電氣工程畢業(yè)設(shè)計外文資料翻譯--繼電保護的評估與測試的虛擬環(huán)境

1、<p>　　4700單詞，2.6萬英文字符,7600漢字</p><p>　　出處：Meliopoulos A, Cokkinides G. A Virtual Environment for Protective Relaying Evaluation and Testing[C]// Hawaii International Conference on System Sciences. IEEE C

2、omputer Society, 2001:104--111.</p><p><b>　　附錄：外文資料翻譯</b></p><p><b>　　外文資料原文：</b></p><p>　　A Virtual Environment for Protective Relaying Evaluation and Testi

3、ng</p><p>　　A. P. Sakis Meliopoulos and George J. Cokkinides</p><p>　　Abstract—Protective relaying is a fundamental discipline of power system engineering. At Georgia Tech, we offer three course

4、s that cover protective relaying: an undergraduate course that devotes one-third of the semester on relaying, a graduate courseentitled “Power System Protection,” and a three-and-a-half-day short course for practicing en

5、gineers. To maximize student understanding and training on the concepts,theory, and technology associated with protective relaying, we have developed a numb</p><p>　　Index Terms—Algebraic companion form, ani

6、mation, relaying,time-domain simulation, visualization.</p><p>　　I. INTRODUCTION</p><p>　　RELAYING has always played a very important role in the security and reliability of electric power syste

7、ms. As the technology advances, relaying has become more sophisticated with many different options for improved protection of the system. It is indisputable that relaying has made significant advances with dramatic benef

8、icial effects on the safety of systems and protection of equipment. Yet, because of the complexity of the system and multiplicity of competing factors, relaying is a challengin</p><p>　　Despite all of the ad

9、vances in the field, unintended relay operations (misoperations) do occur. Many events of outages and blackouts can be attributed to inappropriate relaying settings, unanticipated system conditions, and inappropriate sel

10、ection of instrument transformers. Design of relaying schemes strives to anticipate all possible conditions for the purpose of avoiding undesirable operations. Practicing relay engineers utilize a two-step procedure to m

11、inimize the possibility of such events.</p><p>　　An important challenge for educators is the training of students to become effective protective relaying engineers. Students must be provided with an understa

12、nding of relaying technology that encompasses the multiplicity of the relaying functions, communications, protocols, and automation. In addition, a deep understanding of power system operation and behavior during disturb

13、ances is necessary for correct relaying applications. In today’s crowded curricula, the challenge is to achieve this train</p><p>　　The virtual power system approach is possible because of two factors: a) re

14、cent developments in software engineering and visualization of power system dynamic responses, and b) the new generation of power system digital-object-oriented relays. Specifically, it is possible to integrate simulatio

15、n of the power system, visualization, and animation of relay response and relay testing within a virtual environment. This approach permits students to study complex operation of power systems and simultan</p><

16、;p>　　The paper is organized as follows: First, a brief description of the virtual power system is provided. Next, the mathematical models to enable the features of the virtual power system are presented together with

17、the modeling approach for relays and relay instrumentation. Finally, few samples of applications of this tool for educational purposes are presented.</p><p>　　II. VIRTUAL POWER SYSTEM</p><p>　　T

18、he virtual power system integrates a number of application software in a multitasking environment via a unified graphical user interface. The application software includes a) a dynamic power system simulator, b) relay ob

19、jects, c) relay instrumentation objects, and d) animation and visualization objects. The virtual power system has the following features:</p><p>　　1) continuous time-domain simulation of the system under stu

20、dy;</p><p>　　2) ability to modify (or fault) the system under study during the simulation, and immediately observe the effects of thechanges;</p><p>　　3) advanced output data visualization optio

21、ns such as animated 2-D or 3-D displays that illustrate the operation of any device in the system under study.</p><p>　　The above properties are fundamental for a virtual environment intended for the study o

22、f protective relaying. The first property guarantees the uninterrupted operation of the system under study in the same way as in a physical laboratory: once a system has been assembled, it will continue to operate. The s

