电气专业英语课文翻译
电气工程及自动化专业英语考试翻译课文Electric Power Systems 电力系统3.1
Section 1 Introduction 第一节介绍The modern society depends on the electricity supply more heavily than ever before.现代社会比以往任何时候对电力供应的依赖更多。
It can not be imagined what the world should be if the electricity supply were interrupted all over the world. 如果中断了世界各地的电力供应，无法想像世界会变成什么样子Electric power systems (or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world. 电力系统（或电力能源系统），提供电力到现代社会，已成为产业界的不可缺少的组成部分。
The first complete electric power system (comprising a generator, cable, fuse, meter, and loads) was built by Thomas Edison –the historic Pearl Street Station in New York City which began operation in September 1882. 托马斯爱迪生建立了世界上第一个完整的电力系统（包括发电机，电缆，熔断器，计量，并加载）它就是位于纽约市具有历史意义的珍珠街的发电厂始于1882年9月运作。
This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius. The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system. 这是一个直流系统，由一个蒸汽发动机驱动的直流发电机其供电面积约1.5公里至59范围内的客户。
电气工程及其自动化专业英语第6章6-3翻译
Section 3 Operation and Control of Power SystemsThe purpose of a power system is to deliver the power the customers require in real time, on demand, within acceptable voltage and frequency limits, and in a reliable and economic manner. In normal operation of a power system, the total power generation is balanced by the total load and transmission losses. The system frequency and voltages on all the buses are within the required limits, while no overloads on lines or equipment are resulted. However, loads are constantly changed in small or large extents, so some control actions must be applied to maintain the power system in the normal and economic operation state.Optimal economic operationIt is an important problem how to operate a power system to supply all the (complex) loads at minimum cost. The basic task is to consider the cost of generating the power and to assign the allocation of generation ( P Gi) to each generator to minimize the total "production cost" while satisfying the loads and the losses on the transmission lines. The total cost of operation includes fuel, labor, and mainte nance costs, but for simplicity the only variable costs usually considered are fuel costs. The fuel-cost curves for each generating unit are specified, the cost of the fuel used per hour is defined as a function of the generator power output. When hydro-generation is not considered, it is reasonable to choose the PGi on an instantaneous basis (ie always to minimize the present production cost rate). With hydro-generation, however, in dry periods, the replenishment of the water supply may be a problem. The water used today may not be available in the future when its use might be more advantageous. Even without the element of the prediction involved, the problem of minimizing production cost over time becomes much more complicated.It should be mentioned that economy of operation is not the only possible consideration. If the "optimal" economic dispatch requires all the power to be imported from a neighboring utility through a single transmission link, considerations of system security might preclude that solution . When water used for hydro-generation is also used for irrigation, nonoptimal releases of water may be required. Under adverse atmospheric conditions it may be necessary to limit generation at certain fossil-fuel plants to reduce emissions.In general, costs, security and emissions are all areas of concern in power plant operation, and in practice the system is operated to effect a compromise between the frequently conflicting requirements.Power system controlPower system control is very important issue to maintain the normal operation of a system. System voltage levels, frequency, tie-line flows, line currents, and equipment loading must be kept within limits determined to be safe in order to provide satisfactory service to the power system customers.V oltage levels, line currents, and equipment loading may vary from location to location within a system, and control is on a relatively l ocal basis. For example, generator voltage is determined by the field current of each particular generating unit; however, if the generator voltages are not coordinated, excess var flows will result. Similarly, loading on individual generating units is determined by the throttle control on thermal units or the gate controls on hydro-units. Each machine will respond individually to the energy input to its prime mover. Transmission line loadings are affected by power input from generating units and their loadings, the connected loads, parallel paths for power to flow on other lines, and their relative impedances.Active power and frequency controlFor satisfactory operation of a power system, the frequency should remain nearly constant. Relatively close control of frequency ensures constancy of speed of induction and synchronous motors. Constancy of speed of motor drives is particularly important for satisfactory performance of all the auxiliary drives associated with the fuel, the feed-water and the combustion air supply systems. In a network, considerable drop in frequency could result in high magnetizing currents in induction motors and transfor mers . The extensive use of electric clocks and the use of frequency for other timing purpose require accurate maintenance of synchronous time which is proportional to integral of frequency. As a consequence, it is necessary to regulate not only the frequency itself but also its integral. The frequency of a system is dependant on active power balance. As frequency is a common factor throughout the system, a change in active power demand at one point is reflected throughout the system by a change in frequency. Because there are many generators supplying power into the system, some means must be provided to allocate change in demand to the generators. A speed governor on each generating unit provides the primary speed control function, while supplementary control originating at a central control center allocates generation.In an interconnected system with two or more independently controlled areas, in addition to control of frequency, the generation within each area has to be controlled so as to maintain scheduled power interchange. The control of generation and frequency is commonly referred to as load-frequency control (LFC).The control measures of power and frequency include:（1）Regulation of the generator's speed governor（2）Underfrequency load shedding（3）Automatic generation control (AGC)AGC is an effective means for power and frequency control in large-scale power systems. In an interconnected power system, the primary objectives of AGC are to regulate frequency to the specified nominal value and to maintain the interchange power between control areas at the scheduled values by adjusting the output of the selected generators. This function is commonly referred to as load-frequency control . A secondary objective is to distribute the required change in generation among units to minimize operating costs.In an isolated power system, maintenance of interchange power is not an issue. Therefore, the function of AGC is to restore frequency to the specified nominal value. This is accomplished by adding a reset or integral control which acts on the load reference setting of the governors of unit on AGC. The integral control action ensures zero frequency error in the steady state. The supplementary generation control action is much slower than the primary speed control action. As such it takes effect after the primary speed control (which acts on all units on regulation) has stabilized the system frequency. Thus, AGC adjusts load reference settings of selected units, and hence their output power, to override the effects of the composite frequency regulation characteristics of the power system In so doing, it restores the generation of all other units not on AGC to scheduled values.Reactive power and voltage controlFor efficient and reliable operation of power systems, the control of voltage and reactive power should satisfy the following objectives:（1）V oltages at the terminals of all equipment in the system are within acceptable limits. Both utilityequipment and customer equipment are designed to operate at a certain voltage rating. Prolonged operation of the equipment at voltages outside the allowable range could adversely affect their performance and possibly cause them damage.（2）System stability is enhanced to maximize utilization of the transmission system.