冲击电流测试系统中测量误差的试验研究

从影响冲击电流系统测量精度的因素出发,试验研究了系统接地点、转换装置的连接方式及系统自身的电磁干扰等对测量精度的影响。试验证明:采用单点接地、悬浮测量、减小高压引线与转换装置构成的闭合回路包围面积及电磁屏蔽、电源隔离、浪涌吸收等抗干扰措施可提高系统运行的可靠性及冲击信号测量的精度。     

远程雷电流监测系统的开发与实验

地闪雷电流波形的测量对于研究雷电特性以及雷电防护有着非常重要的意义,为测量地闪雷电流波形,介绍了一套远程雷电流监测系统的开发及其应用实验。测量使用自行研制的自积分式Rogowski电流探头测量雷电流信号,可测量雷电流幅值达50kA;以ARM处理器为核心的采集系统采样速率为40MHz,采样精度为12位,正负极性触发,存储容量达32MB,可一次性存储64次测量结果;信号传输使用光隔离传输系统,提高了系统的抗干扰能力;设计实现了系统数据的远程访问。针对整套测量系统进行的模拟实验和标定结果表明,整套系统的动态性能良好,满足雷电流测量的需要.     

变电站直流系统交流侵入问题的分析与对策

对于变电站直流系统的交流侵入问题缺乏有效的解决方案。介绍了变电站直流系统交流侵入现象,分析了交流侵入对变电站直流系统的危害,针对现有变电站直流系统抵御交流侵入能力较差的问题,提出了改进方案,通过仿真和现场实验证明了这一改进方案的可行性。     

绝缘子泄漏电流在线监测系统的联网方案与实施

目前,在新疆地区已经安装了13台由西安金源电气有限公司研发的变电站绝缘子泄漏电流在线监测系统,通过系统联网的方式可将新疆各变电站采集的泄漏电流、脉冲频次以及环境条件等数据传送到中心数据库,以便深入研究绝缘子污秽与泄漏电流之间的关系,有助于实现绝缘子污秽的状态清扫.     

电力计量系统分流窃电分析与建模

提出了高压电力计量系统电能表电流线圈分流窃电故障检测模型.首先通过分析,得出电流互感器二次绕组端电压和通过电能表电流线圈的电流二者比值与电能表电流线圈分流窃电故障有密切的关系,及其与损失电量之间的关系.其次,设计用于电流互感器二次绕组端电压和通过电能表电流线圈的电流二者比值变化的故障检测模型,最后进行了仿真研究,以证明模型对故障检测的有效性.     

基于PLC的配电网电容电流测量装置的设计与实现

谐振接地系统电容电流的准确测量决定了消弧线圈的补偿效果,而采用最大位移电压法对系统电容电流进行测量的关键是准确找到中性点最大位移电压。为此基于可编程逻辑控制器PLC辅以相关的外围电路,设计了电容电流测量装置,并对自动跟踪系统运行方式、闭环控制测量电容电流等软件的设计思路进行了说明。测量装置在10 kV模拟配电网上的实验结果表明,该装置能够准确测量系统的电容电流,并能够实时监测中性点位移电压、消弧线圈回路电流以及正在运行的馈线数目,根据运行方式变化特征,灵敏准确地跟踪系统的运行方式,提升了消弧线圈的补偿效果。     

电流环采样时间对伺服系统快速性影响的研究

文章从理论和实践两个方面研究了电流环的采样时间对于高性能、全数字伺服系统的快速性的影响,并给出了可供工程实际参考的选择电流环采样时间的方法.     

Short‐circuit current calculation and performance requirement of HVDC breakers for MMC‐MTDC systems

To evaluate the performance requirement of high‐voltage direct current (HVDC) breakers for modular multilevel converter (MMC)‐MTDC (multi‐terminal high voltage direct current) systems with high efficiency, the equivalent model for calculating the maximum short‐circuit current is presented in this paper. First, the short‐circuit current is decomposed into the steady‐state component and the fault component according to its physical dynamics. Second, the steady‐state component is determined by solving the direct current (DC) network; the fault component is calculated by an equivalent network in which the converters are replaced by a reactance, a resistance, and a capacitance in series. Then, the complete procedure for evaluating the performance requirement of HVDC breakers is described based on short‐circuit current calculation. Verifications have been carried out based on a three‐terminal 800 MW/±400 kV bipolar MMC‐MTDC system. The results show that the proposed methodology is efficient and effective. Lastly, based on the same system, the performance requirement of HVDC breakers and the influence by the sub‐module (SM) capacitance and the smoothing reactor have been studied with the proposed methodology. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Development of time comparison equipment for ETS‐VIII satellite

Engineering Test Satellite VIII (ETS‐VIII) is planning to be launched in 2005 for fundamental studies on satellite positioning technologies and is the one first to have installed a highly precise cesium clock in Japan. To measure the clock offset between the satellite and the TCE earth station, Time Comparison Equipment (TCE) has been developed by NICT. The TCE will be used to measure both code and carrier phases and this system will improve two‐way time and frequency transfer. This equipment makes it possible to compare two clocks with high precision. Moreover, TCE and TCE earth stations have abilities to remove the delay caused by terrestrial ionosphere and that between the receivers and transmitters. We estimated measurement precision in code and carrier phases. Furthermore, from the examinations using TCE‐EM (Engineering Model), we confirmed that TCE is able to measure the clock phases with a subnanosecond precision by code phase observation and a precision of a few picoseconds by carrier phase observation. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(3): 61–71, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20385     

