balanced polyphase circuit is the same as that of any phase. The power factor of an unbalanced polyphase circuit is not uniquely defined.A direct reading power factor meter can be made with a moving coil meter of the electrodynamic type, carrying two perpendicular coils on the moving part of the instrument. The field of the instrument is energized by the circuit current flow. The two moving coils, A and B, are connected in parallel with the circuit load. One coil, A, will be connected through a resistor and the second coil, B, through an inductor, so that the current in coilB is delayed with respect to current in A. At unity power factor, the current in A is in phase with the circuit current, and coil A provides maximum。

毕业设计毕业论文电气工程及其自动化外文翻译中英文对照

理工大学毕业设计（外文翻译材料）学院：专业：学生姓名：指导教师：电气与电子工程学院电气工程及其自动化- .专业文档.Relay protection development present situationAbstract: Reviewed our country electrical power system relay protection technological development process, has outlined the microcomputer relay protection technology achievement, propose the future relay protection technological development tendency will be: Computerizes, networked, protects, the control, the survey, the data communication integration and the artificial intellectualization.Key word: relay protection, present situation development, future development1 relay protection development present situationThe electrical power system rapid development to the relay protection propose unceasingly the new request, the electronic technology, computer technology and the communication rapid development unceasingly has poured into the new vigor for the relay protection technology development, therefore, the relay protection technology is advantageous, has completed the development 4 historical stage in more than 40 years time.After the founding of the nation, our country relay protection discipline, the relay protection design, the relay manufacture industry and the relay protection technical team grows out of nothing, has passed through the path in about 10 years which advanced countries half century passes through. The 50's, our country engineers and technicians creatively absorption, the digestion, have grasped the overseas advanced relay protection equipment performance and the movement technology , completed to have the deep relay protection theory attainments and the rich movement experience relay protection technical team, and grew the instruction function to the national relay protection technical team's establishment. The relay factory introduction has digested at that time the overseas advanced relay manufacture technology, has established our country relay manufacturing- .专业文档.industry. Thus our country has completed the relay protection research, the design, the manufacture, the movement and the teaching complete system in the 60's. This is a time which the mechanical and electrical relay protection prospers, was our countries relay protection technology development has laid the solid foundation.From the end of the 50's, the transistor relay protection was starting to study. In the 60's to the 80's，it is the times which the transistor relay protection vigorous development and widely used. Tianjin University and the Nanjing electric power automation plant cooperation research 500kV transistor direction high frequency protection the transistor high frequency block system which develops with the Nanjing electric power automation research institute is away from the protection, moves on the Gezhou Dam 500kV line , finished the 500kV line protection to depend upon completely from the overseas import time.From the 70's, start based on the integration operational amplifier integrated circuit protection to study. Has formed the completely series to at the end of 80's integrated circuit protection, substitutes for the transistor protection gradually. The development, the production, the application the integrated circuit protects which to the beginning of the 90's still were in the dominant position, this was the integrated circuit protection time. The integrated electricity road work frequency conversion quantity direction develops which in this aspect Nanjing electric power automation research institute high frequency protected the vital role, the Tianjin University and the Nanjing electric power automation plant cooperation development integrated circuit phase voltage compensated the type direction high frequency protection also moves in multi- strip 220kV and on the 500kV line.Our country namely started the computer relay protection research from the end of the 70's, the institutions of higher learning and the scientific research courtyard institute forerunner's function. Huazhong University of- .专业文档.Science and Technology, southeast the university, the North China electric power institute, the Xian Jiao tong University, the Tianjin University, Shanghai Jiao tong University, the Chongqing University and the Nanjing electric power automation research institute one after another has all 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 evaluation and in the system the find application, had opened in our country relay protection history the new page, protect the promotion for the microcomputer to pave the way. In the host equipment protection aspect, the generator which southeast the university and Huazhong University of Science and Technology develop loses magnetism protection, the generator protection and the generator? Bank of transformers protection also one after another in 1989、1994 through appraisal and investment movement. The Nanjing electric power automation research institute develops microcomputer line protective device also in 1991 through appraisal. The Tianjin University and the Nanjing electric power automation plant cooperation development microcomputer phase voltage compensated the type direction high frequency protection, the Xian Jiao tong University and the Xuchang Relay Factory cooperation development positive sequence breakdown component direction high frequency protection also one after another in 1993, in 1996 through the appraisal. Here, the different principle, the different type microcomputer line and the host equipment protect unique, provided one batch of new generation of performance for the electrical power system fine, the function has been complete, the work reliable relay protection installment. Along with the microcomputer protective device research, in microcomputer aspect and so on protection software, algorithm has also yielded the very many theories result. May say- .