电气工程及其自动化专业英语》课程论文

电气工程及其自动化专业英语介绍Introduction to Electrical Engineering and its Automation1. IntroductionElectrical Engineering and its Automation is a specialized field that combines the principles of electrical engineering with automation technology. It focuses on the design, development, and implementation of electrical systems and their automation for various applications in industries, power generation, communications, and transportation.2. CurriculumThe curriculum of Electrical Engineering and its Automation program is designed to provide students with a strong foundation in electrical engineering principles, automation technology, and practical skills. The courses typically include:2.1 Electrical Engineering Courses- Circuit Theory: This course introduces the fundamental concepts of electrical circuits, including Ohm's Law, Kirchhoff's Laws, and circuit analysis techniques.- Electromagnetic Field Theory: Students learn about the behavior of electromagnetic fields and how they interact with electrical systems.- Power Systems: This course covers the generation, transmission, and distribution of electrical power, as well as power system protection and control.- Digital Electronics: Students study the principles of digital logic circuits and learn to design and analyze digital systems.- Control Systems: This course focuses on the theory and techniques used in the design and analysis of control systems.2.2 Automation Technology Courses- Programmable Logic Controllers (PLCs): Students learn about the programming and application of PLCs, which are widely used in industrial automation.- Industrial Robotics: This course introduces the principles and applications of industrial robots in manufacturing processes.- Human-Machine Interface (HMI): Students study the design and development of user-friendly interfaces for interacting with automated systems.- Industrial Networks: This course covers the communication protocols and network architectures used in industrial automation.3. Laboratory FacilitiesThe Electrical Engineering and its Automation program provides state-of-the-art laboratory facilities to enhance practical learning and research opportunities for students. These facilities include:3.1 Electrical Circuits Laboratory: Equipped with various electrical components and instruments, this lab allows students to conduct experiments related to circuit analysis, electrical measurements, and troubleshooting.3.2 Automation Laboratory: This lab provides hands-on experience with programmable logic controllers, industrial robots, and human-machine interfaces.3.3 Power Systems Laboratory: Students can simulate and analyze power system operations, protection schemes, and control strategies using advanced software tools.4. Career ProspectsGraduates of the Electrical Engineering and its Automation program have diverse career opportunities in various industries, research institutions, and government organizations. Some potential career paths include:4.1 Electrical Engineer: Graduates can work as electrical engineers, involved in the design, installation, and maintenance of electrical systems in industries such as power generation, telecommunications, and transportation.4.2 Automation Engineer: With expertise in automation technology, graduates can work as automation engineers, responsible for designing and implementing automated systems in manufacturing and process industries.4.3 Control Systems Engineer: Graduates can pursue careers as control systems engineers, involved in the design and optimization of control systems for industrial processes and machinery.4.4 Research and Development: Graduates can also pursue research and development roles, working on advanced technologies and innovations in electrical engineering and automation.5. ConclusionThe Electrical Engineering and its Automation program offers a comprehensive education in electrical engineering principles and automation technology. With a strong theoretical foundation and practical skills, graduates are well-equipped to contribute to the advancement of industries and society through the design and implementation of innovative electrical systems and automation solutions.。

关于电气工程专业英语的作文Diving into the realm of electrical engineering is like exploring a vast, intricate web of innovation and technology that powers our modern world. This field, with its heart set on the pulse of progress, is not just about circuits and currents; it's a language of its own, with English at its core, bridging the gap between theory and application.Electrical engineering is a discipline that has evolved dramatically over the decades, and its language has kept pace, incorporating a rich lexicon of terms that describeeverything from the most fundamental components to the most cutting-edge technologies. For students and professionals alike, mastering the English terminology is crucial for understanding the principles that underpin electrical systems, from the microchip to the power grid.In this dynamic field, the ability to communicate effectively in English is paramount. Whether it's discussing the intricacies of a power electronics converter or thedesign of a high-voltage transmission line, precision in language is as important as precision in engineering. English serves as the universal medium for scholarly articles, technical specifications, and international conferences,where the latest research and developments are shared.Moreover, the language of electrical engineering is not static; it evolves with the field. New terms emerge astechnologies advance, such as "smart grid," "renewable energy," and "Internet of Things (IoT)," each reflecting the ongoing expansion of the discipline. Keeping up with these developments requires a commitment to continuous learning and an openness to embracing new concepts and terminologies.The study of electrical engineering English also extends beyond the technical. It encompasses the ability to interpret and create diagrams, to understand and apply mathematical models, and to engage in critical thinking about the implications of new technologies on society and the environment.In essence, the mastery of electrical engineering English is not just about the words; it's about the ideas they represent and the solutions they enable. It's about theability to connect with a global community of engineers, to contribute to a field that is constantly pushing the boundaries of what is possible, and to be part of a conversation that shapes the future of our world.。

