完整版电气工程毕业设计外文资料翻译.docx

1、完整版电气工程毕业设计外文资料翻译附录：外文资料翻译外文资料原文：A Virtual Environment for Protective Relaying Evaluation and TestingA. P. Sakis Meliopoulos and George J. CokkinidesAbstractProtective relaying is a fundamental discipline of power system engineering. At Georgia Tech, we offer three courses that cover protective rela

2、ying: an undergraduate course that devotes one-third of the semester on relaying, a graduate courseentitled “Power System Protection,” and a three-and-a- the concepts,theory, and technology associated with protective relaying, we a virtual environment. The virtual environment includes a) a power sys

3、tem simulator, b) a simulator of instrumentation for protective relaying with visualization and animation modules, c) specific protective relay models with visualization and animation modules, and d) interfaces to be performed. We refer to this set of software as the “virtual power system.” The virt

4、ual power system permits the in-depth coverage of the protective relaying concepts in minimum time and maximizes student understanding. The tool is not used in a passive way. Indeed, the students actively participate with well-designed projects such as a) design and implementation of multifunctional

5、 relays, b) relay testing for specific disturbances, etc. The paper describes the virtual power system organization and “engines,” such as solver, visualization, and animation of protective relays, etc. It also discusses the utilization of this tool in the courses via specific application examples a

6、nd student assignments.Index TermsAlgebraic companion form, animation, relaying,time-domain simulation, visualization.I. INTRODUCTIONRELAYING the security and reliability of electric power systems. As the technology advances, relaying of the system. It is indisputable that relaying the safety of sys

7、tems and protection of equipment. Yet, because of the complexity of the system and multiplicity of competing factors, relaying is a challenging discipline. Despite all of the advances in the field, unintended relay operations (misoperations) do occur. Many events of outages and blackouts can be attr

8、ibuted to inappropriate relaying settings, unanticipated system conditions, and inappropriate selection of instrument transformers. Design of relaying schemes strives to anticipate all possible conditions for the purpose of avoiding undesirable operations. Practicing relay engineers utilize a two-st

9、ep procedure to minimize the possibility of such events. First, in the design phase, comprehensive analyses are utilized to determine the best relaying schemes and settings. Second, if such an event occurs, an exhaustive post-mortem analysis is performed to reveal the root cause of the event and wha

10、t “was missed” in the design phase. The post-mortem analysis of these events is facilitated with the existing technology of disturbance recordings (via fault disturbance recorders or embedded in numerical relays). This process results in accumulation of experience that passes from one generation of

11、engineers to the next. An important challenge for educators is the training of students to become effective protective relaying engineers. Students must be provided with an understanding of relaying technology that encompasses the multiplicity of the relaying functions, communications, protocols, an

12、d automation. In addition, a deep understanding of power system operation and behavior during disturbances is necessary for correct relaying applications. In todays crowded curricula, the challenge is to achieve this training within a very short period of time, for example, one semester. This paper

13、presents an approach to meet this challenge. Specifically, we propose the concept of the virtual power system for the purpose of teaching students the complex topic of protective relaying within a short period of time. The virtual power system approach is possible because of two factors: a) recent d

14、evelopments in software engineering and visualization of power system dynamic responses, and b) the new generation of power system digital-object-oriented relays. Specifically, it is possible to integrate simulation of the power system, visualization, and animation of relay response and relay testin

15、g within a virtual environment. This approach permits students to study complex operation of power systems and simultaneously observe relay response with precision and in a short time.The paper is organized as follows: First, a brief description of the virtual power system is provided. Next, the mat

16、hematical models to enable the features of the virtual power system are presented together with the modeling approach for relays and relay instrumentation. Finally, few samples of applications of this tool for educational purposes are presented.II. VIRTUAL POWER SYSTEMThe virtual power system integr

17、ates a number of application software in a multitasking environment via a unified graphical user interface. The application software includes a) a dynamic power system simulator, b) relay objects, c) relay instrumentation objects, and d) animation and visualization objects. The virtual power system

18、simulation of the system under study;2) ability to modify (or fault) the system under study during the simulation, and immediately observe the effects of thechanges;3) advanced output data visualization options such as animated 2-D or 3-D displays that illustrate the operation of any device in the s

19、ystem under study.The above properties are fundamental for a virtual environment intended for the study of protective relaying. The first property guarantees the uninterrupted operation of the system under study in the same way as in a physical laboratory: once a system assembled, it will continue t

20、o operate. The second property guarantees the ability to connect and disconnect devices into the system without interrupting the simulation of the system or to apply disturbances such as a fault. This property duplicates the capability of physical laboratories where one can connect a component to th

21、e physical system and observe the reaction immediately (e.g., connecting a new relay to the system and observing the operation of the protective relaying logic, applying a disturbance and observing the transients as well as the relay logic transients, etc.). The third property duplicates the ability

22、 to observe the simulated system operation, in a similar way as in a physical laboratory. Unlike the physical laboratory where one cannot observe the internal operation of a relay, motor, etc., the virtual power system and animation of the internal “workings” of a relay, motor, etc. This capability

23、to animate and visualize the internal “workings” of a relay, an instrumentation channel, or any other device is based on the MS Windows multidocument-viewarchitecture. Each document object constructs a single solver object, which computations. The simulated system is represented by a set of objectso

24、ne for each system device (i.e. generators, motors, transmission lines, relays, etc). The document object can generate any number of view window objects. Two basic view classes are available: a) schematic views and b) result visualization views. Schematic view objects allow the user to define the si

25、mulated system connectivity graphically, by manipulating a single line diagram using the mouse. Result visualization views allow the user to observe calculated results in a variety of ways. Several types of result visualization views are supported and will be discussed later.Fig. 1 illustrates the o

26、rganization of device objects, network solver, and view objects and their interactions. The network solver object is the basic engine that provides the time-domain solution of the device operating conditions. To maintain object orientation, each device is represented with a generalized mathematical

27、model of a specific structure, the algebraic companion form (ACF). The mathematics of the algebraic companion form are described in the next section. Implementationwise, the network solver is an independent background computational thread, allowing both schematic editor and visualization views to be

28、 active during the simulation. The network solver continuously updates the operating states of the devices and “feeds” all other applications, such as visualization views,etc. The network solver speed is user selected, thus allowing speeding-up or slowing-down the visualization and animation speed.

29、The multitasking environment permits system topology changes, device parameter changes, or connection of new devices (motors, faults) to the system during the simulation. In this way, the user can immediately observe the system response in the visualization views.The network solver interfaces with t

30、he device objects. This interface requires at minimum three virtual functions:Initialization: The solver calls this function once before the simulation starts. It initializes all device-dependent parameters and models needed during the simulation.Reinitialization: The solver calls this function any

31、time the user modifies any device parameter. Its function is similar to the initialization virtual function.Time step: The solver calls this function at every time step of the time-domain simulation. It transfers the solution from the previous time step to the device object and updates the algebraic

32、 companion form of the device for the next time step (see next section “network solver.”)In addition to the above functions, a device object the schematic editor graphical user interface. Specifically,the device diagram can be moved, resized, and copied using the mouse. Also, a function is included

33、in this set, which implements a device parameter editing dialog window which “pops-up” by double clicking on the device icon. Furthermore,the schematic module interface allows for device icons that reflect the device status. For example, a breaker schematic icon can be implemented to indicate the breaker status.Finally, each device class (or