23、econd property guarantees the ability to connect and disconnect devices into the system without interrupting the simulation of the system or to apply disturbances such as a fault. This property</p><p>　　The

24、virtual power system implementation is based on the MS Windows multidocument-viewarchitecture. Each document object constructs a single solver object, which handles the simulation computations. The simulated system is re

25、presented by a set of objects—one for each system device (i.e. generators, motors, transmission lines, relays, etc). The document object can generate any number of view window objects. Two basic view classes are availabl

26、e: a) schematic views and b) result visualization views.</p><p>　　Fig. 1 illustrates the organization of device objects, network solver, and view objects and their interactions. The network solver object is

27、the basic engine that provides the time-domain solution of the device operating conditions. To maintain object orientation, each device is represented with a generalized mathematical model of a specific structure, the al

28、gebraic companion form (ACF). The mathematics of the algebraic companion form are described in the next section. Implementationwise, the ne</p><p>　　The network solver speed is user selected, thus allowing s

29、peeding-up or slowing-down the visualization and animation speed. The multitasking environment permits system topology changes, device parameter changes, or connection of new devices (motors, faults) to the system during

30、 the simulation. In this way, the user can immediately observe the system response in the visualization views.</p><p>　　The network solver interfaces with the device objects. This interface requires at minim

31、um three virtual functions:</p><p>　　Initialization: The solver calls this function once before the simulation starts. It initializes all device-dependent parameters and models needed during the simulation.&

32、lt;/p><p>　　Reinitialization: The solver calls this function any time the user modifies any device parameter. Its function is similar to the initialization virtual function.</p><p>　　Time step: The

33、 solver calls this function at every time step of the time-domain simulation. It transfers the solution from the previous time step to the device object and updates the algebraic companion form of the device for the next

34、 time step (see next section “network solver.”)</p><p>　　In addition to the above functions, a device object has a set of virtual functions comprising the schematic module interface. These functions allow th

35、e user to manipulate the device within the schematic editor graphical user interface. Specifically,the device diagram can be moved, resized, and copied using the mouse. Also, a function is included in this set, which imp

36、lements a device parameter editing dialog window which “pops-up” by double clicking on the device icon. Furthermore,</p><p>　　the schematic module interface allows for device icons that reflect the device st

37、atus. For example, a breaker schematic icon can be implemented to indicate the breaker status.</p><p>　　Finally, each device class (or a group of device classes) may optionally include a visualization module

38、, consisting of a set of virtual functions that handle the visualization and animation output. The visualization module interface allows for both two-dimensional (2-D) and three-dimensional (3-D) graphics. Presently, 2-D

39、 output is implemented via the Windows graphical device interface (GDI) standard. The 3-D output is implemented using the open graphics library (OpenGL). Both 2-D and 3-D output</p><p>　　III. NETWORK SOLVER&

40、lt;/p><p>　　Any power system device is described with a set of algebraicdifferential-integral equations. These equations are obtained directlyfrom the physical construction of the device. It is alwayspossible t

41、o cast these equations in the following general formNote that this form includes two sets of equations, which arenamed external equations and internal equations, respectively.The terminal currents appear only in the exte

42、rnal equations.Similarly, the device states consist of two sets: external states[i</p><p>　　Note that (1) may contain linear and nonlinear terms. Equation(1) is quadratized (i.e., it is converted into a set

43、of quadraticequations by introducing a series of intermediate variables and expressing the nonlinear components in terms of a series of quadratic terms). The resulting equations are integrated using a suitable numerical

44、integration method. Assuming an integration time step h, the result of the integration is given with a second-order equation of the formwhere , are past history func</p><p>　　Equation (2) is referred to as t

45、he algebraic companion form (ACF) of the device model. Note that this form is a generalizationof the resistive companion form (RCF) that is used by the EMTP [3]. The difference is that the RCF is a linear model that repr