Electrical Engineering and Automation Electrical Engineering and Automation was created at forty years ago. AS a new subject, it is relating to many walks of life, small to a switch designed to study aerospace aircraft, has its shadow.Electrical Engineering and Automation of electrical information professional is an emerging field of science, but because of people's daily lives and industrial production is closely related to the extraordinarily rapid development of relatively more mature now. High-tech industry has become an important component of the widely used in industry, agriculture, national defense and other fields, in the national economy is playing an increasingly important role.Worse more, Electrical Engineering and Automation is very hard to learn. The graduate should obtain much knowledge and ability. Such as natural science foundations include more sturdy mathematics, physics, etc, better Humanity, social science basic for sum foreign language for integration capability. Besides the essential technological basic theory knowledge of the originally professional field, mainly include circuit, electric magnetic field theory, electronic technology, information place in system Paying attention to, control theory, computer software andhardware basic theories. And so on.Control theory and electrical network theory is a professional electrical engineering and automation of the base, power electronics technology, computer technology is its main technical means, but also includes a system analysis, system design, system development and system management and decision-making research. There are some characteristics of the profession, that is, combining the strength of power, electrical and electronic technology, software and hardware combined with a cross-disciplinary nature, electricity, electronics, control, computer integrated multi-disciplinary, so that graduates with strong adaptation capacity.Electricity is the most important and convenient energy which the modern society depends on more heavily than ever before. Electric power system, providing electricity to the modern society, has become indispensible components of the industry world. Power system and automation researches on how to produce, transform, transmit, distribute, use, control and manage electricity. It combines the traditional electrotechology with computer science ,power electronics and automation control theory ,with board prospects for development.We quest the principle and structure of power system network in order to improve our system to provide a reliable power supply with acceptable voltages and frequency to the customers. This major contains 3 core curricula--Motor learning, Power system analysis and Relay protection.Motor learning introduces the basic equipments of power system to us such as generators, transformers and motors. It's the basis of the following two curricula.Power system analysis describes the power flow calculation , power system control(one isactive power and frequency control the other is reactive power and voltage control)and power system stability(including small disturbance stability and transient sta...电气10-3班魏学军25号。

电气工程及其自动化专业英语作文范文Electrical Engineering and Automation: An Integral Part of Modern SocietyIntroductionElectrical Engineering and Automation, a discipline that has evolved significantly over the past few decades, has become an integral part of modern society. Its widespread applications in industry, agriculture, national defense, and various other fields have propelled it to a pivotal position in the global economy.Historical PerspectiveThe field of Electrical Engineering and Automation was first established approximately forty years ago. As a relatively new discipline, it has quickly grown to encompass a wide range of subfields and applications. From the design of switches for aerospace aircraft to the development of complex automated systems, its influence is pervasive.Core ComponentsThe core of Electrical Engineering and Automation lies in its ability to integrate electricity, machines, and intelligent systems to automate various tasks. This integration enables efficiency, precision, and safety in a wide range of applications.•Electricity and Machines: Electricity provides the power that drives machines and systems. Understanding the behavior ofelectrical circuits, voltage sources, current sources, andvarious network elements is crucial for the effective designand operation of automated systems.•Automation: Automation refers to the use of technology to control and monitor processes and machines with minimal humanintervention. It relies on sensors, actuators, and intelligentcontrollers to achieve desired outcomes.Challenges and OpportunitiesWhile Electrical Engineering and Automation offers immense opportunities for growth and development, it also poses significantchallenges. The complexity of modern systems requires a high level of technical knowledge and expertise. Additionally, the rapid pace of technological advancement requires constant updating of skills and knowledge.However, these challenges also present opportunities for innovation and growth. As new technologies emerge, there is a need for engineers and technicians who can understand and apply them effectively. This creates opportunities for those with a passion for learning and a willingness to adapt to new challenges.ConclusionIn conclusion, Electrical Engineering and Automation is a dynamic and exciting field that offers immense opportunities for growth and development. Its applications are pervasive, and its influence on society is profound. As we continue to push the boundaries of technology, Electrical Engineering and Automation will play an increasingly important role in shaping our future.。