（3）The reactive power flow is minimized so as to reduce RI2 and XI2 losses to a practical minimum. This ensures that the transmission system operates efficiently, ie mainly for active power transfer.The problem of maintaining voltages within the required limits is complicated by the fact that the power system supplies power to a vast number of loads and is fed from many generating units. As loads vary, the reactive power requirements of the transmission system vary. Since reactive power can not transmitted over long distances, voltage control has to be effected by using special devices disper sed throughout the system. This is in contrast to the control of frequency which depends on the overall system active power balance.The proper selection and coordination of equipment for controlling reactive power and voltage are among the major challenges of power system engineering.The control of voltage levels is accomplished by controlling the production, absorption, and flow of reactive power at all levels in the system. The generating units provide the basic means of voltage control; the automatic voltage regulators control field excitation to maintain a scheduled voltage level at the terminals of the generators. Additional means are usually required to control voltage throughout the system. The devices used for this purpose may be classified as follows:（1）Sources or sinks of reactive power, such as shunt capacitors, shunt reactors, synchro- nous condensers, and static var compensators (SVCs). （（2）Line reactance compensators, such as series capacitors.。
电气自动化专业英语 翻译 中文译文
电气自动化专业英语（翻译1-3）第一部分：电子技术第一章电子测量仪表电子技术人员使用许多不同类型的测量仪器。
一些工作需要精确测量面另一些工作只需粗略估计。
有些仪器被使用仅仅是确定线路是否完整。
最常用的测量测试仪表有：电压测试仪，电压表，欧姆表，连续性测试仪，兆欧表，瓦特表还有瓦特小时表。
所有测量电值的表基本上都是电流表。
他们测量或是比较通过他们的电流值。
这些仪表可以被校准并且设计了不同的量程，以便读出期望的数值。
1．1安全预防仪表的正确连接对于使用者的安全预防和仪表的正确维护是非常重要的。
仪表的结构和操作的基本知识能帮助使用者按安全工作程序来对他们正确连接和维护。
许多仪表被设计的只能用于直流或只能用于交流，而其它的则可交替使用。
注意：每种仪表只能用来测量符合设计要求的电流类型。
如果用在不正确的电流类型中可能对仪表有危险并且可能对使用者引起伤害。
许多仪表被设计成只能测量很低的数值，还有些能测量非常大的数值。
警告：仪表不允许超过它的额定最大值。
不允许被测的实际数值超过仪表最大允许值的要求再强调也不过分。
超过最大值对指针有伤害，有害于正确校准，并且在某种情况下能引起仪表爆炸造成对作用者的伤害。
许多仪表装备了过载保护。
然而，通常情况下电流大于仪表设计的限定仍然是危险的。
1．2基本仪表的结构和操作许多仪表是根据电磁相互作用的原理动作的。
这种相互作用是通过流过导体的电流引起的（导体放置在永久磁铁的磁极之间）。
这种类型的仪表专门适合于直流电。
不管什么时候电流流过导体，磁力总会围绕导体形成。
磁力是由在永久磁铁力的作用下起反应的电流引起。
这就引起指针的移动。
导体可以制成线圈，放置在永久磁铁磁极之间的枢钮（pivot中心）上。
线圈通过两个螺旋型弹簧连在仪器的端子上。
这些弹簧提供了与偏差成正比的恢复力。
当没有电流通过时，弹簧使指针回复到零。
表的量程被设计来指明被测量的电流值。
线圈的移动（或者是指针的偏移）与线圈的电流值成正比。
电气工程及其自动化专业英语第三章课文翻译
Semiconductor switches are very important and crucial components in power electronic systems.these switches are meant to be the substitutions of the mechanical switches,but they are severely limited by the properties of the semiconductor materials and process of manufacturing. 在电力电子系统，中半导体开关是非常重要和关键部件。
半导体开关将要替换机械开关,但半导体材料的性质和生产过程严重限制了他们。
Switching losses开关损耗Power losses in the power eletronic converters are comprised of the Switching losses and parasitic losses. 电力电子转换器的功率损耗分为开关损耗和寄生损耗the parasitic losses account for the losses due to the winding resistances of the inductors and transformers,the dielectric losses of capacitors,the eddy and the hysteresis losses. 寄生损失的绕组电感器、变压器的阻力、介电损耗的电容器,涡流和磁滞损耗the switching losses are significant and can be managed. 这个开关损耗是非常重要的,可以被处理。
they can be further divided into three components:(a)the on-state losses,(b)the off-state losses and the losses in the transition states. 他们可以分为三个部分: 通态损耗，断态损耗和转换过程中产生的损耗。
电气工程及其自动化专业英语第三章课文翻译
Semiconductor switches are very important and crucial components in power electronic systems.these switches are meant to be the substitutions of the mechanical switches,but they are severely limited by the properties of the semiconductor materials and process of manufacturing. 在电力电子系统，中半导体开关是非常重要和关键部件。
半导体开关将要替换机械开关,但半导体材料的性质和生产过程严重限制了他们。
Switching losses开关损耗Power losses in the power eletronic converters are comprised of the Switching losses and parasitic losses. 电力电子转换器的功率损耗分为开关损耗和寄生损耗the parasitic losses account for the losses due to the winding resistances of the inductors and transformers,the dielectric losses of capacitors,the eddy and the hysteresis losses. 寄生损失的绕组电感器、变压器的阻力、介电损耗的电容器,涡流和磁滞损耗the switching losses are significant and can be managed. 这个开关损耗是非常重要的,可以被处理。
they can be further divided into three components:(a)the on-state losses,(b)the off-state losses and the losses in the transition states. 他们可以分为三个部分: 通态损耗，断态损耗和转换过程中产生的损耗。
电气专业中英文翻译
The report concludesThe report mainly collected from the power transmission and power system requirements related to the content of these twoareas, and analyze, to understand some of the relevant knowledge.Page2 Electrical Energy Transmission（电能输送）1 English textFrom reference 1Growing populations and industrializing countries create huge needs for electrical energy. Unfortunately, electricity is not alwaysused in the same place that it is produced, meaning long-distance transmission lines and distribution systems are necessary. Buttransmitting electricity over distance and via networks involves energy loss.So, with growing demand comes the need to minimize this loss to achieve two main goals: reduce resource consumption whiledelivering more power to users. Reducing consumption can be done in at least two ways: deliver electrical energy more efficientlyand change consumer habits.Transmission and distribution of electrical energy require cables and power transformers, which create three types of energy loss:the Joule effect, where energy is lost as heat in the conductor (a copper wire, for example); magnetic losses, where energy dissipates into a magnetic field;the dielectric effect, where energy is absorbed in the insulating material.The Joule effect in transmission cables accounts for losses of about 2.5 % while the losses in transformers range between 1 % and2 % (depending on the type and ratings of the transformer). So, saving just 1 % on the electrical energy produced by a powerplant of 1 000 megawatts means transmitting 10 MW more to consumers, which is far from negligible: with the same energy we cansupply 1 000 - 2 000 more homes.Changing consumer habits involves awareness-raising programmers, often undertaken by governments or activist groups. Simplethings, such as turning off lights in unoccupied rooms, or switching off the television at night (not just putting it into standbymode), or setting tasks such as laundry for non-peak hours are but a few examples among the myriad of possibilities.On the energy production side, building more efficient transmission and distribution systems is another way to go about it. Highefficiency transformers, superconducting transformers and high temperature superconductors are new technologies which promisemuch in terms of electrical energy efficiency and at the same time, new techniques are being studied. These include direct currentand ultra high voltage transmission in both alternating current and direct current modes. Keywords: electrical energy transmissionFrom reference 2Disturbing loads like arc furnaces and thyristor rectifiers draw fluctuating and harmonic currents from the utility grid. These nonsinusoidal currents cause a voltage drop across the finite internal grid impedance, and the voltage waveform in the vicinity becomesdistorted. Hence, the normal operation of sensitive consumers is jeopardized.Active filters are a means to improve the power quality in distribution networks. In order to reduce the injection of non sinusoidalload currents shunt active filters are connnected in parallel to disturbing loads (Fig. 1). The active filter investigated in this projectconsists of a PWM controlled three-level VSI with a DC link capacitor.The VSI is connected to the point of common coupling via atransformer. The configuration is identical with an advanced static var compensator.The purpose of the active filter is to compensate transient and harmonic components of the load current so that only fundamentalfrequency components remain in the grid current. Additionally, the active filter may provide the reactive power consumed by theload. The control principle for the active filter is rather straightforward: The load current ismeasured, the fundamental activecomponent is removed from the measurement, and the result is used as the reference for the VSI output current.In the low voltage grid, active filters may use inverters based on IGBTs with switching frequencies of 10 kHz or more. The harmonicsproduced by those inverters are easily suppressed with small