Computer-aided design of porcelain insulators under pollutedconditions

The development of a user-friendly, interactive personal computer package for designing insulators to be used in polluted conditions is presented. This is accomplished by integrating a dynamic arc model that computes the pollution flashover voltage within the Microsoft Windows application program. Suspension, station post and pin type insulators of numerous shapes have been incorporated into the package. The model is capable of handling AC and DC voltages, in addition to uniform and nonuniform pollution distributions on the insulator surface. The use of the model as a design tool to predict the insulation requirement for a given system voltage, and as a maintenance tool to determine the critical contamination level (in terms of ESDD) that will cause flashover of the insulator at the operating voltage, has been demonstrated. Wherever possible, comparisons of the model predictions with experimental data have been made, and good agreement has been obtained     

Computer aided power transmission planning

The Interactive Power Transmission Planning (IPTP) package developed at the Kuwait Institute for Scientific Research comprises a security assessment program so the network planning engineer can test the technical feasibility of a given network and a sensitivity analysis program that indicates to the planner the best line to reinforce. These basic computational planning facilities are presented to the engineer through special software using interactive computing and computer graphics. The package is devised so that it can be used by engineers with limited computer programming and numerical analysis skills.     

INTEGRATED SOFTWARE FOR OPTIMAL DIRECTIONAL OVERCURRENT RELAY COORDINATION

ABSTRACT

This paper reports the development of fully integrated software for the optimal directional overcurrent relay coordination of interconnected power systems. Different software packages like load flow analysis, fault analysis, determination of backup/primary relay pairs, main relay coordination program, etc. have been integrated. The program could be run as an interactive package or as an off-line package, depending upon the choice of the user. The information needed for the coordination is stored and used by the software. No data base management packages are needed to manage huge data generated by the program. The software uses an efficient method to generate, store and retrieve the data as per the requirements of the coordination. In the Interactive mode, the information about the coordination time interval, range of the relay settings, limits to the maximum and minimum time of operation of the relays, etc., are supplied. All other relevant data needed for coordination are generated by the software package itself. The usage of the program is illustrated by a case study involving the SPC 26-bus power system.     

电机电磁场的有限公式计算技术

有限公式方法是一种新型的基于全局变量的电磁场数值计算方法,该文针对工程中电机几何结构复杂的特点,研究了运用有限公式法计算电机内电磁场时的若干技术问题。提出了一个新的当网格单元形状为不规则三角形时的计算格式,避免了对大型矩阵的求逆运算。首次将全局变量中的源变量定义在原剖分网格上,将全局变量中的形态变量定义在映射剖分网格上,提高了在区域边界不规则的情况下多介质区域中磁场计算精度,和编程效率。该文还首次系统地介绍了有限公式方法中边界条件的处理方法,丰富完善了有限公式方法的理论体系。通过对一台实际电机的电磁场分步以及电气参数计算,并与有限元等方法的计算结果进行对比,验证了方法的可行性与正确性。     

电力系统中长期负荷预测 软件包的实现

开发了基于Ｗｉｎｄｏｗｓ９５下的中、长期电力负荷预测软件包。该软件包由负荷预测数据查询模块、预测方法模块、结果查询模块和图表输出模块四部分组成。该软件包具有人机界面友好,分析、计算快速,预测方法多样,适用范围广泛,目前已成功地应用于实际城网电力负荷预测中。     

Interactive computer program for planning the expansion of meshed transmission networks

A scheme is described for the interactive development of expansion strategies for transmission networks in which stability and voltage considerations are not of prime importance. According to the planning methodology adopted, the transmission/generation system is to be reinforced when it can no longer feed the peak demand without equipment overload in a single contigency. Outages of generators are considered, as well as the outages of transmission lines and transformers. Generation can be redispatched in order to eliminate overloads. If this is not possible, the model minimizes the load curtailment and identifies the weak parts of the system. It also ranks the possible investments according to their effectiveness in reducing the load curtailment. The planning engineer can build, interactively, several expansion policies by successive investment decisions. The model computes the discounted costs of the various policies developed. The files containing the expansion policies created are also automatically managed by the interactive package.The scheme has been implemented in a package called Tranex which consists of two separate interactive computer programs. An example illustrating the application of the method via this package to the Yugoslav network is given, along with computer performance details and an overview of the program structure.     