46、esents a linearized equivalent of the device while the ACF is quadratic and represents the detailed model of the device.The network solution is obtained by application of Kirchoff’s current law at each node of the system

47、 (connectivity constraints).</p><p>　　Note that (3) correspond one-to-one with the external system states while (4) correspond one-to-one with the internal system states. The vector of component k terminal v

48、oltages is</p><p>　　related to the nodal voltage vector by(5)Upon substitution of device (2), the set of (3) and (4) become a set of quadratic equations (6)where x(t) is the vector of all external and intern

49、al system states.These equations are solved using Newton’s method. Specifically,the solution is given by the following expression(7)where is the Jacobian matrix of (6) and are the values ofthe state variables at the prev

50、ious iteration. </p><p>　　IV. RELAY INSTRUMENTATION MODELING</p><p>　　Relays and, in general, IEDs use a system of instrument transformers to scale the power system voltages and currents into in

51、strumentation level voltages and currents. Standard instrumentation level voltages and currents are 67 V or 115 V and 5 A, respectively. These standards were established many years ago to accommodate the electromechanica

52、l relays. Today, the instrument transformers are still in use but because modern relays (and IEDs) operate at much lower voltages, it is necessary to apply </p><p>　　Any relaying course should include the st

53、udy of instrumentation channels. The virtual power system is used to study the instrumentation error by including an appropriate model of the entire instrumentation channel. It is important to model the saturation charac

54、teristics of CTs and PTs, resonant circuits of CCVTs, etc. (see [6]). In the virtual power system, models of instrumentation channel components have been developed. The resulting integrated model provides, with precision

55、, the instrumentati</p><p>　　V. PROTECTIVE RELAY MODELING</p><p>　　Today, all new relays are numerical relays. These types of relays can be easily modeled within the virtual power system. Consid

56、er, for example, a directional relay. The operation of this relay is based on the phase angle between the polarizing voltage and the current. Modeling of this relay then requires that the phase angle between the polarizi

57、ng voltage and the current be computed. For this purpose, as the power system simulation progresses, the relay model retrieves the instantaneous values o</p><p>　　It is important that students be also involv

58、ed in the design of numerical relays. A typical semester project is to define the functionality of a specific relay and a set of test cases. The student assignment is to develop the code that will mimic the operation of

59、the relay and demonstrate its correct operation for the test cases.</p><p>　　The new technology of the virtual power system offers another more practical way to model relays. The virtual power system uses ob

60、ject-oriented programming. As such, it is an open architecture and can accept dynamic link libraries of third parties. A natural extension of the work reported in this paper is to use this feature to interface with comme

61、rcially available digital “relays.” The word “relay” is in quotation marks to indicate that the relay is simply a digital program that takes inputs of</p><p>　　VI. APPLICATIONS</p><p>　　The desc

62、ribed virtual environment has been used in a variety of educational assignments. The possible uses are only limited by the imagination of the educator. In this section, we describe a small number of educational applicati

63、on examples.</p><p>　　Figs. 3 and 4 illustrate an exercise of studying instrumentation channel performance. Fig. 3 illustrates an example integrated model of a simple power system and the model of an instrum

64、entation channel (voltage). The instrumentation channel consists of a PT, a length of control cable, an attenuator, and an A/D converter (Fig. 3 illustrates the icons of these components and their interconnection). Fig.

65、4 illustrates two waveforms: the voltage of phase A of the power system when it is experiencing</p><p>　　Fig. 5 illustrates the basics of an example application of the virtual power system for visualization

66、and animation of a modified impedance relay. The example system consists of a generator, a transmission line, a step-down transformer, a passive electric load (constant impedance load), an induction motor, and a mechanic

67、al load of the motor (fan). A modified distance relay (mho relay) monitors the transmission line. The operation of this relay is based on the apparent impedance that the relay “s</p><p>　　The visualization o

68、bject of this relay displays what the relay “sees” during a disturbance in the system and superimposes this information on the relay settings. Typical examples are illustrated in Figs. 6 and 7. The relay monitors the thr