passive filters. The VSI can be regarded nearly as an ideally controllablevoltage source. Inmedium voltage applications with power ratings of several MV A, however, the switching frequen cy of today’s VSIsis limited to some hundred Hertz. Modern high power IGCTs can operate at around 1 kHz. Therefore, large passive filters are neededin order to remove the current ripple generated by the VSI. Furthermore, in fast control schemes the VSI no longer represents anideal voltage source because the PWM modulator produces a considerable dead-time. In this project a fast dead-beat algorithm forPWM operated VSIs is developed [1].This algorithm improves the load current tracking performance and the stability of the activefilter. Normally, for a harmonics free current measurement the VSI currentwould be sampled synchronously with the tips of the triangular carriers. Here, the current acquisition is shifted in order to minimizethe delays in the control loop. The harmonics now included in themeasurement can be calculated and subtracted from the VSIcurrent. Thus, an instantaneous current estimation free of harmonics is obtained.Keywords: active filtersFrom reference 3This report provides background information on electric power transmission and related policy issues. Proposals for changing federaltransmission policy before the 111th Congress include S. 539, the Clean Renewable Energy and Economic Development Act,introduced on March 5, 2009; and the March 9, 2009, majority staff transmission siting draft of the Senate Energy and NaturalResources Committee. The policy issues identified and discussed in this report include:Federal Transmission Planning: several current proposals call for the federal government to sponsor and supervise large scale, on-going transmission planning programs. Issues for Congress to consider are the objectives of the planning process (e.g., a focus onsupporting the development of renewable power or on a broader set of transmission goals), determining how much authority newinterconnection-wide planning entities should be granted, the degree to which transmission planning needs to consider non-transmission solutions to power market needs, what resources theexecutive agencies will need to oversee the planning process, and whether the benefits for projects included in the transmissionplans (e.g., a federal permitting option) will motivate developers to add unnecessary features and costs to qualify proposals for theplan.Permitting of Transmission Lines: a contentious issue is whether the federal government should assume from the states the primaryrole in permitting new transmission lines. Related issues include whether Congress should view management and expansion of thegrid as primarily a state or national issue, whether national authority over grid reliability (which Congress established in the EnergyPolicy Act of 2005) can be effectively exercised without federal authority over permitting, if it is important to accelerate theconstruction of new transmission lines (which is one of the assumed benefits of federal permitting), and whether the executiveagencies are equipped to take on the task of permitting transmission lines.Transmission Line Funding and Cost Allocation: the primary issues are whether the the federal government should help pay for newtransmission lines, and if Congress should establish a national standard for allocating the costs of interstate transmission lines toratepayers.Transmission Modernization and the Smart Grid: issues include the need for Congressional oversight of existing federal smart gridresearch, development, demonstration, and grant programs; and oversight over whether the smart grid is actually proving to be agood investment for taxpayers and ratepayers.Transmission System Reliability: it is not clear whether Congress and the executive branch have the information needed to evaluatethe reliability of the transmission system. Congress may also want to review whether the power industry is striking the right balancebetween modernization and new construction as a means of enhancing transmission reliability, and whether the reliability standardsbeing developed for the transmission system are appropriate for a rapidly changing power system. Keywords: electric power transmissionPage3 Requirements of an Electric Supply System(供电系统需求)1 English textFrom reference1Connections to external 330 kV power grids are provided using an open 330 kV switchyard. The plant is connected to theLithuanian power grid using two transmission lines L-454 and L-453, 330 kV each, to the Belorussian power grid using threetransmission lines L-450, L-452 and L-705, and to the Latvian power grid using one transmission line L-451.Connections to external power grids at 110 kV are provided using the first section of the open 110 kV switchyard. The plant isconnected to the Lithuanian power grid using one transmission line “Zarasai” 110 kV, and to the Latvian power grid using onetransmission line L-632.Connections between the open switchyards at 330 kV and 110 kV are established using two coupling autotransformers AT-1 andAT-2, types ATDCTN- 200000/330. Power of each autotransformer is equal to 200 MV×A. The autotransformers have a device forvoltage regulation under load. The device type is RNOA-110/1000. 15 positions are provided to regulate voltage in a range (115 ±6) kV.The open 330 kV switchyard is designed using "4/3" principle (four circuit breakers per three connections) and consists of twosections. Circuit breakers are placed in two rows. The first section of the open switchyard 110 kV is designed using “Double systemof buses with bypass” structure. The second section of open switchyard 110 kV is connected to the first section through twocircuit breakers C101 and C102. The second section has the same design as the first one. The following transmission lines areconnected to the second section: L-Vidzy, L-Opsa, L-Statyba, LDuk Ötas. These transmission lines are intended for district powersupplies, so they are not essential for electric power supply for the plant in-house operation.Air circuit breakers of VNV-330/3150A type are used in the open 330 kV switchyard. Air circuit breakers of VVBK-110B-50/3150U1type are used in open switchyard 110 kV. To supply power loads on voltage level 330 kV and 110 kV, aerial transmission lines areused. Electrical connections of external grids 110 and 330 kV are presented in Fig. 8.1. Keywords: transmission linesFrom reference 2AbstractThis paper addresses sustainability criteria and the associated indicators allowing operationalization of the sustainability concept in the context of electricity supply. The criteria and indicators cover economic,environmental and social aspects. Some selected results from environmental analysis, risk assessment and economic studies areshown. These studies are supported by the extensive databases developed in this work. The applications of multi-criteria analysisdemonstrate the use of a framework that allows decision-makers to simultaneously address the often conflicting socio-economic andecological criteria. “EnergyGame”, the communication-oriented software recently developed by the Paul Scherrer Institute (PSI),provides the opportunity to integrate the central knowledge-based results with subjective value judgments. In this way a sensitivitymap of technology choices can be constructed in an interactive manner. Accommodation of a range of perspectives expressed inthe energy debate, including the concept of sustainable development, may lead to different internal rankings of the options butsome patterns appear to be relatively robust.IntroductionThe public, opinion leaders and decision-makers ask for clear answers on issues concerning the energy sector and electricitygeneration in particular. Is it feasible to phase out nuclear power in countries extensively relying on nuclear electricity supply andsimultaneously reduce greenhouse gas emissions? What are the environmental and economic implications of enhanced uses ofcogeneration systems, renewable sources and heat pumps? How do the various energy carriers compare with respect to accidentrisks? How would internalization of external costs affect the relative competitiveness of the various means of electricity production?What can we expect from the prospective technological advancements during the next two or three decades? Which systems orenergy mixes come closest to the ideal of being cheap, environmentally