电气工程及其自动化专业英语介绍Introduction:Electrical Engineering and its Automation is a specialized field that combines the principles of electrical engineering with automation technology. This article aims to provide an overview of this discipline and its importance in various industries.I. Importance of Electrical Engineering and its Automation:1.1 Advancements in technology: Electrical Engineering and its Automation play a vital role in the development of new technologies. It enables the design and implementation of innovative electrical systems and automation solutions.1.2 Efficiency and productivity: By optimizing electrical systems and automating processes, this discipline helps in improving efficiency and productivity in industries such as manufacturing, power generation, and transportation.1.3 Safety and reliability: Electrical Engineering and its Automation ensure the safety and reliability of electrical systems by incorporating protective measures and fault detection mechanisms.II. Key Concepts in Electrical Engineering and its Automation:2.1 Electrical circuits and systems: This field extensively deals with the analysis and design of electrical circuits and systems. It includes topics such as circuit theory, electronic devices, and power systems.2.2 Control systems: Control systems are an integral part of automation. This area focuses on designing algorithms and controllers to regulate and optimize the behavior of dynamic systems.2.3 Programmable Logic Controllers (PLCs): PLCs are widely used in industrial automation. They are programmable devices that control and monitor various processes, ensuring seamless operation and fault detection.III. Applications of Electrical Engineering and its Automation:3.1 Power generation and distribution: Electrical Engineering and its Automation are crucial in the generation, transmission, and distribution of electrical power. It involves designing efficient power systems, grid management, and renewable energy integration.3.2 Industrial automation: This discipline plays a significant role in automating industrial processes, improving efficiency, and reducing human intervention. It includes robotics, motion control, and process automation.3.3 Smart grids and energy management: Electrical Engineering and its Automation contribute to the development of smart grids, enabling efficient energy distribution, load management, and demand response systems.IV. Career Opportunities in Electrical Engineering and its Automation:4.1 Electrical engineer: Graduates in this field can work as electrical engineers, involved in the design, installation, and maintenance of electrical systems and automation solutions.4.2 Automation engineer: Automation engineers focus on designing and implementing control systems, PLC programming, and integrating automation technologies into various industries.4.3 Research and development: Electrical Engineering and its Automation offer ample opportunities for research and development in areas such as renewable energy, power electronics, and advanced control systems.V. Conclusion:In conclusion, Electrical Engineering and its Automation is a dynamic field that combines electrical engineering principles with automation technology. It plays a crucial role in advancing technology, improving efficiency, and ensuring the safety and reliability of electrical systems. Graduates in this field have diverse career opportunities in various industries. As technology continues to evolve, the importance of ElectricalEngineering and its Automation will only increase, making it an exciting and promising field of study.。

电气工程及其自动化专业英语课程论文Document serial number【NL89WT-NY98YT-NC8CB-NNUUT-NUT108】重庆邮电大学移通学院《电气工程及其自动化专业英语》课程论文年级 2012专业电气工程与自动化姓名孙猜胜学号Three-phase asynchronous motorAbstract:The three-phase asynchronous motor is motor's one with single phase asynchronous motor, three-phase asynchronous motor operating performance is good, and can save various the structure to be simple, the manufacture is easy, firm durable, the service is convenient,cost inexpensive ,drag the ability is good,and so on a series of merits. thus becomes in each kind of electrical machinery the outputto be biggest utilizes the broadest one kind of electric motor.Key words:Moror Motor starting Star delta StartingThree-phase asynchronous motor principle:When the stator winding through into the three-phase ac three-phase symmetric arises when a synchronous speed n1 along the stator and rotor round for space in a clockwise rotation magnetic field. Because of a rotating magnetic field rotating speed to n1, rotor conductor of the static beginning, so the rotor conductor will cutthe stator and produce a rotating magnetic field induction emf (induction emf direction DingZe judge with the right hand). Because the child is short circuit loop ends conductor short meet, in therole of the induced emf, will produce the rotor conductor with induction emf direction basic consistent induced current. The rotor current-carrying conductor at stator magnetic field is the role ofthe electromagnetic force (the direction of the force with the left hand DingZe judge). The electromagnetic force of the rotor axis electromagnetic torque, drive along the rotor rotating magnetic field rotation direction.