WXH—14x型微机微波保护装置的研究

本文介绍了国内首次成功研制的WXH—14x型微机微波数字式分相电流差动保护的工作原理、特点及用途。该保护系统借助光纤数字通信、数字微波通信技术,将被保护线路两侧电流采样数据及有关信息对传,并辅以两侧数据的计算机同步调整而实现。理论分析与动模试验、型式试验及现场试运行结果表明,保护装置原理先进,动作速度快,可靠性高,抗干扰能力强,结构合理,对微波系统误码率指标要求低。装置可以作为110kV及以上各级输电线路的主保护和后备保护,尤其适用于同杆并架双回线、短线路及因高频通道拥挤而难以采用高频保护的线路。     

纳米线阵列结构温差电材料热电性能测试技术

介绍了一种新的一维纳米线阵列结构温差电材料热电性能测试技术。该技术创造性地采用了液流加热以及异地测温的新方法,成功地解决了对微米厚度的一维纳米线阵列结构热电材料试样两侧均匀加热并保持两侧的温差恒定,以及微米厚度的试样两侧测温的难题。依据这一原理建立了一维纳米线阵列结构热电材料性能测试系统。实验表明,该系统性能稳定,精度高,可胜任一维纳米线阵列结构热电材料的性能测试。     

WXH—14_x型微机微波保护装置的研究

本文介绍了国内首次成功研制的WXH—14x型微机微波数字式分相电流差动保护的工作原理、特点及用途。该保护系统借助光纤数字通信、数字微波通信技术,将被保护线路两侧电流采样数据及有关信息对传,并辅以两侧数据的计算机同步调整而实现。理论分析与动模试验、型式试验及现场试运行结果表明,保护装置原理先进,动作速度快,可靠性高,抗干扰能力强,结构合理,对微波系统误码率指标要求低。装置可以作为110kV及以上各级输电线路的主保护和后备保护,尤其适用于同杆并架双回线、短线路及因高频通道拥挤而难以采用高频保护的线路。     

异地多端电力系统实时闭环仿真测试系统

介绍一种由位于异地的多个仿真子系统构成的电力系统实时仿真测试系统,该系统采用电磁暂态建模方法,通过基于全球定位系统（GPS）的同步计算技术,实现了精确的异地同步仿真计算。介绍了仿真系统的硬件、软件和实时仿真的计算过程,仿真系统在实时仿真测试过程中通过通信交换异地保护动作信息,修正仿真网络拓扑,实现严格的闭环仿真测试。该系统适用于对变电站的成套线路主保护等装置进行实时闭环测试。     

500kV线路两侧保护动作不一致现象分析

介绍了一起500kV输电线路单相永久性接地故障后线路保护重合闸动作后两侧保护及开关动作不一致的异常事故。事故系统主接线采用3/2接线方式,线路边断路器先重合于永久性故障后,两侧线路保护及开关保护动作出现了不一致,通过对比两侧保护的动作报文及故障录波图,结合两侧保护装置的特性,分析了两侧线路保护及断路器保护动作不一致的原因。     

线路继电保护同步试验系统

对目前电力系统未能进行真正意义的线路两侧继电保护联调试验原因进行了分析,提出了一种利用ＧＰＳ,ＲＴＤＳ及高性能保护暂态试验仪来帝现两侧保护联调及故障分析的新型继电保护同步试验系统。     

线路保护区外故障误动作的分析与处理

介绍某220kV线路保护区外故障误动作事故,对线路保护、故障录波装置和二次回路进行检查分析,判断线路两侧CT极性反接导致保护区外故障误动作。通过使用干电池和直阻测试仪对接入两侧线路保护的6组CT极性进行校验,并对两侧线路保护装置进行极性检验,结果证实了线路两侧CT极性反接是导致线路保护区外故障误动作的根本原因,最后对两侧线路保护进行联调,确保差动回路正确。     

一种新的高压线路保护稳定破坏检测元件

提出了一种新的线路保护稳定破坏检测元件.利用保护安装处的电压、电流和线路阻抗参数,计算出线路对侧母线处的电压.根据保护安装处的电压和计算的线路对侧母线电压之间的相角差,来判断系统是否失去稳定.该元件反映线路两侧电源之间的电势角差,能够准确判断系统是否失稳,及时闭锁距离保护.该元件较直观,实现简单,可以与振荡周期自适应.动模数据仿真验证了新原理的有效性.     

葛洲坝220 kV开关站葛陈线线路保护动作行为分析

2003年8月24日,葛洲坝220 kV开关站葛陈线发生C相瞬时接地故障,线路没有进行重合而直接三相跳闸.该文先简单介绍了葛陈线故障发生时系统的运行工况和各侧线路保护的动作情况,然后通过系列的推导和相关的试验,全面分析了葛陈线两侧线路保护装置在此次线路故障中的动作行为.     

