Application independent interactive environment for power systemseducation

The authors present an interactive software package for the simulation of power system stability studies. The package is intended as a supplementary tool for the teaching of power system stability courses at the graduate level. The development of the package was done exclusively for IBM-PC and compatible computers. The hardware mainly requires VGA display and 640 kbyte of memory. Professional libraries used for the development of the package include Meta Windows, graphics Menu, and Object Professional. The authors describe the methods used for the integration of various analysis programs and the organization of the data and information pertinent to a system study     

Teaching nonlinear modeling, simulation, and control of electronic power converters using MATLAB/SIMULINK

This paper describes an efficient method to teach analysis and simulation of power electronic converters to undergraduate students, using system level nonlinear state-space models. System-level modeling of power electronic converters reproduces only the ideal switching behavior of the semiconductors and is a useful concept for the numerical simulation of power converters, since simulations present no convergence problems and require little computational time. Switched state-space models, programmed in the MATLAB/SIMULINK software package, can be advantageously used to simulate power converters at the system level and also to design and study their controllers. Switched state-space nonlinear models should be obtained using a theoretical framework suitable for the enhanced control of variable structure power systems. Since the method is inherently nonlinear, no approximated linear models are needed; and since state-space models are used, modern control techniques (sliding mode, neural networks, fuzzy logic) for power converters can easily be used. This paper summarizes the proposed methodology and gives some examples.     

基于拼图方式的电力电子电机系统通用仿真软件包

在综合分析,研究了国内外电力电子仿真软件的基础上,结合课题的实际应用背景和现有的工作条件,开发了基于拼图方式的电力电子电机系统通用仿真软件包。     

基于变参数追踪的暂态稳定分析与预防控制方法

采用了一种基于变参数追踪的电力系统暂态仿真算法.该算法将时间维作为微分代数-差分方程组的一个普通参数来处理,通过预估-校正的计算环节,连续求解得到系统在暂态过程中的轨迹.从该算法出发,提出了一类状态变量限值和约束函数对控制参数的灵敏度并推导了其公式.基于该灵敏度,提出了一种暂态稳定预防控制方法.该方法以控制总成本最小为目标,综合考虑多故障的协调.通过新英格兰10机39节点系统的算例,验证了文中方法的有效性.     

Power system stabilizers as undergraduate control design projects

The use of power system stabilizers (PSS) to damp power system swing mode oscillations is of practical importance. The design of PSS is taught in graduate level courses on power system dynamics and control, and has been the topic of numerous M.S. and Ph.D. theses. This paper discusses the experience in assigning PSS projects in an undergraduate control design course to provide students with a challenging design problem using three different techniques and to expose them to power system engineering. The details of the PSS design projects using root-locus, frequency-domain, and state-space methods are provided.     

A PC based software package for the equal area criterion of powersystem transient stability

This paper presents features and applications of an interactive graphical PC (DOS based) software package for the comprehension of transient stability using the equal area criterion method. The software is specifically useful for senior level undergraduate and first year graduate students in power system analysis courses. Utility engineers working with large-scale power systems can learn some basic concepts of transient stability by simulating the single machine infinite bus power system. A distinctive feature of this package is the user-friendly method for problem definition. Problems are defined by selecting options from menus without typical editor-like entry approach, used in other mathematical software, which normally have their own strict syntax     

Computer assisted learning in power system relaying

A computer package developed for power system protection design is used to teach protection coordination at City University, London. Examples of package use and experience gained from computer assisted learning in this subject are described. The simulation of protection systems gives students an opportunity to observe the actions of each device after they complete their protection schemes. In order to preserve flexibility within this self-learning environment, an expert system is included in the package. The use of an expert system is to make learning as effective as possible by providing guidance on the teaching material. It plays its role only if it is invoked. In other words, the expert system does not supervise learning, but can provide the necessary guidance if a request is made. If there is any error, the result of the simulation will also show the nature of the problem. The debugging function can help the students to detect the errors they have made and know how the devices work in the power system. The potential of a well-designed computer package is not only to strengthen teaching and learning, but also lead to creative contributions to the educational process. This benefit is not available through traditional lectures and textbooks     