[1]Through the above analysis can be summed up the motor principle: when the three-phase motor stator winding (eachdiffer 120 KWH Angle), ventilation with three-phase ac, will producea rotating magnetic field, the rotating magnetic field cutting rotor winding, and thus to the rotor winding induced current (rotor windingis closed access), load flow of rotor stator conductor under the action of a rotating magnetic field will produce the electromagnetic force, thus in the motor shaft formed on the electromagnetic torque, driving motor rotation, and motor rotation direction and the rotating magnetic field in the same direction.Thestructureofthree-phaseasynchronousmotor:Types of three-phase asynchronous motor, but all kinds of three-phase asynchronous motor is the same basic structure, they are the stator and rotor of these two basic components, the stator and rotor has a certain air gap between. In addition, end caps, bearings, cable boxes, rings and other accessories,1).StatorpartStator is used to generate the rotating magnetic Three-phase motors generally shell, stator core, stator windings and other parts.a.Shell?Three-phase motor casing including base,end caps,bearingcaps,rings,such as junction boxes and comp onentsb. Stator CoreInduction motor stator core is part of the motor circuit from ~ thick coated with a thin insulating paint from silicon,c.ThestatorwindingsThree-phase motor stator windings are part of the circuit,there are three-phase three-phase motor windings,summetrical three-phase current access,it will have a rotating magnetic winding consists of three separate components of the winding, and each has a number of coil windings a phase of each winding, each winding in the space angle difference between the 120 ° electrical[2].2). Rotor parta. Rotor CoreWith mm thick steel from, set in the shaft, the role and the same stator core, on the one hand, as part of the motor magnetic circuit, on the one hand to place the rotor windings.b. Rotor windingsThe rotor winding induction motor winding is divided into two kinds of cage-shaped and which is divided into winding rotor asynchronous motor with cage induction motor.3). Other parts ofOther parts including the cover, fans, etc.Induction motor starting methods:There are several general methods of starting induction motors: full voltage, reduced voltage,wyes-delta,and part winding reduced voltage type can include solid state starters, adjustable frequency drives, and following is the most common method.1).Full voltageThe full voltage starting method, also known as across the line starting, is the easiest method to employ, has the lowest equipment costs, and is the most reliable. This method utilizes a control to close a contactor and apply full line voltage to the motor terminals. This method will allow the motor to generate its highest starting torque and provide the shortest acceleration method also puts the highest strain on the power system due to the high starting currents that can be typically six to seven times the normal full load current of the motor.2).AutotransformerThe motor leads are connected to the lower voltage side of the transformer. The most common taps that are used are 80%, 65%, and 50%. At 50% voltage the current on the primary is 25% of the full voltage locked rotor amps. The motor is started with this reduced voltage,and then after a pre-set condition is reached the connection is switched to line voltage. This condition could be a preset time, current level, bus volts, or motor speed. The change over can be done in either a closed circuit transition, or an open circuit transition method. In the open circuit method the connection to the voltage is severed as it is changed from the reduced voltage to the line level. Care should be used to make sure that there will not be problems from transients due to the switching. This potential problem can be eliminated by using the closed circuit transition. With the closed circuit method there is a continuous Voltage applied to the motor. Another benefit with the autotransformer starting is in possiblelower vibration and noise levels during starting.3).Star delta StartingThis approach started with the induction motor,the structure of each phase of the terminal are placed in the motor teminal box ,This allows the motor star connection in the initial start up,and then re-connected into a triangle run..The initial start time when the voltage is reduced to the original star connection,the startingcurrent and starting torque by 2/3. Depending on the applicationon,the motor switch to the triangle in the rotational speed of between 50% and the maximum be noted that the sameproblems,including the previously mentioned switch method ,if theopen circuit method,the transition may be a transient method isoften used in lesst than 600V motor,the rated voltage and higher are not suitable for star delta motor start method.[3]4).Series Resistor or Reactor StartingThis method is to use a series resistance or place in the motor loop the motor is started, a resistor to limit current and make the motor at the input voltage drop. Therefore plays a role of limitingcurrent at the small motor series resistor startup mode used more frequentlyConclusion:There are many ways asynchronous motor starting, each method hasits own benefits, according to the constraints of powersystems,equipment costs, load the boot device to select the best method.References:[1] Tang Tianhao Fundamentals of Electrical Machines and Drives [M] BeijingChina Machine Press 118-137[2] Wang Liming English for Electrical Engineering and Automation [M] BeijingTsinghua University Press 61-64[3] Stephen Electromechanics [M] America Electronic IndustryPress 340-370。

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 。

(完整word版)电气工程及其自动化专业外语作文A s a student, you will learn to apply related subjects such as computer technology，industrial electronics, instrumentation，electrical machines, robotics，power electronics，and automated control systems.作为一名学生，你将学会运用相关学科,如计算机技术，工业电子，仪器仪表，电器机械，机器人技术，电力电子和自动化控制系统。