PSVSR:一种实用的静态电压安全性评估工具

介绍了一种基于“安全域”理论的静态电压安全性评估软件包——PSVSR的设计思想和实现方法。PSVSR具有友好的可视化交互界面,能够向电力运行人员提供正常及故障运行方式下有关电压稳定及支路热稳定极限的更为全面和系统的信息。PSVSR基于Windows操作系统,由Visual C 开发实现。PSVSR采用三层结构:用户界面层、核心计算层和后台支持层。这种三层结构使得PSVSR更加可靠、稳定、并易于扩展。最后基于EPRI 2000母线系统对PSVSR的特点及运行特性进行了说明。     

ADSS光缆与高压输电线路同杆并架全程三维电场分析与光缆挂点优化设计软件

详细给出了沿高压输电线路加挂ADSS光缆时电场的空间三维计算原理。为了优化计算，提出了线电荷与点电荷相结合的等效电荷法。在此基础上编制了分析输电线路任意截面及沿ADSS光缆走向的电位、场强分布的三维计算软件。此外，该程序还能考虑转角、换位、舞动等工况。对不同塔型的计算结果表明：软件中采用的算法合理，所得结果对ADSS的挂点选择和优化具有参考价值。     

基于GPS授时同步采样的在线网损计算

为了快速、准确、灵活地计算电网的功率损耗和能量损耗,开发了在线网损计算软件包。通过接口程序,电网运行参数直接由历史数据库中读取,并利用快速Ｐ－Ｑ 分解状态估计法对这些生数据进行加工,继而计算出准确的电网损耗。对实现在线网损计算的软件包进行了说明,软件已成功地应用于安徽省２２０ ｋＶ 主网的网损计算中,实践表明计算结果精确可靠,可满足较高的工程精度要求,也可应用于其它电网。     

有限元一解析结合解法在无界轴对称静电场问题数值解中的应用

无界电磁场问题的有限元数值分析研究有着重要的理论意义和实用价值.本文采用有限元-解析结合解法实现了有限元法在无界轴对称静电场问题数值分析中的应用,并兼顾了计算精度和效率,形成了一种新型解法.以典型的静电场问题为例,说明了有限元-解析结合解法精度高、简单易行和方便直观,具有实用价值.同时,还保留了有限元法的固有优点.     

Computer aided instruction of rotating electric machines viaanimated graphics

A menu-driven interactive graphics software package has been developed for use as an instructional aid for the electric machines course in the electrical engineering curriculum. The main purpose of this tool is to give the students a clearer understanding of the basics of the operation of rotating electric machines. The animation program was developed for displaying live and rotating diagrams depicting different modes of operation of synchronous generators. Different parts are identified with different colors. The interaction of the magnetic poles on the stator and on the rotor, and the relative spatial positions and time variations of the magnetic and electric quantities are demonstrated through moving images. The software features are described     

基于分时电价和激励补贴机制的家庭能量双层优化模型

为了降低居民日负荷曲线峰谷差,提高居民参与电网需求响应的积极性之前,文章基于分时电价和激励机制,提出双层模型实现家庭能量的优化调度。该模型以需求侧响应为手段,以家庭能量优化为策略,实现供电端与用电端的互动,刻画出电价、激励机制与用户用电行为之间的交互关系。外层模型在分时电价的环境下,采用模糊C-均值聚类算法(fuzzy C-means algorithm, FCM)对用户用电情况进行分析,以日负荷曲线削峰填谷为目标,设计包含激励补贴和峰谷系数的电力套餐。内层模型基于电力套餐实现家用电器的智能管理,模拟实施套餐前后的居民日负荷曲线,实时调整用电计划,使用户日负荷曲线满足电力套餐中的峰谷系数。通过仿真验证双层优化模型有效降低了用户日负荷曲线的峰谷差,且设计的电力套餐在用户侧有一定的实用性,有利于用户更加积极地参与电网的优化调度,满足电网削峰填谷的要求。     