clean, reliable and at the same time exhibit low accidentrisks?How can we evaluate and rank the current and future energy supply options with respect to their performance on specificsustainability criteria?The Swiss GaBE Project on “Comprehensive Assessment of Energy Systems” provides answers to many issues in the Swiss andinternational energy arena. A systematic, multidisciplinary, bottom-up methodology for the assessment of energy systems, has beenestablished and implemented. It covers environmental analysis, risk assessment and economic studies, which are supported by theextensive databases developed in this work. One of the analysis products are aggregated indicators associated with the varioussustainability criteria, thus allowing a practical operationalization of the sustainability concept. Apart from technical and economicaspects an integrated approach needs to consider also social preferences, which may be done in the framework of multi-criteriaanalysis.Keywords: criteria indicatorsFrom reference 3Mobility of persons and goods is an essential component of the competitiveness of European industry and services as well as anessential citizen right. The goal of the EU's sustainable transport policy is to ensure that our transport systems meet society'seconomic, social and environmental needs.The transport sector is responsible for about 30% of the total final energy consumption and for about 25% of the total CO2emissions. In particular the contribution of road transport is very high (around 80% and 70% respectively). These simple data shedlight on the necessity to move towards a more sustainable transportation system, but also suggest that a technological/systemicrevolution in the field will positively impact the overall world’s sustainable development.From a technological point of view, a lower dependency from not renewable energy sources (i.e. fuel oil) of the road transport isthe main anticipated change. In particular electric engines possibly represent the natural vehicle evolution in this direction. Indeedthey have much higher energy efficiency (around three times that of internal combustion engines, ICE) and do not produce anykind of tailpipe emissions. How the electricity will be supplied to the vehicles is still unpredictable due to the too many existinguncertainties on the future development, but the electrification of the drive train will contribute to having alternative energy pathsto reduce the nearly total dependency on crude oil. In particular, vehicle range and performances allowed by the differentpossibilities will play a key role on the debate.At the moment a great attention is attracted by electric vehicles, both hybrid and not, that will allow users to recharge theirvehicles directly at home. This kind of vehicle can represent a real future alternative to the ICE vehicles in particular for whatconcerns the daily commuting trips (whose range is quite low). It is therefore important to understand what might be the impacton the electric supply system capabilities of this recharging activity.In this light the present study carries out an analysis of this impact for the Province of Milan (of particular relevant due the very highdaily commuting trips) at a 2030 time horizon. Key issue of the analysis is the estimation of a potential market share evolution for theelectric vehicles. The results obtained show that even with a very high future market penetration the impact of the vehicles on theannual energy consumption will be quite negligible. On the contrary they also show that without an appropriate regulation (e.g. theintelligent integration of electric vehicles into the existing power grid as decentralised and flexible energy storage), they couldheavily impact on the daily electric power requirements.Keywords: electric vehicles报告总结本次报告主要从网上收集了电能输送和供电系统的需求这两个方面的相关内容，并对其进行了分析，了解了一些相关知识。
电气专业英语课文翻译
An electric circuit (or network) is an interconnection of physical electrical device. The purpose of electric circuits is to distribute and convert energy into some other forms. Accordingly , the basic circuit components are an energy source (or sources), an energy converter (or converters) and conductors connecting them. 电路（或者网络）是物理电气设备的一种互相连接。
电路的目的是为了将能量分配和转换到另外一种形式中。
因此，基本的电路元件包括电源、电能转换器以及连接它们的导体。
式中。
因此，基本的电路元件包括电源、电能转换器以及连接它们的导体。
An energy source (a primary or secondary cell, a generator and the like) converts chemical, mechanical, thermal or some some other other other forms forms forms of of of energy energy energy into into into electric electric electric energy. energy. An energy energy converter, converter, converter, also also also called called called load load load (such (such (such as as as a a a lamp, lamp, lamp, heating heating appliance or electric motor), converts electric energy into light, heat, mechanical work and so on. 电源（原生电池或者再生电池、发电机等类似装备）将化学能量、机械能量，热能或者其他形式的能量转换成电能。
电气工程专业英语汉语及翻译
电气工程专业英语姓名：吕海龙学号：20080345班级：08电气专业：电气工程及其自动化Electric Devices and SystemsAlthough transformers have no moving parts , they are essential to electromechanical energy conversion . They make it possible to increase or decrease the voltage lever that results in low costs ,and can be distributed and used safely . In addition , they can provide matching of impedances , and regulate the flow of power in a network.When we see a transformer on a utility pole all we is a cylinder with a few w ires sticking out. These wires enter the transformer through bushings that provide isolation between the wires and the tank. Inside the tank these is an iron core linking coils, most probably made with copper, and insulated. The system of insulation is also associated with that of cooling the core/coil assembly. Often the insulation is paper, and the whole assembly may be immersed in insulating oil, used to both increase the dielectric strength of the paper and to transfer beat from the core-coil assembly to the outer walls of the tank to air. Figure shows the cutout of a typical distribution transformer.Few ideal versions of human constructions exist, and the transformer offers no exception. An ideal transformer is based on very simple concepts, and a large number of assumptions. This is the transformer one learns about in high school.Let us take an iron core with infinite permeability and two coils wound around it, one with N1 and the other with N2 turns, as shown in figure. All the magnetic flux is to remain in the iron. We assign sots at one terminal of each coil in the following fashion: if the flux in the core changes, inducing a voltage in the coils, and the dotted terminal of one coil is positive with respect its other terminal, so is the dotted terminal of the other coil. Or, the corollary to this, current into dotted terminals produces flux in the same direction,Assume that somehow a time varying flux is established in the iron. Then the flux linkages in each coil will be. V oltages will be induced in these two coil.On the other hand, currents flowing in the coils are related to the field intensity H. if currents flowing in the direction shown, i1 into the dotted terminal of coil 1, and i2 out of the dotted terminal of coil 2. we recognize that this is practically impossible, but so is the existence of an ideal transformer.Equations describe this ideal transformer, a two port network. The symbol of a network that is defined by these two equations is in the figure. An ideal transformer has an interesting characteristic. A two-port network that contains it and impedances can be replaced by an equivalent other, as discussed below. Consider the circuit in figure. Seen as a two port network. Generally a circuit on a side 1 can be transferred to side 2 by multiplying its component impedances , the voltage sources and the current sources, while keeping the topology the same.To develop the equivalent for a transformer we’ll gradually relax the assumptions that we had first imposed. First we’ll relax the assumption that the permeability of the iron is infinite. In that case equation does not revert to, but rather it becomes where is the reluctance of the path around the core of the transformer and the flux on this path. To preserve the ideal transformer equations as part of our new transformer, we can split i1 to two components: one i1, will satisfy the ideal transformer equation, and the other, i1 will just balance the right hand side. The figure shows this.We can replace the current source, i1 , with