Y ou will be able to understand written and oral instructions，as well as design, install, test，modify, troubleshoot，and repair electrical systems.您将能够理解书面和口头说明，以及设计,安装，测试，修改，故障排除和修复电力系统.U pon graduation，students of the Electrical Engineering Technology –Process Automation program can approach industrial electrical and electronic systems from the viewpoint of analysis，technical evaluation, design, and development。

The six—semester program concentrates on the in-depth study of electrical and electronic principles as they apply to automated systems using programmable logic controllers。

Power Supply and Distribution SystemABSTRACT: The basic function of the electric power system is to transport the electric power towardscustomers..The l0kV electric distribution net is a key point that connects the power supply with the electricityusing 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.KEYWORDS:power supply and distribution, power distribution reliability，reactive compensation, load distributionThe 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 electricknowledge, 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 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 modesabout 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 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 electricdistribution 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. 1996.6Relay protection development present situationInstitution:Tianjin Electric Power Association[Abstract]reviewed our country electrical power system relay protec tion technological development process,has outlined the microcomputer re lay protection technology achievement,proposed the future relay prote ction technological development tendency will be: Computerizes, networked, protects, the control, the survey, the data comm unication integration and the artificial intellectualization.[ Key word ] relay protection present situation developme nt，relay protections future development1 relay protection development present situationThe electrical power system rapid development to the relay protection proposed unceasingly the new request, the electr onic 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 prot ection discipline, the relay protection design, the relay man ufacture industry and the relay protection technical team gro ws 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 tech nology , completed to have the deep relay protection theory attainments and the rich movement experience relay protectio n technical team, and grew the instruction function to the national relay protection technical team's establishment. The acheng relay factory introduction has digested at that time the overseas advanced relay manufacture technology, has establ ished our country relay manufacturing industry. Thus our coun try has completed the relay protection research, the design, the manufacture, the movement and the teaching complete sys tem in the 60's. This is a time which the mechanical and electrical relay protection prospers, was our country relay p rotection technology development has laid the solid foundation .From the end of the 50's, the transistor relay protectio n was starting to study. In the 60's to the 80's in arethe times which the transistor relay protection vigorous deve lopment and widely uses. Tianjin University and the Nanjing electric power automation plant cooperation research 500kv tra nsistor direction high frequency protection the transistor hig h frequency block system which develops with the Nanjing ele ctric power automation research institute is away from the p rotection, moves on the Gezhou Dam 500 kv line , finished the 500kv line protection to depend upon completely from the overseas import time.From the 70's, started based on the integration operation al amplifier integrated circuit protection to study. Has form ed the complete series to at the end of 80's integrated ci rcuit protection,substitutes for the transistor protection grad ually. The development, the production, the application the i ntegrated circuit protects which to the beginning of the 90' s still were in the dominant position, this was the integrated circuit protection ti me. The integrated electricity road work frequency conversion quantity direction develops which in this aspect Nanjing el ectric power automation research institute high frequency prot ected the vital role , the Tianjin University and the Nanji ng electric power automation plant cooperation development int egrated circuit phase voltage compensated the type direction high frequency protection also moves in multi- strip 220kv a nd on the 500kv line.Our country namely started the computer relay protection research from the end of the 70's , the institutions of hi gher learning and the scientific research courtyard instituteforerunner's function. Huazhong University of Science and Te chnology, southeast the university, the North China electric power institute, the Xian Jiaotong University, the Tianjin Un iversity, Shanghai Jiaotong University, the Chongqing Universit y and the Nanjing electric power automation research institut e one after another has all developed the different principl e, the different pattern microcomputer protective device. In 1984 the original North China electric power institute develo ped the transmission line microcomputer protective device firs t through the appraisal, and in the system the find applica tion, had opened in our country relay protection history the new page, protected the promotion for the microcomputer to pave the way. In the host equipment protection aspect, the generator which southeast the university and Huazhong Univer sity of Science and Technology develops loses magnetism prote ction, the generator protection and the generator?Bank of tra nsformers protection also one after another in 1989, in 1994 through appraisal, investment movement. The Nanjing electric power automation