Numerical solutions and mapping of electrostatic fields using theApple MacIntosh computer

The popularity, user-friendliness, and accessibility of personal computers encourages their use as powerful computational tools for numerical and graphical aids in the visualization of concepts that may seem abstract to students. Methods are presented for using the Apple MacIntosh computer for the numerical solution and mapping of fields for electrostatics, steady current flow, heat transfer, and source-free magnetostatics problems. The programs are totally menu-driven, consistent with the familiar MacIntosh interface, requiring minimal time on the part of the student to learn how to get into the program and obtain results, yet with enough power and versatility to enable students to do some fairly sophisticated computations if they wish. The program uses a finite-elements method and provides transient as well as steady-state solutions. This software is proving to be a valuable instructional aid in field mapping problems and the computation of capacitance and resistance in a first-level EM course     

Charges and forces on conductive particles in roll-typecorona-electrostatic separators

Mathematical modelling is a powerful tool in the optimization of electroseparation technologies and equipment. This paper proposes the use of a numerical method of field analysis to evaluate more accurately the charges and forces on millimeter-size conductive particles of virtually any shape in contact with an electrode. A program based on the boundary-element method was tested for this purpose, and provided the input data to an algorithm for the computation of particle trajectories. The results were in good agreement with the observations made on a laboratory electroseparator. The effect of space charge on the behavior of conductive particles was studied with a three-electrode system (a grounded grid, between a corona electrode and a metallic plate, energized by two high-voltage supplies of opposite polarities). The accuracy of numerical simulations of electroseparation processes is expected to increase when a mathematical model of particle motion in DC corona fields will be incorporated in the existing computer programs     

源网荷互动运行仿真平台的设计与研制

针对源网荷互动的未来电网发展趋势,分析了其运行仿真技术的需求,提出了仿真平台架构,阐述了功能模块部署及数据流程。进而,对互动运行仿真技术进行了详细阐述,提出了基于层次数据库的互动资源建模方法,建立了与调控系统的数据通信系统,阐述了平台实时仿真机制,并对动态潮流的频率计算模块进行了改进。同时,对参与精准切负荷和频率响应的大用户及温控负荷的仿真方法进行了阐述。搭建了一套源网荷互动运行仿真系统,并对其仿真效果进行了分析。     

Interactive display of vector fields inside waveguides

The educational software package WGVMAP has been developed to enable students to plot interactively the electric and magnetic field lines of TE and TM propagating modes in cylindrical waveguides. The waveguide cross-sections considered are rectangular, circular, sectoral, and circular with a conducting baffle. The vector field display and generation of the field lines can be performed on a very modest configuration of an IBM PC or compatible computer, and plotted on an x-y plotter. Examples are presented to demonstrate the interactive procedure for generating the field lines     

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     

Java-based graphical user interface for the MRUI quantitation package

This article describes the Java-based version of the magnetic resonance user interface (MRUI) quantitation package. This package allows MR spectroscopists to easily perform time-domain analysis of in vivo MR spectroscopy data. We show that the Java programming language is very well suited for developing highly interactive graphical software applications such as the MRUI software. We have also established that MR quantitation algorithms, programmed in other languages, can easily be embedded into the Java-based MRUI by using the Java native interface (JNI). This new graphical user interface (GUI) has been conceived for the processing of large data sets and uses prior knowledge data-bases to make interactive quantitation algorithms more userfriendly.     

A simple revolving-field demonstrator for the personal computer

A means is introduced for graphically demonstrating the concept of the revolving stator magnetic field of a polyphase machine. This is implemented on the personal computer by means of a simple Fortran algorithm. A graphics package allows dynamic display of the output. The locus of the revolving phasor may be made to travel at any convenient speed, and the demonstrator is capable of displaying the results of balanced or unbalanced stator currents of any phase sequence. A listing of the interactive Fortran algorithm developed by the author is included. Such a capability has been found useful for inclusion in personal computer-oriented machinery classroom or laboratory courses