Computer-aided design and analysis of linear multivariable controlsystems using the systematic design approach

A new approach for the design of multivariable feedback control systems in the frequency domain is presented. The techniques handle stability, performance, and robustness aspects of the design problem satisfactorily. The overall approach is systematic and intuitively appealing. A new computer-aided control system design package called SFPACK is developed. This package has implemented the new frequency response design techniques. The package is interactive and command-driven, and it is used as a teaching tool for helping the students to understand the concepts of the design approach. The MAT-LAB-derived control environment in SFPACK is extended to provide the user with an expert system development environment     

基于 Matlab/Simulink 的电力系统仿真工具箱的开发

详细介绍了电力系统暂态仿真软件的开发原理,并在此基础上开发了一个基于 Matlab/Simulink 的电力系统仿真工具箱(power system simulation toolbox,PSST).该仿真工具箱目前可完成潮流计算,小干扰稳定分析和动态时域仿真等方面的分析和研究,具有使用方便、可扩展性强等优点,克服了常规的大型商业化软件难以添加新模块的缺点,能够无缝地以 Simulink 模块的形式添加自定义新模块.此外,还可以根据实际仿真精度的要求灵活选用合适的 Simulink求解器进行仿真求解而无需修改仿真模型.通过对同一个新英格兰系统进行时域仿真,将 PSST 和电力系统工具箱(power system toolbox,PST)的仿真结果进行了分析对比,验证 PSST 仿真结果的有效性和准确性.最后以静止无功补偿器的广域附加阻尼控制器的设计为例阐述了用PSST设计控制器的基本原理和方法.可以看出,PSST 非常适合用于电力系统控制方面的研究     

A transient stability simulation package (TSSP) for teaching andresearch purposes

This paper describes a simulation package for performing transient stability study of a power system. The package includes four parts which are a fast decoupled load flow program, a short circuit calculation program, a transient simulation program and a plotting program. The simulation program consists of a coordinator and many modules, each of which simulates a power component, a controller or a physical process. Simulated results can be displayed on the screen by identifying the components and variables. The package is rich in providing modules for nonlinear representations of power components, though user-defined modules can also be easily interfaced into the package. The three data files are designed in such a way that maximum convenience in data preparation is achieved. The package can be used for teaching and doing research related to power system dynamics and control. Application examples and experience gained with the use of the package are discussed     

A distribution automation laboratory for undergraduate and graduateeducation

This paper outlines a five-year work of developing a distribution automation laboratory for undergraduate and graduate education at the Electrical Engineering Department of National Taiwan University. A scaled-down three phase distribution system model with a data acquisition system connected to a personal computer is built to facilitate physical experiments and real-time measurements. Remote control of the switches in the distribution system is made possible through the function of 8255 output ports and solid-state relays. Digital simulation programs are also written in order for the students to understand the basic concepts before they actually perform experiments. Three important applications in distribution automation, fault location identification, feeder reconfiguration, and feeder reactive power/voltage control using capacitor switching, are described     

超导储能单元在并网型风力发电系统的应用

风力发电系统发展的趋势是将风力发电机组直接与高压电网相连（简称并网型风力发电系统）。但风速变化造成风力涡轮机械功率变化,会使发电机输出的有功和无功产生波动,从而使电网的电能质量下降。该文提出使用超导储能SMES（super conducting magnetic energy storage system）单元使风力发电机组输出的电压和频率稳定。文中详细介绍了SEMS的调节原理及其最优控制方法,建立了SEMS模型和加入SMES后系统的线性化仿真模型,采用基因算法求最优反馈矩阵,并借助MATLAB软件包设计控制器,仿真结果表明SMES单元对并网型风力发电系统中风力发电机的输出稳定具有极大的改善作用。     