something simpler if we remember that the rate of change of flux is related to the induced voltage.Since the current i1 flows through something , where the voltage across it Is proportional to its derivative, we can consider that this something could be an inductance. This idea gives rise tothe equivalent circuit in figure,. Let us now relax the assumption that all the flux has to remain in the iron as shown in figure. Let us call the flux in the iron, magnetizing flux, the flux that leaks out of the core and links only coil 1. since links only coil 1, then it should be related only to the current there, and the same should be true for the second leakage flux.Again for a given frequency, the power losses in the core increase with the voltage. These losses cannot be allowed to exceed limit, beyond which the temperature of the hottest spot in the transformer will rise above the point that will decrease dramatically the life of the insulation. Limits therefore are put to E1 and E2, and these limits are the voltage limits of the transformer.Similarly, winding Joule losses have to be limited, resulting in limits to the currents I1 and I2.Typically a transformer is described by its rated voltages, that give both the limits and turns radio. The ratio of the rated currents is the inverse of the ratio of the voltages if we neglect the magnetizing current. Instead of the transformer rated currents, a transformer is described by its rated apparent power.Under rated conditions, maximum current and voltage, in typical transformers the magnetizing current, does not exceed 1% of the current in the transformer. Its effect therefore in the voltage drop on the leakage inductance and winding resistance is negligible.Under maximum current, total voltage drops on the winding resistances and leakage inductances do not exceed in typical transformer 6% of the rated voltage. The effect therefore of the winding current on the voltages E1 and E2 is small, and their effect on the magnetizing current can be neglected.These considerations allow us to modify the equivalent circuit in figure, to obtain the slightly inaccurate but much more useful equivalent circuits in figures.Adjustable Speed DrivesBy definition, adjustable speed drives of any type provide a means of variably changing speed to better match operating requirements. Such drives are available in mechanical, fluid and electrical typed.The most common mechanical versions use combinations of belts and sheaves, or chains and sprockets, to adjust speed in set, selectable ratios-2:1,4:1,8:1 and so forth. Traction drives, a more sophisticated mechanical control scheme, allow incremental speed adjustments. Here, output speed is varied by changing the contact points between metallic disks, or between balls and cones.Adjustable speed fluid drives provide smooth, stepless adjustable speed control. There are three major types. Hydrostatic drives use electric motors or internal combustion engines as prime movers in combination with hydraulic pumps, which in turn drive hydraulic motors. Hydrokinetic and hydroviscous drives directly couple input and output shafts. Hydrokinetic versions adjust speed by varying the amount of fluid in a vortex that serves as the input-to-output coupler. Hydroviscous drives, also called oil shear drives, adjust speed by controlling oil-film thickness, and therefore slippage, between rotating metallic disk.An eddy current drive, while technically an electrical drive, nevertheless functions much like a hydrokinetic or hydrovidcous fluid drive in that it serves as a coupler between a prime mover and driven load. In an eddy current drive, the coupling consists of a primary magnetic field and secondary fields created by induced eddy currents. They amount of magnetic slippage allowed among the fields controls the driving speed.In most industrial applications, mechanical, fluid or eddy current drives are paired with constant-speed electric motors. On the other hand, solid state electrical drives, create adjustable speed motors, allowing speeds from zero RPM to beyond the motor’s base speed. Controlling the speed of the motor has several benefits, including increased energy efficiency by eliminating energy losses in mechanical speed changing devices. In addition, by reducing, or often eliminating, the need for wear-prone mechanical components, electrical drives foster increased overall system reliability, as well as lower maintenance costs. For these and other reasons, electrical drives are the fastest growing type of adjustable speed drive..There are two basic drive types related to the type of motor controlled-dc and AC. A DC direct current drive controls the speed of a DC motor by varying the armature voltage (and sometimes also the field voltage ). An alternating current drive controls the speed of an AC motor by varying the frequency and voltage supplied to the motor.Direct current drives are easy to apply and technologically straightforward, They work by rectifying AC voltage from the power line to DC voltage, then feeding adjustable voltage to a DC motor. With permanent magnet DC motors, only the armature voltage is controlled. The more voltage supplied, the faster the armature turns. With wound-field motors, voltage must be supplied to both the armature and the field. In industry, the following three types of DC drives are most common, as shown in the figure.Drives: these are named for the silicon controlled rectifiers (also called thyristors ) used to convert AC to controlled voltage DC. Inexpensive and easy to use, these drives come in a variety of enclosures, and in unidirectional or reversing styles.Regenerative SCR Drives: Also called four quadrant drives, these allow the DC motor to provide both motoring and braking torque, Power coming back from the motor during braking is regenerated back to the power line and not lost.Pulse Width Modulated DC Drives: Abbreviated PWM and also called, generically, transistorized DC drives, these provide smoother speed control with higher efficiency and less motor heating, Unlike SCR drives, PWM types have three elements. The first converts AC to DC, the second filters and regulates the fixed DC voltage, and the third controls average voltage by creating a stream of variable width DC pulses. The filtering section and higher level of control modulation account for the PWM drive’s improved performance compared with a common SCR drive.AC drive operation begins in much the same fashion as a DC drive. Alternating line voltage is first rectified to produce DC. But because an AC motor is used, this DC voltage must be changed back, of inverted, to an adjustable-frequency alternating voltage. The drive’s inverter section accomplishes this, In years past, this was accomplished using SCR. However, modern AC drives use a series of transistors to invert DC to adjustable-Frequency AC. An example is shown in figure.This synthesized alternating current is then fed to the AC motor at the frequency and voltage required to produce the desired motor speed. For example, a 60 Hz synthesized frequency, the same as standard line frequency in the United states, produces 100% of rated motor speed. A lower frequency produces a lower speed, and a higher frequency a higher speed. In this way, an AC drive can produce motor speeds from, approximately,15 to200% of a motor’s normally rated RPM-- by delivering frequencies of 9 HZ to 120 Hz, respectively.Today, AC drives are becoming the systems of choice in many industries,. Their use ofsimple and rugged three-phase induction motor means that AC drive systems are the most reliab le and least maintenance prone of all. Plus, microprocessor advancements have enabled the creation of so-called vector drives, which provide greatly enhance response, operation down to zero speed and positioning accuracy. V ector drives, especially when combined with feedback devices such as tachometers, encoders and resolvers in a closed-loop system, are continuing to replace DC drives in demanding applications. An Example is shown in the figure.By far the most popular AC drive today is the pulse width modulated type. Though originally developed for smaller-horsepower applications, PWM is now used in drives of hundreds or even thousands of horsepower—as well as remaining the staple technology in the vast majority of small integral and fractional horsepower ―micro‖ and ―sub-micro‖ AC drives, as shown in the figure.Pulse width modulated