69、ee-phase voltages and currents at the point of its application. The animation model retrieves the information that the relay monitors from the simulator at each time step. Subsequently, it computes the phasors of the vol

70、tages and currents as well as the sequenc</p><p>　　Fig. 7 provides the recorded impedance trajectory for the combined event of an induction motor startup followed by a three-phase fault near the low-voltage

71、bus of the transformer. The impedance trajectory is superimposed on the trip characteristics of this relay. In this case, the impedance trajectory does visit the trip “region” of the relay. This example can be extended t

72、o more advanced topics. For example, the animated display may also include stability limits for the “swing” of the generator</p><p>　　Another important protective relaying example is the differential relay.

73、In this example, we present the animated operation of a differential relay scheme for a delta-wye connected transformer with tap changing under load. The example system is shown in Fig. 8. It consists of an equivalent so

74、urce, a transmission line, a 30-MVA delta-wye connected transformer, a distribution line, and an electric load. A transformer differential relay Fig. 7. Animation of a mho relay for a three phase fault on th</p>&

75、lt;p>　　depth and in very short time with the aid of animation and visualization methods.</p><p>　　The virtual power system has been also used for testing of physical relays. This application is quite simp

76、le. The virtual power system has the capability to export voltage and current waveforms of any event and for any user-selected time period in COMTRADE format. Then, the COMTRADE file is fed into commercial equipment that

77、 generates the actual voltages and currents and feeds them into the physical relays. The actual response of the relays is then observed. This application was performed on the</p><p>　　Recently, a major relay

78、 manufacturer (SEL) has donated equipment to Georgia Tech and we are in the process of setting up the laboratory for routine use of this function by students. There are numerous other applications of the proposed virtual

79、 power system. The pedagogical objective is to instill a deep understanding of protective relaying concepts and problems in the very short time of one semester. The effectiveness of the proposed approach increases as new

80、 examples are generated and stored in</p><p>　　lecture. For example, a simple system with mutually coupled lines can be prepared, with relays at the ends of all lines. Then with a fault in one line, the rela

81、ys of the healthy line can be visualized and animated. The students can observe that the relays of the healthy line “see” zero-sequence current induced by the fault on another line. And more important, the students can m

82、ake changes to the designs of the lines and observe the relative effect of design parameters on induced voltages and cur</p><p>　　VII. CONCLUSION</p><p>　　This paper has discussed and presented

83、the virtual power system and its application for visualization and animation of protective relaying. The virtual power system has proved to be a valuable tool in the instruction of protective relaying courses. It is also

84、 an excellent tool for assigning term projects on various aspects of protective relaying. One important feature of the tool is that the user can apply disturbances to the system while the system operates (i.e., faults, l

85、oad shedding, motor s</p><p>　　The paper has also discussed three generic protective relay exercises using the virtual power system: a) visualization and animation of instrumentation channel error, b) impeda

86、nce relay, and c) a transformer differential relay. From these examples, it is clear that virtual laboratories can be quite beneficial from the educational point of view as they can provide insight of the system under st

87、udy that are impossible in a physical laboratory. In addition, the virtual power system is valuable for </p><p>　　The effectiveness of this approach has been assessed informally with discussions with student

88、s and evaluation of the term projects. The response is positive and enthusiastic (for example, two of the term project reports were over 100 pages long and the content reflected an excellent understanding of protective r

89、elaying concepts and technology). We plan to conduct formal evaluation of the approach by the students.</p><p>　　The tool is continuously under development as additional relay functions and animation and vis

90、ualization objects of various protective relay functions are being developed. This task is open ended because of the plethora of existing power system relaying devices and possible ways to visualize and animate their fun

91、ctions. There is also a multiplicity of term projects that can be designed and assigned to students with the virtual power system as the basic tool. We also plan to make this tool availa</p><p>　　附錄1 外文資料譯文&