research institute develops microcomputer li ne protective device also in 1991 through appraisal. The Tia njin University and the Nanjing electric power automation pla nt cooperation development microcomputer phase voltage compensa ted the type direction high frequency protection, the Xian J iaotong University and the Xu Chang relay factory cooperation development positive sequence breakdown component direction h igh frequency protection also one after another in 1993, in 1996 through the appraisal. Heres, the different principle, the different type microcomputer line and the host equipmen t protect unique, provided one batch of new generation ofperformance for the electrical power system fine, the funct ion has been complete, the work reliable relay protection in stallment. Along with the microcomputer protective device rese arch, in microcomputer aspect and so on protection software, algorithm has also yielded the very many theories result. May say started our country relay protection technology from the 90's to enter the time which the microcomputer protect ed.2 relay protections future developmentThe relay protection technology future the tendency will be to computerizes, networked, the intellectualization, will p rotect, the control, the survey and the data communication i ntegration development. 2.1 computerizesAlong with the computer hardware swift and violent develo pment, the microcomputer protection hardware also unceasingly is developing. The original North China electric power instit ute develops the microcomputer line protection hardware has e xperienced 3 development phases: Ispublished from 8 lists cpu structure microcomputer prote ction, does not develop to 5 years time to the multi- cpu structure, latter developed to the main line does not leav e the module the big modular structure, the performance enha nces greatly, obtained the widespread application. Huazhong Un iversity 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 mic rocomputers protection.The Nanjing electric power automation research institute f rom the very beginning has developed 16 cpu is the foundati on microcomputer line protection, obtained the big area promo tion, at present also is studying 32 protections hardware sy stem. 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 c pu as the foundation microcomputer line protection, in 1988 namely started to study take 32 digital signals processor (d sp) as the foundation protection, the control, the survey in tegration microcomputer installment, at present cooperated with the Zhuhai Jin automatic equipment company develops one kin d of function complete 32 big modules, a module was a mini computer. Uses 32 microcomputers chips only to focus by no means on the precision, because of the precision the a/d sw itch 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 computat ion speed, very big addressing space, rich command system an d 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 integ rates the high speed buffer in cpu.The electrical power system the request which protects to the microcomputer enhances unceasingly, besides protection ba sic function, but also should have the large capacity breakdown information and the data long-term storage space, the fa st data processing function, the formidable traffic capacity, with other protections, the control device and dispatches t he networking by to share the entire system data, the infor mation and the network resources ability, the higher order l anguage programming and so on. This requests the microcompute r protective device to have is equal to a pc machine funct ion. In the computer protection development initial period, o nce conceived has made the relay protection installment with a minicomputer. At that time because the small machine vol ume big, the cost high, the reliability was bad, this tenta tive plan was not realistic. Now, with the microcomputer pro tective device size similar labor controlling machine function , the speed, the storage capacity greatly has surpassed the same year small machine, therefore, made the relay protecti on with complete set labor controlling machine the opportunit y already to be mature, this will be one of development di rections which the microcomputer protected. The Tianjin Univer sity has developed the relay protection installment which Che ng Yongtong microcomputer protective device structure quite sa me not less than one kind of labor controlling machine perf orms to change artificially becomes. This kind of equipment merit includes: has the 486pc machine complete function, ca n 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 cra ft excellent, quakeproof, guards against has been hot, guards against electronmagetic interference ability, may move in th e 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 wilfully regarding the different protection, the disposition nimble, is easy to expand.Relay protection installment , computerizes is the irrever sible development tendency. How but to satisfies the electric al 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 sp ecifically the thorough research. 