refers to the inverter’s ability to vary the output voltage to the motor by altering the width and polarity of voltage pulses, The voltage and frequency are synthesized using this stream of voltage pulses. This is accomplished through microprocessor commands to a series of power semiconductors that serve as on-off switches. Today, these switches are usually IGBTs, of isolated gate bipolar transistor. A big advantage to these devices is their fast switching speed resulting in higher pulse of carrier frequency, which minimizes motor noise.Power semiconductor devicesThe modern age of power electronics began with the introduction of thyristors in the late 1950s. Now there are several types of power devices available for high-power and high-frequency applications. The most notable power devices are gate turn-off thyristor, power darlington transistors, power mosfets, and insulated-gate bipolar transistors. Power semiconductor devices are the most important functional elements in all power conversion applications. The power devices are mainly used as switches to convert power from one form to another. They are used in motor control systems, uninterrupted power supplies, high-voltage dc transmission, power supplies, induction heating, and in many other power conversion applications. A review of the basic characteristics of these power devices is presented in this section.The thyristor, also called a silicon-controlled rectifier, is basically a four-layer three-junction pn device. It has three terminals: anode, cathode, and gate. The device is turned on by applying a short pulse across the gate and cathode. Once the device turns on, the gate loses its control to turn off the device. The turn-off is achieved by applying a reverse voltage across the anode and cathode. The thyristors symbol and its volt-ampere characteristics are shown in the figure. There are basically two classifications of thyristors: converter grade and inverter grade. The difference between a converter-grade and an inverter-grade thyristor is the low turn –off time (on the order of a few microseconds) for the latter. The converter-grade thyristors are slow type and are used in natural commutation (or phase-controlled) applications. Inverter-grade thyristors are used in forced commutation applications such as dc-dc choppers and dc-ac inverters. The inverter-grade thyristors are turned off by forcing the current to zero using an external commutation circuit. This requires additional commutating components, thus resulting in additional losses in the inverter.Thyristors are highly rugged devices in terms of transient currents, di / dt, and dv/dt capability. The forward voltage drop in thyristors is about 1.5 to 2 V, and even at higher currents of the order of 100 A, it seldom exceeds 3 V. While the forward voltage determines the on-state power loss of the device at any given current, the switching power loss becomes a dominating factor affecting the device junction temperature at high operating frequencies. Because of this, themaximum switching frequencies possible using thyristors are limited in comparison with other power devices considered in this section.Thyristors have withstand capability and can be protected by fuses. The nonrepetitive surge current capability for thyristors is about 10 times their rated root mean square current. They must be protected by snubber networks for dv/dt and di/dt effects. If the specified dv/dt is exceeded, thyristors may start conducting without applying a gate pulse. In dc-to-ac conversion applications it is necessary to use an antiparalled diode of similar rating across each main thyristor. Thyristors are available up to 6000 V, 3500 A.Power mosfets are marketed by different manufacturers with differences in internal geometry and with different names such as megamos, hexfet, sipmos, and tmos. They have unique features that make them potentially attractive for switching applications. They are essentially voltage-driven rather than current-driven devices, unlike bipolar transistors.The gate of a mosfet is isolated electrically from the source by a layer of silicon oxide. The gate draws only a minute leakage current of the order of nanoamperes. Hence the gate drive circuit is simple and power loss in the gate control circuit is practically negligible. Although in steady state the gate draws virtually no current, this is not so under transient conditions. The gate-to-source and gate-to-drain capacitances have to be charged and discharged appropriately to obtain the desired switching speed, and the drive circuit must have a sufficiently to output impedance to supply the required charging and discharging currents. The circuit symbol of a power mosfet is shown in the figure.Power mosfets are majority carrier devices, and there is no minority carrier storage time. Hence they have exceptionally fast rise and fall times. They are essentially resistive devices when turned on, while bipolar transistors present a more or less constant over the normal operating range. Power dissipation in mosfets is I, and in bipolar it is Ic, and in bipolar it is Id. At low currents, therefore, a power mosfet may have a lower conduction loss than a comparable bipolar device, but at higher currents, the conduction loss will exceed that of bipolar. Also, the R increases with temperature.An important feature of a power mosfet is the absence of a secondary breakdown effect, which is present in a bipolar transistor, and as a result, it has an extremely rugged switching performance. In mosfets, R increases with temperature, and thus the current is automatically diverted away from the hot spot. The drain body junction appears as an antiparalled diode between source and drain. Thus power mosfet will not support voltage in the reverse direction. Although this in verse diode is relatively fast, it is slow by comparison with the mosfet. Recent devices have the didde recovery time as low as 100 ns. Since mosfet cannot be protected by fuses, an electronic protection technique has to be used.With the advancement in MOS technology, ruggedized MOSF are replacing the conventional MOSEFs. The need to ruggedize power MOSFETs is related to device reliability. If a MOSFET is operating within its specification range at all times, its chances for failing catastrophically are minimal. However, if its absolute maximum rating is exceeded, failure probability increases dramatically. Under actual operating conditions, a MOSFET may be subjected to transients—either externally from the power bus supplying the circuit or from the circuit itself due, for example, to inductive kicks going beyond the absolute maximum ratings. Such conditions are likely in almost every application, and in most cases are beyond a designer’s control. Rugged devices are made to be more tolerant for over-voltage transients. Ruggedness is the ability of aMOSFET to operate in an environment of dynamic electrical stresses, without activating any of the parasitic bipolar junction transistors. The rugged device can withstand higher levels of diode recovery dv/dt and static dv/dt.（单词量：3115）译文：变压器尽管变压器没有旋转的不见，但是它在本质上还是属于几点能量交换设备。
电气工程及其自动化专业英语课文翻译
unit1 taxe A 电力变压器的结构和原理在许多能量转换系统中，变压器是一个不了缺少的原件。
它使得在经济的发电机所产生电能并以最经历的传输电压传输电能，同时对于特定的使用者合适的电压使用电能成为可能。
变压器同样广泛的应用于低功率低电流的电子电路和控制电路中，来执行像匹配电源组抗和负载以求得最大的传输效率。
隔离一个电路与另一个电路在两个电路之间隔离直流电而保证交流电继续通道的功能。
在本质上，变压器是一个由两个或多个绕组通过相互的磁通耦合而组成的，如果这其中的一个绕组，原边连接到交流电压源将产生交流磁通它的幅值决定于原边的电压所提供的电压频率及匝数。
感应磁通将与其他绕组交链，在副边中将感应出一个电压其幅值将取决于副边的匝数及感应磁通量和频率。
通过使原副边匝数比例适应，任何所期望的电压比例或转换比例都可以得到。
变压器工作的本质仅要求存在与两个绕组相交链的时变的感应磁通。
这样的作用也可以发生在通过空气耦合的两组绕组中，但用铁心或其他铁磁材料可以使绕组之间的耦合作用增强，因为一大部分磁通被限制在与两个绕组交链的高磁导率的路径中。
这种变压器通常被称作为心式变压器。
大部分变压器都是这种类型。
以下的讨论几乎全部围绕心事变压器。
为减少铁心中的涡流所产生的损耗，磁路通常由一叠薄的叠片所组成。
如图1.1所示两种常见的结构形式用示意图表示出来。
芯式变压器的绕组绕在两个矩形铁心柱上，壳式变压器的绕组绕在三个铁心柱中间的那个铁心柱上，。
0.14毫米厚的硅钢片通常被用于在低频率低于几百Hz下运行的变压器中，硅钢片具有价格低铁心损耗小，在高磁通密度下，磁导率高的理想性能，能用做高频率低能耗的标准的通讯电路中的小型变压器的铁心是由被称为铁氧体的粉末压缩制成的铁磁合金所构成的。
在这些结构中，大部分的磁通被限制在固定的铁心中与两个绕组相交链。
绕组也产生多余的磁通，像漏磁通，只经过一个绕组和另外的绕组不相交链。
虽然漏磁通只是所有磁通的一小部分，但它在决定变压器的运行情况中起着重要的作用。
电气工程及其自动化专业英语翻译（精选多篇）