92、lt;/p><p>　　繼電保護的評估與測試的虛擬環(huán)境</p><p>　　P. Sakis Meliopoulos 和 George J. Cokkinides</p><p>　　摘要：繼電保護是力學(xué)系統(tǒng)共層的基礎(chǔ)原則，我們提供了三種繼電保護課程：一個是研究生課程，三分之一學(xué)期來學(xué)名為電網(wǎng)保護的繼電保護，還有短暫的三天半的職業(yè)工程師課程。為了使學(xué)生最大限度的理解和訓(xùn)

93、練他們有關(guān)繼電的概念，理論，技術(shù)，我們發(fā)明了一些教育工具，全部都存在于一個虛擬的環(huán)境中。這樣的虛擬環(huán)境包括一個模擬電網(wǎng)送電器、一個可視化的動畫模組的繼電保護的模擬器儀表、特定的可視化的動畫模組式的繼電氣保護的模型和用來測試實際的繼電氣設(shè)備可以運行的硬件接口。我們稱這種軟件為虛擬電網(wǎng)。虛擬電網(wǎng)讓學(xué)生在最短的時間內(nèi)最大限度的理解繼電保護的縱向概念的范圍。這種工具不是被動的使用的。真實情況是，學(xué)生積極地的參與設(shè)計好的項目，例如多功能幾點起的設(shè)

94、計和實施和特定干擾的繼電測試等。這篇論文描述了虛擬電網(wǎng)組織，例如解算器，繼電保護的可視化和動畫等，也討論了這種工具通過特定的應(yīng)用例子和學(xué)生作業(yè)的課程中的實用性。</p><p>　　關(guān)鍵詞： 代數(shù)的同伴形式，動畫，繼電保護，時域模擬，可視化</p><p><b>　　簡介</b></p><p>　　繼電保護在電力系統(tǒng)的安全性和可靠性中一直都

95、扮演了非常重要的角色。由于技術(shù)進步，繼電保護變得更加復(fù)雜， 有太多不同的改善了的系統(tǒng)保護可以選擇。 無可爭議的是繼電保護有非常顯著的進步。在系統(tǒng)安全性和設(shè)備的保護上有戲劇性的益處。然而，由于系統(tǒng)的復(fù)雜性和競爭因素的多樣性，繼電保護是一項富有挑戰(zhàn)性的學(xué)科。除了在此領(lǐng)域所有的進步外，非計劃中的繼電保護操作（誤操作）確實發(fā)生了。許多運行中斷和停電的事故都可以歸結(jié)于不恰當(dāng)?shù)睦^電保護設(shè)置，意料之外的系統(tǒng)狀況以及對儀器變壓器不合適的選擇繼電保護的設(shè)

96、計方案力爭考慮到所有可能的情況來避免誤操作。實用繼電保護工程師使用兩步程序來最小化這樣誤操作的可能性。</p><p>　　在設(shè)計階段，實用綜合分析來決定最好的繼電保護方案和設(shè)置。</p><p>　　如果這樣的事故發(fā)生了，使用詳盡的事后分析來揭露事故原因的根源和設(shè)計階段究竟是什么弄錯了。</p><p>　　現(xiàn)在的干擾記錄技術(shù)可以加強事后分析的效果。（通過錯誤的干

97、擾記錄或者嵌入在數(shù)字繼電器中的記錄）這個過程的結(jié)果是一代一代的工程師傳遞下去的經(jīng)驗的積累。對于訓(xùn)練者來說一項重要的挑戰(zhàn)是把學(xué)生訓(xùn)練成更有效地繼電保護工程師的訓(xùn)練。學(xué)生必須具備對繼電保護技術(shù)的理解，包括繼電保護功能的多重性，交流性，規(guī)范性和自動化。另外，在干擾中為了正確的繼電保護應(yīng)用必須對電網(wǎng)的操作和行為有深刻的理解。在如今繁多的課程安排下，富有挑戰(zhàn)性的是在一個非常短的時段內(nèi)達到這樣的訓(xùn)練目的，比如說一個學(xué)期。這篇論文呈現(xiàn)了一個完成這個挑