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.     

温差电致冷组件计算机辅助设计

在温差电组件设计过程中,可变参数较多,得到的组件结构有多种,靠人工计算分析工作量较大;同样,对应多级组件,计算量更大,容易出错,设计得到的最终结果可比性较差,得到最佳设计方案的几率较小。采用计算机辅助设计解决以上问题。用VisualBasic语言编写了设计程序,该程序有良好的输入界面,使用者清晰地了解操作过程,一步一步完成其设计。在设计过程中,该程序提供所有设计的可能性,设计人可随意改变设计参数,得到任意结果,通过比较得到最优设计结果。该程序能够进行从单级组件到二级组件的设计,设计输出为表格形式,设计结果可保存再用。     

江门市电网规划计算机辅助系统

介绍了江门市供电局计算机辅助电网规划系统,具体地阐述了该系统的总体结构及主要功能。该系统充分地利用现有配电网地理信息系统,实现电力资源的合理调配,并成为江门供电局电网规划的新型工作平台。     

配电网规划计算机辅助决策系统

给出了配电网优化决策的数学模型,并开发了图形化的配电网规划计算机辅助决策实验系统.配电所的初始位置通过负荷矩法确定后,采用自动寻优算法确定其最终位置坐标;采用prim算法来优化网架结构;利用经济电流密度法选择导线截面,并采用边际电压费用法加以校验.实验系统以AutoCAD为图形界面,结合数据库系统,实现了数据与图形的联动,方便数据输入和结果查看.     

Computer aided tools in gas circuit breaker design

A software tool that allows the numerical investigation of the gas flow in circuit breaker chambers has been devised. A zonal grid methodology, with a corresponding finite-volume flow solver for the Euler equations, has been implemented for the treatment of the intricate geometries of the interrupter. Computational examples to illustrate the validity of the method are presented. Experimental tests were done on full-size breakers, and the results are analyzed using the proposed computational approach     

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     

Computer models of complex multiloop branched pipeline systems

This paper describes the principal theoretical concepts of the method used for constructing computer models of complex multiloop branched pipeline networks, and this method is based on the theory of graphs and two Kirchhoff’s laws applied to electrical circuits. The models make it possible to calculate velocities, flow rates, and pressures of a fluid medium in any section of pipeline networks, when the latter are considered as single hydraulic systems. On the basis of multivariant calculations the reasons for existing problems can be identified, the least costly methods of their elimination can be proposed, and recommendations for planning the modernization of pipeline systems and construction of their new sections can be made. The results obtained can be applied to complex pipeline systems intended for various purposes (water pipelines, petroleum pipelines, etc.). The operability of the model has been verified on an example of designing a unified computer model of the heat network for centralized heat supply of the city of Samara.     

Computer aided coordination of directional relays: determination ofbreak points

The directional overcurrent and distance relays of a multiloop network must be set in a sequence to ensure coordination. The starting points of the sequence are called break points. An algorithm to determine the minimum number of break points is presented. It can be readily implemented on a computer and forms a basic component of a computer-aided-design package for a protective system     

Computer aided coordination of line protection schemes: IEEEcommittee report

The IEEE PSRC Working Group on Computer Aided Coordination of Line Protection Schemes was established in 1985 to investigate the application of computers to the task of setting and verifying the setting of line protective devices. This report provides the findings of the Working Group regarding the functional requirements of the database, software, and hardware for this system as well as the methods of presenting the results to the protection engineer     

计算机辅助继电保护整定计算中的图论方法

系统地阐述了华东电力调度局和清华大学电机系联合开发的《继电保护整定计算综合程序》中所采用的图论算法。它主要包括：（１）ｌｉｎｋｎｅｔ数据结构的存储;（２）深度优先搜索／回溯法（ＤＦＳ／ＢＴ法）获得简单回路矩阵;（３）求取继电保护整定计算所需的一个极小断点集;（４）多回线的处理。最后给出一个实际的算例。     

Ion dynamics near charged electrodes with excluded volume effect

The goal of this paper is to analyze ion relaxation around a charged electrode taking into account finite ion volume and frequency. Time-dependent and electrostatic equations for ion behaviour near an electrode are developed and include the effects of nonequilibrium and steric hindrance. Time-dependent wave equations for the potentials are developed in the Lorentz gauge. The charge density is expressed as a sum of the quasi-steady state solution plus a nonequilibrium term. For slowly changing potentials the ions are in quasi-equilibrium and we show that in this limit the potential satisfies the sinh-Gordon equation. New solutions to this nonlinear time-dependent equation are developed. In the low voltage limit the equation reduces to the Klein-Gordon equation, time-dependent analog of the Debye-Huckel equation. We also present equations for capacitance and surface charge     

基于管道流量泄漏的计算机模糊调度设计

针对管道流量泄漏和管网突发性的爆管,以管道流量泄漏为应用对象,将模糊调度设计应用于管道流量泄漏监测中,研究具有模糊截止期的多控制任务的实时调度问题,提出奉献度的概念和最大奉献优先(U)F)的调度策略.通过仿真比较LDF和TLDF两种调度策略,实现具有模糊截止期的控制任务调度,能够减少并均衡控制性能损失,同时提高系统计算资源的使用率.     