葛洲坝220 kV开关站葛陈线线路保护动作行为分析

2003年8月24日,葛洲坝220kV开关站葛陈线发生C相瞬时接地故障,线路没有进行重合而直接三相跳闸。该文先简单介绍了葛陈线故障发生时系统的运行工况和各侧线路保护的动作情况,然后通过系列的推导和相关的试验,全面分析了葛陈线两侧线路保护装置在此次线路故障中的动作行为。     

Distance relay application testing using a digital simulator

This paper reports on power transmission distance relay application testing using simulated transient waveforms. Power system modeling and test procedures using modern digital simulators are presented. An extensive study of five commercial relays, comparing their application for a 345 kV transmission line, is carried out by performing thousands of one-terminal and synchronized two-terminal transient tests. The digital simulation approach has proved to be an efficient technique. This paper presents a methodology for evaluating distance relay transient performance based on extensive laboratory testing. Important issues regarding application testing are also addressed and investigated in this paper     

1000kV特高压输电线路保护的现状及发展

1000kV特高压输电系统由于其分布电容引起的故障暂态分量与500kV系统有本质的区别,因此研究1000kV特高压输电线路保护首先必须要研究1000kV特高压系统的暂态特性以及与500kV线路保护的区别。文章介绍了目前关于1000kV特高压输电线路保护研制过程中所关注的一些主要问题,如1000kV特高压系统暂态过程,特高压保护的关键技术问题等,对1000kV特高压输电线路保护提出了基于分布式模型的电流差动保护和距离保护测量原理。经过大量的动模试验验证：目前1000kV特高压输电线路保护完全能满足特高压电网安全稳定运行的要求。     

A FAULT LOCATION ALGORITHM FOR TRANSMISSION LINES

ABSTRACT

This paper presents an algorithm for the computation of fault location for a transmission line by means of the voltage and current signals, acquired by the digital distance relays at both the terminals of the line. Based on the proposed algorithm, the fault distance can be calculated accurately and quickly, even though the two digital distance relays are of different types with different sampling frequencies. This proposed fault location method is suitable for the condition that there are communication links between a power grid dispatch centre and the digital distance relays.     

Performance of distance relays on shunt-FACTS compensated transmission lines

This paper presents a study of the performance of distance protection relays when applied to protect shunt Flexible AC Transmission System (FACTS) compensated transmission lines. The objective of this study is to evaluate the performance of distance relays on transmission lines with FACTS devices applied for mid point voltage control. Effect of two types of shunt FACTS devices, Static Var Compensators (SVC) and Static Synchronous Compensators (STATCOM) are studied. The study is conducted in three stages. First the situation is studied analytically, where the errors introduced in the impedance measurement due to the presence of shunt FACTS devices on the line are analyzed. In the second stage, the situation is simulated using transient simulation software, EMTDC. In this method, the response of FACTS devices for different fault conditions and system conditions is also modeled. This method brings out some unique problems that would be experienced by the distance relays due to some specific characteristics of the FACTS devices. Finally, the findings are confirmed by testing a commercial distance relay using a Real Time Digital Simulator (RTDS). The results obtained by testing the commercial relay validate the analytical and simulation studies.     

A new neural networks approach to on-line fault section estimationusing information of protective relays and circuit breakers

This paper proposes a new neural network diagnostic system for online power system fault section estimation using information of relays and circuit breakers. This system has a similar profile of an expert system, but can be constructed much more easily from elemental samples. These samples associate fault section with its primary, local and/or remote protective relays and breakers. The diagnostic system can be applicable to the power system control center for single or multiple fault sections estimation, even in the cases of failure operation of relays and breakers, or error-existent data transmission. The proposed approach has been practically verified by testing on a model power system. The test results, although preliminary, suggest this system can be implemented by various electric utilities with relatively low customization effort     

Performance Comparison of Distance Protection Schemes for Shunt-FACTS Compensated Transmission Lines

This paper presents a comparative study of the performance of distance relays for transmission lines compensated by shunt connected flexible ac transmission system (FACTS) controllers/devices. The objective of this study is to evaluate the performance of various distance protection schemes on transmission lines with shunt-FACTS devices applied for midpoint voltage control. The impact of two types of shunt FACTS devices, static var compensator (SVC) and static synchronous compensator (STATCOM) on the transmission line distance protection schemes is studied for different fault types, fault locations and system conditions. The power system elements and the shunt-FACTS devices with their associated controllers are modeled using RSCAD/RTDS software. The results are based on the performance of commercial distance relays using a real time digital simulator (RTDS).     

Fast isolation of faults in transmission systems using current transients

This paper presents a protection scheme that is capable of very fast isolation of faults in high voltage transmission systems. Proposed scheme comprises set of relays connected through a telecommunication network, located at different nodes of the system. Relays use wavelet coefficients of current signals to identify the fault directions relative to their location. Fault directions identified at different locations in the system can be combined to determine the faulted line (or busbar) and isolate it. A robust single ended traveling wave based fault distance estimation approach is proposed as a backup in case of communication failure. Investigations were carried out using time domain simulations in PSCAD/EMTDC for a high voltage transmission system.     

An accurate digital low-pass filter for transmission line protection

The paper presents a procedure for designing, testing and evaluating digital low-pass filters for the removal of high-frequency transients from transmission line short-circuit voltage and current waveforms, as is required for certain digital distance relays and may be useful in other similar applications. The procedure is based on the ‘trapezoidal’ type of low-pass digital filter which has characteristics that enable low-order digital filters to be achieved. Criteria for the design and optimization of such filters in the foregoing type of application are also presented.     

一种多端继电保护暂态测试方法

介绍了一种基于离线电力系统电磁暂态程序（EMTP）的多端继电保护暂态测试方法。该方法利用EMTP作为测试数据源,在保护实时测试前,根据预计的保护可能动作的情况,用EMTP事先准备好相应的数据;在保护实时测试中,根据保护的实际动作情况,送出相应的事先准备好的保护动作后的电流、电压波形,实现多端保护的闭环测试。整个系统结构简单、对硬件要求低、模拟准确,试验验证是一种有效的继电保护暂态试验方法。