电气工程及其自动化专业英语翻译（精选多篇）第一篇：电气工程及其自动化专业英语翻译Electric Power Systems.The modern society depends on the electricity supply more heavily than ever before.It can not be imagined what the world should be if the electricity supply were interrupted all over the world.Electric power systems(or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world.The first complete electric power system(comprising a generator, cable, fuse, meter, and loads)was built by Thomas Edison – the historic Pearl Street Station in New York City which began operation in September 1882.This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius.The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system..Within a few years similar systems were in operation in most large cities throughout the world.With the development of motors by Frank Sprague in 1884, motor loads were added to such systems.This was the beginning of what would develop into one of the largest industries in the world.In spite of the initial widespread use of DC systems, they were almost completely superseded by AC systems.By 1886, the limitations of DC systems were becoming increasingly apparent.They could deliver power only a short distance from generators.To keep transmission power losses(I 2 R)and voltage drops to acceptable levels, voltage levels had to be high for long-distance power transmission.Such high voltages were not acceptable for generation and consumption of power;therefore, a convenient means for voltage transformationbecame a necessity.The development of the transformer and AC transmission by L.Gaulard and JD Gibbs of Paris, France, led to AC electric power systems.In 1889, the first AC transmission line in North America was put into operation in Oregon between Willamette Falls and Portland.It was a single-phase line transmitting power at 4,000 V over a distance of 21 km.With the development of polyphase systems by Nikola Tesla, the AC system became even more attractive.By 1888, Tesla held several patents on AC motors, generators, transformers, and transmission systems.Westinghouse bought the patents to these early inventions, and they formed the basis of the present-day AC systems.In the 1890s, there was considerable controversy over whether the electric utility industry should be standardized on DC or AC.By the turn of the century, the AC system had won out over the DC system for the following reasons:（1）Voltage levels can be easily transformed in AC systems, thusproviding the flexibility for use of different voltages for generation, transmission, and consumption.（2）AC generators are much simpler than DC generators.（3）AC motors are much simpler and cheaper than DC motors.The first three-phase line in North America went into operation in 1893——a 2,300 V, 12 km line in southern California.In the early period of AC power transmission, frequency was not standardized.This poses a problem for interconnection.Eventually 60 Hz was adopted as standard in North America, although 50 Hz was used in many other countries.The increasing need for transmitting large amounts of power over longer distance created an incentive to use progressively high voltage levels.To avoid the proliferation of anunlimited number of voltages, the industry has standardized voltage levels.In USA, the standards are 115, 138, 161, and 230 kV for the high voltage(HV)class, and 345, 500 and 765 kV for the extra-high voltage(EHV)class.In China, the voltage levels in use are 10, 35, 110 for HV class, and 220, 330(only in Northwest China)and500 kVforEHVclass.Thefirst750kVtransmission line will be built in the near future in Northwest China.With the development of the AC/DC converting equipment, high voltage DC(HVDC)transmission systems have become more attractive and economical in special situations.The HVDC transmission can be used for transmission of large blocks of power over long distance, and providing an asynchronous link between systems where AC interconnection would be impractical because of system stability consideration or because nominal frequencies of the systems are different.The basic requirement to a power system is to provide an uninterrupted energy supply to customers with acceptable voltages and frequency.Because electricity can not be massively stored under a simple and economic way, the production and consumption of electricity must be done simultaneously.A fault or misoperation in any stages of a power system may possibly result in interruption of electricity supply to the customers.Therefore, a normal continuous operation of the power system to provide a reliable power supply to the customers is of paramount importance.Power system stability may be broadly defined as the property of a power system that enables it to remain in a state of operating equilibrium under normal operating conditions and to regain an acceptable state of equilibrium after being subjected to a disturbance..Instability in a power system may be manifested in many different ways depending on the system configurationand operating mode.Traditionally, the stability problem has been one of maintaining synchronous operation.Since power systems rely on synchronous machines for generation of electrical power, a necessary condition for satisfactory system operation is that all synchronous machines remain in synchronism or, colloquially “in step”.This asp ect of stability is influenced by the dynamics of generator rotor angles and power-angle relationships, and then referred to “ rotor angle stability ”译文：电力系统现代社会比以往任何时候更多地依赖于电力供应。
(完整版)电气工程及其自动化专业英语第一章课文翻译
第一章第一篇sectiongTwo variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。
Charge and CurrentThe concept of electric charge is the underlying principle for explaining all electrical phenomena. Also, the most basic quantity in an electric circuit is the electric charge. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C).电荷和电流电荷的概念是用来解释所有电气现象的基本概念。
也即，电路中最基本的量是电荷。
电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。
We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. We also know that the charge e on an electron is negative and equal in magnitude to 1.60210×10 19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged.我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。
(完整版)电气工程及其自动化专业英语第二章课文翻译
第二章第一篇To say that we live in an age of electronics is an understatement. From the omnipresent integrated circuit to the equally omnipresent digital computer, we encounter electronic devices and systems on a daily basis. In every aspect of our increasingly technological society— whether it is science, engineering, medicine, music, maintenance, or even espionage—the role of electronics is large, and it is growing.谈论关于我们生活在一个电子学时代的论调是一种空泛的论调。
从无处不在的集成电路到同样无处不在的数字计算机，我们在日常活动中总会遇到电子设备和电子系统。
在我们日益发展的科技社会的方方面面——无论是在科学、工程、医药、音乐、维修方面甚至是在谍报方面——电子学的作用是巨大的，而且还将不断增强。
In general, all of the tasks with which we shall be concerned can be classified as "signal-processing“tasks. Let us explore the meaning of this term一般说来，我们将要涉及到的工作被归结为“信号——处理”工作，让我们来探究这个术语的含义吧。
A signal is any physical variable whose magnitude or variation with time contains information. This information might involve speech and music, as in radio broadcasting, a physical quantity such as the temperature of the air in a room, or numerical data, such as the record of stock market transactions. The physical variables that can carry information in an electrical system are voltage and current. When we speak of "signals", therefore, we refer implicitly to voltages or currents. However, most of the concepts we discuss can be applied directly to systems with different information-carrying variables. Thus, the behavior of a mechanical system (in which force and velocity are the variables) or a hydraulic system (in which pressure and flow rate are the variables) can often be modeled or represented by an equivalent electrical system. An understanding of the behavior of electrical systems, therefore, provides a basis for understanding a much broader range of phenomena. 信号就是其与时间有关的量值或变化包含信息的任何物理变量。
电气工程及其自动化专业英语课文翻译第四章第三节
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由于转动时的压力很大,所以汽轮发电 机的转子必须设计得较小以使其与其它条件 相一致.同时,在考虑振动的情况下转子的 轴向长度受到限制.因此,转子的设计确实 是一个难题,而整个发电机的设计很大程度 上由转子决定.压力很大,工作温度很高以 及运转空间很小,绝缘受很大的旋转压力, 比较高的温度,以及由线圈的热膨胀而产生 的很大的压力的影响.这些因素使低压转子 绕组成为所需要的绕组.汽轮发电机通常被 设计为励磁电压在125伏至375伏之间,励 磁电流通常由与发电机轴同轴转动的励磁机 获得.
第三节 同步电机
同步电机是一种其稳态转速正比于电枢 电流频率的交流电机.多相直流励磁的同步 电机包含一个多相电枢绕组和一个直流励磁 绕组.在同步转速由电枢绕组产生的旋转磁 场与励磁电流产生的励磁磁场同步旋转,于 是产生了一个稳定的转矩.在另外的部分我 们已经给出了一台同步电机的基本的实际工 作原理图,这个原理图着重强调根据其磁场 之间的相互作用而产生转矩的过程.
这一节旨在导出一种定量的理论,根据 这个理论同步电动机和发电机的电气特性以 及机械特性都可以由此确定.在不考虑凸极 转子以及磁饱和的影响下同步电机可视为理 想化.
同步电机可分为隐极转子和凸极转子两 种,隐极转子结构应用于高速汽轮发电机. 其电枢绕组由放置于定子槽中的分层导体组 成.他们通常是三相星形连接绕组,其线电 压超过13800伏,而且通常其功率大小大于 几千千瓦.转子上放有直流励磁绕组.目前 大多数为频率60赫兹的设备而制造的汽轮发 电机是2极3600转/分的发电机.由于高速高 温高压汽轮机的经济性,许多研究和一些富 有开拓性的工作已改进了发电机和汽轮机的 材料与设计,3600转/分电机的最大容量较十 年前已接近翻了一番.