专业文档.started our country relay protection technology from the 90's to enter the time which the microcomputer protected.2 relay protections future developmentThe relay protection technology future the tendency will be to computerizes, networked, the intellectualization, will protect, the control, the survey and the data communication integration development.2.1 computerizesAlong with the computer hardware swift and violent development, the microcomputer protection hardware also unceasingly is developing. The original North China electric power institute develops the microcomputer line protection hardware has experienced 3 development phases: Is published from 8 lists CPU structure microcomputer protection, does not develop to 5 years time to the multi- CPU structure, latter developed to the main line does not leave the module the big modular structure, the performance enhances greatly, obtained the widespread application. Huazhong University of Science and Technology develops the microcomputer protection also is from 8 CPU, develops to take the labor controlling machine core partially as the foundation 32 microcomputers protection.The Nanjing electric power automation research institute from the very beginning has developed 16 CPU is the foundation microcomputer line protection, obtained the big area promotion, at present also is studying 32 protections hardware system. Southeast the university develops the microcomputer host equipment protects the hardware also passed through improved and the enhancement many times. The Tianjin University from the very beginning is the development take more than 16 CPU as the foundation microcomputer line protection, in 1988 namely started to study take 32 digital signals processor (DSP) as the foundation protection, the control, the survey integration microcomputer installment, at present cooperated with- .专业文档.the Zhuhai automatic equipment company develops one kind of function complete 32 big modules, a module was a minicomputer. Uses 32 microcomputers chips only to focus by no means on the precision, because of the precision the a/d switch resolution limit, is surpassed time 16 all is accepts with difficulty in the conversion rate and the cost aspect; 32 microcomputers chips have the very high integration rate more importantly, very high operating frequency and computation speed, very big addressing space, rich command system and many inputs outlet. The CPU register, the data bus, the address bus all are 32, has the memory management function, the memory protection function and the duty transformation function, and (cache) and the floating number part all integrates the high speed buffer in CPU.The electrical power system the request which protects to the microcomputer enhances unceasingly, besides protection basic function, but also should have the large capacity breakdown information and the data long-term storage space, the fast data processing function, the formidable traffic capacity, with other protections, the control device and dispatches the networking by to share the entire system data, the information and the network resources ability, the higher order language programming and so on. This requests the microcomputer protective device to have is equal to a pc machine function. In the computer protection development initial period, once conceived has made the relay protection installment with a minicomputer. At that time because the small machine volume big, the cost high, the reliability was bad, this tentative plan was not realistic. Now, with the microcomputer protective device size similar labor controlling machine function, the speed, the storage capacity greatly has surpassed the same year small machine, therefore, made the relay protection with complete set labor controlling machine the opportunity already to be mature, this will be one of development directions which the microcomputer protected. The- .专业文档.Tianjin University has developed the relay protection installment which Cheng Yong tong microcomputer protective device structure quite same not less than one kind of labor controlling machine performs to change artificially becomes. This kind of equipment merit includes: has the 486pc machine complete function, can satisfy each kind of function request which will protect to current and the future microcomputer. size and structure and present microcomputer protective device similar, the craft excellent, quakeproof, guards against has been hot, guards against electromagnetic interference ability, may move in the very severe working conditions, the cost may accept. Uses the STD main line or the pc main line, the hardware modulation, may select the different module willfully regarding the different protection, the disposition nimble, and is easy to expand.Relay protection installment, computerizes is the irreversible development tendency. How but to satisfies the electrical power system request well, how further enhances the relay protection the reliability, how obtains the bigger economic efficiency and the social efficiency, still must conduct specifically the thorough research.2.2 networkedThe computer network has become the information age as the information and the data communication tool the technical prop, caused the human production and the social life appearance has had the radical change. It profoundly is affecting each industry domain, also has provided the powerful means of communication for each industry domain. So far, besides the differential motion protection and the vertical association protection, all relay protections installment all only can respond the protection installment place electricity spirit. The relay protection function also only is restricted in the excision breakdown part, reduces the accident to affect the scope. This mainly is because lacks the powerful data communication method. Overseas already had proposed the system protection concept, this in mainly referred- .专业文档.to the safe automatic device at that time. Because the relay protection function not only is restricted in the excision breakdown part and the limit accident affects the scope (this is most important task), but also must guarantee the entire system the security stable movement. This requests each protection unit all to be able to share the entire system the movement and the breakdown information data, each protection unit and the superposition brake gear in analyze this information and in the data foundation the synchronized action, guarantees the system the security stable movement. Obviously, realizes this kind of system protection basic condition is joins the entire system each main equipment protective device with the computer network, that is realization microcomputer protective device networked. This under the current engineering factor is completely possible.Regarding the general non- system protection, the realization protective device computer networking also has the very big advantage. The relay protection equipment can obtain system failure information more, then to the breakdown nature, the breakdown position judgment and the breakdown distance examination is more accurate. Passed through the very long time to the auto-adapted protection principle research, also has yielded the certain result, but must realize truly protects to the system movement way and the malfunction auto-adapted, must obtain the more systems movement and the breakdown information, only then realization protection computer networked, can achieve this point.Regarding certain protective device realization computer networking also can enhance the protection the reliability. The Tianjin University in 1993 proposed in view of the future Three Gorges hydroelectric power station 500kv ultrahigh voltage multi-return routes generatrix one kind of distributional generatrix protection principle, developed successfully this kind of equipment initially. Its principle is disperses the traditional central- .