2.2 networkedThe computer network has become the information age as t he information and the data communication tool the technical prop, caused the human production and the social life appe arance has had the radical change. It profoundly is affectin g 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 associat ion protection, all relay protections installment all only ca n respond the protection installment place electricity spirit. The relay protection function also only is restricted in t he excision breakdown part, reduces the accident to affect t he scope. This mainly is because lacks the powerful data co mmunication method. Overseas already had proposed the system protection concept, this in mainly referred to the safe auto matic device at that time. Because the relay protection func tion not only is restricted in the excision breakdown part and the limit accident affects the scope (this is most impo rtant task), but also must guarantee the entire system thesecurity 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 th e superposition brake gear in analyze these information and in the data foundation the synchronized action, guarantees th e system the security stable movement. Obviously, realizes th is kind of system protection basic condition is joins the e ntire 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 realizat ion protective device computer networking also has the very big advantage. The relay protection equipment can obtain syst em failure information more, then to the breakdown nature, t he breakdown position judgment and the breakdown distance exa mination 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 i nformation, only then realization protection computer networked , can achieve this point.Regarding certain protective device realization computer ne tworkings, also can enhance the protection the reliability. T he Tianjin University in 1993 proposed in view of the futur e Three Gorges hydroelectric power station 500kv ultrahigh vo ltage multi- return routes generatrix one kind of distributional generatrix protection principle, developed successfully thi s kind of equipment initially. Its principle is disperses th e traditional central generatrix protection certain (with to protect generatrix to return way to be same) the generatrix protection unit, the dispersible attire is located in on v arious return routes protection screen, each protection unit joins with the computer network, each protection unit only i nputs this return route the amperage, after transforms it the digital quantity, transmits through the comput er network for other all return routes protection unit, each protection unit acts according to this return route the am perage and other all return routes amperage which obtains fr om the computer network, carries on the generatrix differenti al 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 gener atrix isolation. When generatrix area breakdown, each protecti on 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 rel iability compared to the traditional central generatrix protec tion principle. Because if a protection unit receives the di sturbance 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 exc ises, this regarding looks like the Three Gorges power plant to have the ultrahigh voltage generatrix the system key po sition 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 pe rformance, the multi-purpose computer, is in an entire electr ical power system computer network intelligent terminal. It m ay gain the electrical power system movement and breakdown a ny information and the data from the net, also may protect the part which obtains it any information and the data tr ansfer 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, th e 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, li ke the transformer, the line and so on the secondary voltag e, the electric current all must use the control cable to direct to . Lays the massive control cable not only must m assively invest, moreover makes the secondary circuit to be extremely complex. But if the above protection, the control, the survey, the data communication integration computer inst allation, will install in outdoor transformer substation by t。

分数: ___________任课教师签字：___________ 华北电力大学本科生结课作业学年学期：2011-2012学年第二学期课程名称：专业外语阅读(自动化)学生姓名：学号：提交时间：2012年6月19 日The Major Component Assembly Line of anAircraftEvery Boeing commercial is airplane is customized for a specific customer. Manufacturing processes of some major component are desirable to follow the FMS concept in a customized manufacturing environment. In the case study that follows,a wing assembly process is examined by means of discrete simulation modeling. There are more than thirty complex processes applied to more than fifteen machine classes in this example .Most processes require a different number of labor entities from various labor classes.The overall pace of the whole system is desired to be a variable that impacts the process time of all related processes,as well as the number of assigned laborers.The modular approach to MCM system design not only benefits the overall performance of flexible MCMsystem,but also enhances simulation-modeling exercises.Discrete event simulation technology in this study employs the same platform concept as in modeling highly flexible and rapid reconfigurable production lines.such modeling methods reflect manufacturing processes according to the every-changing customized demands.Many fundamental manufacturing process parameters,such as layout reconfigurations, and resource re-allocations, can be derived ahead of time from the simulation models.A high-level process flow of this simulation model is shown below in Figure 5-4-1, where sourcel1 generates incoming parts according to the system takt time with optional statistical distributions. Buffer S receives incoming parts via the only crane resource in the system. The part will then be lifted by the crane to the machineB where multiple processes will be performed by multiple resources. The part then continues to move from the machine B to the machine P, the end of the process line. Multiple processes are assigned throughout this line on each machine. An additional process is needed in the middle of the line where the part will be transferred to the buffer A followed by a couple of external processes. Afterwards, buffer A receives the part and calls for the overhead crane to transfer the part back to buffer T where the part will continue through the rest of the process. At the end of the line, the part goes from the machine P to the buffer A then to the sink, which is the final destination of all parts in the