对称双芯移相器的接入对距离保护的影响及改进措施研究

对称双芯移相变压器(Phase Shifting Transformer, PST)作为潮流调控设备,能实现输电线路传输功率的调节。然而,PST接入线路后将改变线路阻抗分布、电压和电流信号,可能导致距离保护的误动或拒动。为了消除PST接入对常规距离保护造成的影响,根据PST对各序网故障分量的移相特性、PST序网等效阻抗以及接地、相间测量阻抗算法,推导出PST安装位置、PST移相角、故障位置均会对距离保护产生影响。基于距离保护受PST接入的影响机理,利用对称分量反变换、同步相量测量技术,提出了基于相角补偿和相量测量单元(Phasor Measurement Units, PMUs)的自适应距离保护。在此基础上,利用Matlab/Simulink搭建了PST的模型,并通过仿真验证了PST接入对距离保护影响机理推导的正确性以及所提出的自适应距离保护改进措施的有效性,为未来PST的深入研究和工程应用提供了理论支撑。     

An Open Source Power System Virtual Laboratory: The PSAT Case and Experience

This paper describes the authors' experience in the assessment of laboratory activities based on an open source software package for power system analysis, namely, Power System Analysis Toolbox (PSAT). PSAT is currently used in several universities for both undergraduate and graduate courses. PSAT has also its own Web forum, which provides support to students and researchers all around the world, thus resulting in an almost unique example of ldquovirtual laboratoryrdquo over the Internet. This paper attempts to answer through a variety of real-life examples the following open questions: What are the practical and pedagogical advantages of using an open source software with respect to proprietary software for power system analysis? What happens if a power system virtual laboratory is freely available on the Web? What is the difference between a class-based and a Web-based virtual laboratory?     

Application of linearized power system model to selection of PST controller input signal

This paper presents a selection method for phase shift transformer PST controller input signal. Simple conditions of input signal selection are obtained using frequency response analysis. The proposed method requires a suitable modeling of power system including PST device. The two types of power system models described in this paper are the nonlinear equations system model and the linearized model. The linearized model is represented as a block diagram transfer function model and as a state space representation model. The block diagram model presented in this paper has been used for the PST feedback input signal selection. Five locally available measurements at the switching node of the PST are considered. The results of frequency domain tests have confirmed that the block diagram transfer function model is a useful tool for power system analysis. The LQR method is used to achieve the final verification and the choice of input control signal.     

CACHE: An Interactive Control System Analysis and Design Package

CACHE is an interactive control engineering educational software package implemented on a personal computer workstation. The objective of this paper is to highlight the features of CACHE. CACHE provides undergraduate and graduate control engineering students with a comprehensive set of computational and graphics tools incorporating both classical and modern control engineering methodologies. The paper describes the menu-driven hierarchical command structure and the functions of the three CACHE subsystems: database manager, calculator, and plotter. The database manager maintains both state-space and frequency-domain transfer function models of linear time-invariant physical systems. CACHE includes analysis and design tools for both continuous-time and discrete-time systems. The application of CACHE is illustrated through the design of a position servomechanism.     

A project-oriented power engineering laboratory

This paper presents a power engineering educational laboratory suitable for undergraduate and graduate students. The laboratory development is based on the new academic system, called “Institut Universitaire Professionnalise (IUP)”, initiated in France. The pedagogical approach taken is one where the students revisit previously studied material placed in a practical context. This approach supports the prerequisite lecture material and allows study of some practical issues which are best handled in a laboratory setting. The experimental format gradually puts the students in touch with industrial realities. The laboratory experience culminates in a project, based on a computer aided design (CAD) technique, where the student analyzes, designs, simulates and demonstrates electric machines and power systems related topics     

`EDCON': an educational control system analysis and design program

A PC-based software package called EDCON which is a useful tool for teaching basic control system theory is discussed. It provides a user friendly environment that allows students to vary system parameters and design requirements to see the effects on system response. The package is designed around the root locus plot of a unity feedback control system. It uses a second order approximation technique to calculate and graph the unit step response of the system for any value of gain, and gives all the time and frequency parameters of the system. The package was developed to be used as a complement to an undergraduate course in control systems analysis and design