Computer aided instruction of power transformer design in theundergraduate power engineering class

This paper describes a single-phase transformer design suitable for classroom use. The scope of this design is limited to the specification for the core and coils of the transformer. Both shell and core configured transformers are designed in this paper. A computer program is developed for the purpose of illustrating the design procedure and demonstrating how it works. The objective is to meet all performance requirements at minimum cost     

基于图像处理的多孔电极孔隙率的计算

针对固体氧化物燃料电池(SOFC)的电极孔隙率评估问题,提出了一种基于区域生长的图像分割改进方法来标识出电子显微镜下电极图像中的孔隙。该方法首先利用Otsu阈值法获取原图像的二值图像并标记连通区域,然后在每一个连通区域选取一个灰度值最小的像素点作为种子点进行区域生长,最后根据区域生长后的结果图像计算SOFC孔隙率。实验结果表明该方法可以有效地计算SOFC电极孔隙率用于分析SOFC的性能。     

Computer aided modelling of an interdigitated microelectrode array impedance biosensor for the detection of bacteria

Electrostatic finite element modelling software and an ac equivalent circuit model have been used to investigate an impediometric microelectrode array biosensor for the detection of bacteria. The electrostatic model showed the capacitance of the biosensor to decrease with increasing numbers of bacteria trapped on the sensor?s surface in a suspension of relatively high dielectric permittivity. Optimization of the model suggests that reducing the spatial wavelength of the biosensor?s electrodes either through a decrease in electrode width or gap will improve the sensor?s sensitivity. In addition, the model confirmed that the permittivity of the external medium had a significant effect on detection efficiency. Increased sensitivity in suspensions of lower relative dielectric permittivity was observed. The equivalent circuit model (ECM) was used to analyze the effect of high levels of immobilized bacteria at fixed signal frequencies (100 Hz and 1 MHz). It has been shown that the ECM discussed in this paper is able to successfully model the experimental data for the actual sensor in the low frequency ranges, allowing prediction of the sensor response and analysis of its performance. Overall, the modelling results obtained in the present paper are in general agreement with those from other published data and can be used in the development and optimization of impediometric biosensors for rapid and reliable detection of pathogenic bacteria.     

Insulation recovery characteristics after current interruption by various vacuum interrupter electrodes

Insulation recovery characteristics after current interruption for a vacuum interrupter were investigated. We used spiral and axial magnetic field electrodes for comparison of the electrode structure, while CuBi and CuCr were also used for comparison of the contact material. This paper describes how the axial magnetic field electrode and CuCr (50%) performed best in our experimental data. In addition, we discussed reasons for the variation in characteristics between electrodes.     

自动化三维超声图像无探头耦合区域的计算机辅助排除算法

自动化三维超声成像时,只有在探头和皮肤间存在良好耦合接触的区域才能形成有效超声信号.通过构建一个二维冠状面图像掩模实现了对非耦合区域图像的计算机辅助排除.算法首先通过分别对多帧连续和间断的二维冠状面图像相同位置的像素点做均值处理,得到冠状面均值图像;然后分别将对连续和间断冠状面做均值处理后的图像使用双峰阈值分割法进行阈值处理,得到二值图像,再使用形态学图像处理方法对二值图像进行处理,在处理后的两张二值图像中选择最优二值图像作为掩模图像;最后使用掩模图像对待处理冠状面图像的非耦合区域进行排除并使用伪彩色显示冠状面耦合区域.结果表明,本算法可实现对自动化三维乳腺超声(ABUS)数据无探头耦合区域的自动排除,能有效避免后续图像处理过程对非耦合区域的无效运算.     

Investigation of ramped air arcs near current zero in dual-flownozzle system

Ramped air arcs with a dI/dt= 6 A/μs were investigated in dual-flow nozzle system. The nozzle pressure ratio was varied to study the arc under different flow Mach number gradients. The dI/dt, dV/dt, and postzero resistance and current measurements were taken for an electrode separation of 5.5 cm and a nozzle gap spacing of 1.23 cm. The adverse shock wave effects were quantitatively observed for nozzle pressure ratios with separated flow in the nozzle. The arc power, which is equal to the total radiation losses and heat transferred from the plasma, was determined near current zero for subsonic and supersonic flow fields. It was shown that the nozzle pressure ratio is a very important parameter in the circuit breaker performance. A comparison of this work with Brown Boveri data was made. It was concluded that the convection stabilized ramped arcs near current zero are laminar and become unstable in the dielectric regime     

线路零序电流保护计算机整定中运行方式的选择

合理快速地选择运行方式是继电保护整定当中非常重要的环节,传统的选择方法只考虑极少的运行方式使得定值存在一定的不合理性.文中提出了一种有效的判据,大大缩小了参与方式组合的元件范围,使方式组合更加快速和准确.同时,文章还介绍了基于该思路的计算机进行零序电流保护运行方式组合的一般步骤.     

线路零序电流保护计算机整定中运行方式的选择

合理快速地选择运行方式是继电保护整定当中非常重要的环节 ,传统的选择方法只考虑极少的运行方式使得定值存在一定的不合理性。文中提出了一种有效的判据 ,大大缩小了参与方式组合的元件范围 ,使方式组合更加快速和准确。同时 ,文章还介绍了基于该思路的计算机进行零序电流保护运行方式组合的一般步骤