simulation model.Two different part-carrying platforms are involved in the system. The “highspeed” dolly transfers parts to and from buffer A. The “low speed” dolly carries one part at a time from machine B all the way to machine P. additional components are introduced to the system from source 2 and 3 at different stages of this process line.Resource class types in this model consist of labor, machine , and Automatic Guided Vehicle (AGV) elements. The machine class stands alone for each machine, while the labor and AGV classes are managed by their respective controllers. Those thirty plus processes that are stand-alone objects can be assigned to multiple machines. Thus, each machine has from two to six assigned processes . Processes run at all times in an endless do-loop as part of the nature of logic and its assigned time duration on the machine where it resides. After the last process sequence of the last machine class has been executed, the part is transferred to the sink class where it will be logically destroyed and removed from the modeling system.A Shop Data File containing resource, layout, and process information of an assembly line is used to generate Batch Control Language (BCL) file, according to the process discussed in the next paragraph. This BCL file can then be directly executed in QUEST. The aircraft major component assembly line simulation is created and driven by this BCL file.Because this model is created from an XML-based Shop Data File, modifying scenarios of the model file can be easily accomplished by changing element attributes of the source XML file. As in the example shown above, the BCL specific commends, such as CREATE PART CLASS, are managed in the XML style sheet. Simulation model object related information, such as the part color and name of the part class “Part737RHwing” are originated from the Shop Data File. A complete new BCLis file generated per flexible manufacturing scenario. This BCL file then executes and generates a customized QUEST simulation model for its matching conceptual FMS environment.The approach of this simulation modeling successfully manages a flexible customized manufacturing system in a flexibly modulated and customized fashion. For each complicated customized scenario, it is comprehensive that traditional manual modeling modification will take much longer effort than this technique. As compared to alternative approaches to this MCM application, benefit of this innovative methodology is evident in the following points:●Customizable●Ease of deployment●Portability of the XML-base shop data file●Popularity of the XML language●Scalable●Reusable of the modulated seed model fileAdditional detailed verification between simulation models and flexible MCM exercises on the shop floor remain to be fully performed once this conceptual process development turns into reality. Nevertheless, approaches and methodologies presented in this work illustrate unparalleled advantages in operating flexible and customized manufacturing systems.complex optimization methods based for example on evolutionary algorithms have not been selected.Strategy A: First free lineThis is probably the simplest of all scheduling policies but unfortunately in many cases not a very efficient one. It has been considered in this work as a base for comparison with other, more advanced, strategies. First free line strategy will order the batches by increasing estimated start time. These batches will then be sent to the first production line becoming available. The choice of the production line doesn’t depend on any specific criterion. This is the worst-case scenario and therefore only poor results are expected.Strategy B: Priority to oven temperatureThis strategy is slightly more advanced than the first free line strategy: priority is given to the reduction of setup times for the production lines. Longest setup times appear to be for the soldering oven, where temperature changes may take up to an hour. It makes sense therefore to sort batches out according to their required soldering temperature.Strategy B categorizes batches according to their soldering temperature and in each category, those batches are ordered by increasing start time. Production lines are then affected to a specific oven temperature in order to minimize setups.Strategy C: Improved oven temperature priorityBased on the strategy B, this strategy keeps the characteristics described above. Main improvement is made on the simulation termination, where strategy B had the disadvantage to let some lines run empty much earlier than other ones, depending on the workload for a specific oven setting. With strategy C, when a production line runs empty, state of the workshop is observed. If another production line has an important remaining workload and several orders in its queue line, then part of this production will be rerouted to the empty production line. This way, oven setup is only done when no other batch is available for a given production line.Strategy D: Mixed strategyMixed strategy is a result of observations made on the previous strategy. Changing the oven temperature is a long process but doesn’t necessarily penalize production when done in an intelligent fashion. Production lines rarely run completely empty for a specific temperature setting, so strategy C would never apply in a real case. However it is not considered clever for example to run a production line whenonly few orders are scheduled at a much later date. For this reason it is possible to introduce time windows in which strategy C would apply.Mixed strategy starts production based on an oven temperature priority. However, when workload diminishes and a production line runs empty in a given time window, then orders will be rerouted from the production line with the heaviest workload. After completion, production can go back to normal.译文：飞机主要构件装配线波音公司的每一架商业飞机都是为特定的顾客定制的。