专业文档.generatrix protection certain (with to protect generatrix to return way to be same) the generatrix protection unit, the dispersible attire is located in on various return routes protection screen, each protection unit joins with the computer network, each protection unit only inputs this return route the amperage, after transforms it the digital quantity, transmits through the computer network for other all return routes protection unit, each protection unit acts according to this return route the amperage and other all return routes amperage which obtains from the computer network, carries on the generatrix differential motion protection the computation, if the computed result proof is the generatrix interior breakdown then only jumps the book size return route circuit breaker, Breakdown generatrix isolation. When generatrix area breakdown, each protection unit all calculates for exterior breakdown does not act. This kind the distributional generatrix protection principle which realizes with the computer network has the high reliability compared to the traditional central generatrix protection principle. Because if a protection unit receives the disturbance or the miscalculation when moves by mistake, only can wrongly jump the book size return route, cannot create causes the generatrix entire the malignant accident which excises, this regarding looks like the Three Gorges power plant to have the ultrahigh voltage generatrix the system key position to be extremely important.By above may know, microcomputer protective device may enhance the protection performance and the reliability greatly, this is the microcomputer protection development inevitable trend.2.3 protections, control, survey, data communication integrationsIn realization relay protection computerizing with under the condition, the protective device is in fact a high performance, the multi-purpose computer, is in an entire electrical power system computer network intelligent terminal. It may gain the electrical power system movement and- .专业文档.breakdown any information and the data from the net, also may protect the part which obtains it any information and the data transfer for the network control center or no matter what a terminal. Therefore, each microcomputer protective device not only may complete the relay protection function, moreover in does not have in the breakdown normal operation situation also to be possible to complete the survey, the control, the data communication function that is realization protection, control, survey, data communication integration.At present, in order to survey, the protection and the control need, outdoor transformer substation all equipment, like the transformer, the line and so on the secondary voltage, the electric current all must use the control cable to direct to . Lays the massive control cable not only must massively invest, moreover makes the secondary circuit to be extremely complex. But if the above protection, the control, the survey, the data communication integration computer installation, will install in outdoor transformer substation by the protection device nearby, by the protection device voltage, the amperage is changed into after this installment internal circulation the digital quantity, will deliver through the computer network, then might avoid the massive control cable. If takes the network with the optical fiber the transmission medium, but also may avoid the electromagnetic interference. Now the optical current transformer (OTA) and the optical voltage transformer (OTV) in the research trial stage, future inevitably obtained the application in the electrical power system. In uses OTA and in the OTV situation, the protective device should place is apart from OTA and the OTV recent place, that is should place by the protection device nearby. OTA and the OTV light signal inputs after this integration installment in and transforms the electrical signal, on the one hand serves as the protection the computation judgment; On the other hand took the survey quantity, delivers through the network. May to deliver from through the network by the- .专业文档.protection device operation control command this integrated installment, carries out the circuit breaker operation from this the integrated installment. In 1992 the Tianjin University proposed the protection, the control, the survey, the correspondence integration question, and has developed take the tms320c25 digital signal processor (DSP) as a foundation protection, the control, the survey, the data communication integration installment.2.4 intellectualizationsIn recent years, the artificial intelligence technology like nerve network, the genetic algorithms, the evolution plan, the fuzzy logic and so on all obtained the application in electrical power system each domain, also started in the relay protection domain application research. The nerve network is one non-linear mapping method, very many lists the complex non-linear problem with difficulty which the equation or solves with difficulty, the application nerve network side principle may be easily solved. For example exhibits in the situation in the transmission line two sides systems electric potential angle to occur after the transition resistance short-circuits is a non-linear problem, very difficult correctly to make the breakdown position from the protection the distinction, thus creates moves by mistake or resists to move; If thinks after the network method, passes through the massive breakdowns sample training, so long as the sample centralism has fully considered each kind of situation, then in breaks down time any all may correctly distinguish. Other likes genetic algorithms, the evolution plan and so on also all has its unique solution complex question the ability. May cause the solution speed these artificial intelligence method suitable unions to be quicker? The Tianjin University carries on the nerve network type relay protection from 1996 the research, has yielded the preliminary result. May foresee, the artificial intelligence technology must be able to obtain the application in the relay protection domain, by solves the problem which solves with difficulty with the conventional method.- .专业文档.3 conclusionsSince the founding of China's electric power system protection technology has undergone four times. With the rapid development of power systems and computer technology, communications technology, relay technology faces the further development of the trend. Domestic and international trends in the development of protection technologies: computerization, networking, protection, control, measurement, data communications integration and artificial intelligence, which made protection workers difficult task, but also opened up the activities of vast.- .专业文档.继电保护发展现状摘要：回顾我国电力系统继电保护技术的发展过程，概述了微机继电保护技术成果，提出了未来继电保护技术的发展趋势将是：计算机化，网络化，保护，控制，调查，数据通信一体化和人工智能化。

电气英文文献+翻译

电气专业本科毕业设计英文翻译学院(部)：电气与信息工程学院专业班级：电气08-6班学生姓名：**指导教师：胡业林教授年月日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 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 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 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 tothe 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, 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 networkconstruction, 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.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。

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