电气工程及其自动化专业英语第五章课文翻译
Most people can formulate a mental picture of a computer, but computers do so many things and come in such a variety of shapes and sizes that it might seem difficult to distill their common characteristics into an all-purpose definition. At its core, a computer is a device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions.Computer input is whatever is put into a computer system. Input can be supplied by a person, by the environment, or by another computer. Examples of the kinds of input that a computer can accept include the words and symbols in a document, numbers for a calculation, pictures, temperatures from a thermostat, audio signals from a microphone, and instructions from a computer program. An input device, such as a keyboard or mouse, gathers input and transforms it into a series of electronic signals for the computer.In the context of computing, data refers to the symbols that represent facts, objects, and ideas. Computers manipulate data in many ways, and we call this manipulation processing. The series of instructions that tell a computer how to carry out processing tasks is referred to as a computer program, or simply a "program." These programs form the software that sets up a computer to do a specific task. In a computer, most processing takes place in a component called the central processing unit (CPU), which is sometimes described as the"brain" of the computer.A computer stores data so that it will be available for processing. Most computers have more than one location for storing data, depending on how the data is being used. Memory is an area of a computer that temporarily holds data that is waiting to be processed, stored, or output. Storage is the area where data can be left on a permanent basis when it is not immediately needed for processing.Output is the results produced by a computer. Some examples of computer output include reports, documents, music, graphs, and pictures. An output device displays, prints, or transmits the results of processing.Computers are versatile machines, which are able to perform a truly amazing assortment of tasks, but some types of computer are better suited to certain tasks than other types of computers. Computers can be categorized as personal computer, handheld computers, workstations, mainframes, supercomputers , and servers.大多数人可以制订一个电脑精神的图片，但电脑做很多事情，出现这样的形状和大小不同，它似乎难以提炼成一个全能的定义，它们的共同特点。
电气工程及其自动化专业英语第6章6-3翻译
Section 3 Operation and Control of Power Systems 第3节操作和控制的电力系统The purpose of a power system is to deliver the power the customers require in real time, on demand, within acceptable voltage and frequency limits, and in a reliable and economic manner. 该系统的目的，权力是为客户提供电力的时间为客户需要实际需求，对，在可接受的电压和频率的限制，在一个可靠和经济的方式。
In normal operation of a power system, the total power generation is balanced by the total load and transmission losses. 在电力系统正常运行的，总发电是平衡的总负荷和传输的损失。
The system frequency and voltages on all the buses are within the required limits, while no overloads on lines or equipment are resulted. 该系统的频率和电压的所有公共汽车都在规定的限额，而没有超载或设备上线造成的。
However, loads are constantly changed in small or large extents, so some control actions must be applied to maintain the power system in the normal and economic operation state. 但是，负载不断变化幅度小或大，所以一些控制行动必须适用于维持在正常和经济运行状态的电力系统。
(完整版)电气工程及其自动化专业英语第一章课文翻译
第一章第一篇sectiongTwo variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。
Charge and CurrentThe concept of electric charge is the underlying principle for explaining all electrical phenomena. Also, the most basic quantity in an electric circuit is the electric charge. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C).电荷和电流电荷的概念是用来解释所有电气现象的基本概念。
也即，电路中最基本的量是电荷。
电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。
We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. We also know that the charge e on an electron is negative and equal in magnitude to 1.60210×10 19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged.我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。
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An electric circuit (or network) is an interconnection of physical electrical device. The purpose of electric circuits is to distribute and convert energy into some other forms. Accordingly, the basic circuit components are an energy source (or sources), an energy converter (or converters) and conductors connecting them.电路（或者网络）是物理电气设备的一种互相连接。
电路的目的是为了将能量分配和转换到另外一种形式中。
因此，基本的电路元件包括电源、电能转换器以及连接它们的导体。
An energy source (a primary or secondary cell, a generator and the like) converts chemical, mechanical, thermal or some other forms of energy into electric energy. An energy converter, also called load (such as a lamp, heating appliance or electric motor), converts electric energy into light, heat, mechanical work and so on.电源（原生电池或者再生电池、发电机等类似装备）将化学能量、机械能量，热能或者其他形式的能量转换成电能。
电能转换器（也称为负载，如灯泡、电热器或者电动机）将电能转换成光、热、机械运动等等。
Events in a circuit can be defined in terms of e.m.f. (or voltage) and current. When electric energy is generated, transmitted and converted under conditions such that the currents and voltages involved remain constant with time, one usually speaks of direct-current (D.C.) circuits.电路属性可以根据电动势和电流来定义。
当电能在产生、传输和变换时，若电路中相关的电流和电压不随时间而变化，我们便称其为直流电路With time-invariant currents and voltages, the magnetic and electric fields of the associated electric plant are also time-invariant. This is the reason why no e.m.f.s of self-(or mutual-)induction appear in D.C. circuits, nor are there any displacement currents in the dielectric surrounding the conductors.在电流和电压时不变的情况下，相关电气设备的电磁场也是时不变的。
这就是为什么直流电路中没有自（互）感电动势、以及围绕在导体附近的电介质没有位移电流。
Fig.1.1 shows in simplified form a hypothetical circuit with a storage battery as the source and a lamp as the load. The terminals of the source and load are interconnected by conductors (generally but not always wires).图1.1给出了一个假设电路的简单形式：一个蓄电池作为电源、以及一个灯泡作为负载。
电源和负载的终端用导体互相连接，通常这种导体是导线，但少数情况下也有例外。
As is seen, the source, load and conductors form a closed conducting path. The e.m.f. of the source causes a continuous and unidirectional current to circulate round this closed path.如图所示，电源、负载和导体构成了一个闭合导电回路。
电源的电动势产生一个连续的单方向电流在闭合回路中流通。
The simple circuit made up of a source, a load and two wires is seldom, if ever, met with in practice. Practical circuits may contain a large number of sources and loads interconnected in a variety of ways.这种由一个电源、一个负载和两根导线组成的简单电路在实践中即使有时能遇到，也是很少见的。
实际的电路包括很多用不同方法连接起来的电源和负载。
To simplify analysis of actual circuits, it is usual to show them symbolically in a diagram called a circuit diagram, which is in fact a fictitious or, rather, idealized model of an actual circuit of network. Such a diagram consists of interconnected symbols called circuit elements or circuit parameters.为了简化分析，通常用电路图来象征性地表示实际的电路。
实际上，电路图是实际电路的一个假设模型，或相当于一个理想模型。
这样的电路图包括电路元件或者电路参数等互联符号。
Two elements are necessary to represent processes in a D.C. circuit. These are a source of e.m.f. E and of internal (or “source”) resistance RS, and the load resistance (whic h includes the resistance of the conductors) R (Fig.1.2).在直流电路中，有两个元件是有必要描绘出来处理的。
这就是电源的电动势E、内阻RS，以及负载电阻R （其中包含了导体电阻）。
Whatever its origin (thermal, contact, etc.), the source e.m.f. E(Fig.1.2(a)) is numerically equal to the potential difference between terminals 1 and 2 with the external circuit open, that is, when there is no current flowing through the source.无论图1.2(a)中的电动势E的原动力是什么（即不论是热的、机械的还是其它什么形式），其大小就等于1、2两端之间的开路电压，也就是电源没有电流通过的情况。
The source e.m.f. is directed from the terminal at a lower potential to that at a higher one. On diagram, this is shown by arrows.电动势从较低电压端指向较高电压端，这在图表中用箭头表示。
When a load is connected to the source terminals (the circuit is then said to be loaded) and the circuit is closed, a current begins to flow round it. Now the voltage between source terminals 1 and 2 (called the terminal voltage) is not equal to its e.m.f. because of the voltage drop VS inside the source, that across the source resistance RS .当一个负载加在电源两端（也就是说电路被加上负载），同时电路闭合，就有电流开始流通。
这时在电源1、2两端之间的电压（称为端电压）不等同于电源的电动势，因为这时电源内阻RS两端将产生电压降VS。
Fig.1.3 shows a typical so-called external characteristic of a loaded source (hence another name is the load characteristic of a source). As is seen, increase of current from zero to I~I1 causes the terminal voltage of the source to decrease linearly图1.3表示带负载电源的一个典型的外特性（由于电源带负载，所以也称为电源的负载特性）。
如图所示，当电流从0增加到I1时，引起电源端电压的线性减小。
In other words, the voltage drop VS across the source resistance rises in proportion to the current. This goes on until a certain limit is reached. Then as the current keeps rising, the proportionality between its value and the voltage drop across the source is upset, and the external characteristic ceases to be linear.This decrease in voltage may be caused by a reduction in the source voltage, by an increase in the internal resistance, or both. The power delivered by a source is given by the equality PS=EI, where PS is the power of the source.电源1、2两端电压的减小可能是由于电源电压的减小或电源内阻的增加引起的，也可能是两种情况共同引起的。