并联型有源电力滤波器的安全保护系统设计

安全保护系统的设计是有源电力滤波器实用化的一项关键技术.并联型有源电力滤波器的安全保护体系可以划分为所用绝缘栅双极晶体管(IGBT)自身保护、系统异常和故障条件下的紧急保护以及正常工作时的预防保护三大部分.对三相四线制四桥臂有源电力滤波器的预防保护措施进行了深入研究,提出了一套简单、有效的投入流程和2种输出电流限幅算法.仿真和实验表明了这些保护措施的有效性,能够使得有源电力滤波器在保证自身安全的前提下充分发挥补偿作用.     

A new model reference adaptive control for linear time‐varying systems

Recent results on the adaptive control of linear time‐varying systems have considered mostly the case in which the range or rate of parameter variations is small. In this paper, a new state feed‐back model reference adaptive control is developed for systems with bounded arbitrary parameter variations. The important feature of the proposed adaptive control is an uncertainty estimation algorithm, which guarantees almost zero tracking error. Note that the conventional parameter estimation algorithm in the adaptive control guarantees only bounded tracking error. Copyright © 2000 John Wiley & Sons, Ltd.     

特高压系统中的短路电流直流分量与零点漂移

结合1000 kV特高压试验示范工程及规划的中国特高压电网,研究了交流1100 kV断路器瞬态问题中的短路电流直流分量衰减时间常数及交流电流过零点的漂移现象,在此基础上提出了我国交流1100 kV特高压断路器的工作条件建议,如特髙压断路器试验的短路电流直流分量衰减的时间常数等。     

氧化锌避雷器阻性电流测量仪的研制及其应用

分析比较氧化锌避雷器的几种测量方法,指出国内外各种ＭＯＡ阳性电流测量方法及装置存在的问题,提出一种新的测量方法－－投影法,根据该原理研制出ＭＯＡ－ＲＣＤ型阳性电流测量仪,并介绍原理及应用情况。     

一种全局收敛的时滞连续系统零极点辨识算法

针对一类时滞连续系统的模型参考自适应递推辨识算法, 运用微分中值定理,在参数不确定性的情况下进行了辨识算法的收敛性分析。通过对包括增益、时滞和实零极点在内的参数不确定性所进行的收敛性讨论, 提出了一种对模型误差进行低通滤波的改进算法, 以改善辨识算法的收敛效果     

高压并联电容器在线监测系统灵敏度及可靠性研究

高压并联电容器在长期运行中,由于缺陷、故障较多,而目前电网检修运行方式无法有效实现提前预判设备故障,以致易出现单台电容器故障扩大为整组故障,存在较大的设备安全运行隐患.因此提出了基于对温度值、电容值和不平衡电压进行检测的高压并联电容器在线监测方法,并对其灵敏度及可靠性进行了研究.运行结果表明该系统对提高电容器可靠性及防止发生电容器故障具有重要的实际意义.     

工频试验变压器高压绕组高电位电流测量系统研制与应用

目前对工频试验变压器的常规测量均为稳态工频参数,未涉及试验变压器高压绕组高电位电流的暂态状况。研制了一套基于Rogowski电流传感器和光电传输技术的高电位电流测量系统,可测量最大冲击电流峰值1 000 A,最大工频电流有效值6 A、频率范围50 Hz~20 MHz;进行了频率响应试验、工频小电流和冲击大电流的性能试验,实测了绝缘子工频闪络时和GIS隔离开关开合感性小电流试验时流经试验变压器高压绕组的电流波形。通过试验数据分析了高陡度暂态电流对变压器的绝缘损伤和测量的意义,探讨了通过比较测得的暂态电流最大陡度以衡量试验变压器保护措施有效性的方法。该系统可为衡量试验变压器保护措施的有效性、改进试验回路以及试验变压器损伤、故障等相关的研究提供参考数据,避免盲目使用造成试验变压器绝缘损伤,对保障其安全运行和科研研究具有重要意义。     

华东电网功角遥测系统的应用及展望

针对系统稳定运行及分析的实际情况,回顾了同步相量测量技术,介绍了华东电网ADX3000多功能功角实时监测系统的应用情况,并对ADX3000功角监测系统的扩展及应用作了较详细的探讨.     

三相四线制不对称系统中有源滤波器指令电流的综合产生与补偿

应用双ip-iq变换检测法与乘正弦信号法相结合,精确分离出基波各部分分量和谐波分量。根据负载的变化,控制有源电力滤波器的补偿指令电流,调节有源电力滤波器的输出功率,从而提高有源电力滤波器的利用效率,并降低有源电力滤波器的容量。仿真结果证明了该方法的正确性和有效性。     

电涡流式电缆绝缘偏心在线测量系统的研究

电缆绝缘偏心不仅造成了材料的极大浪费,而且影响电缆的性能参数。对电缆绝缘偏心测量系统展开研究以实现电缆绝缘偏心的在线检测。首先对涡流传感器进行等效电路分析,在此基础上分析了由电感、电容谐振电路构成的载波信号发生电路,并通过微调电容获得了标准频率的载波信号;传感器输出的测量信号是中频的交流模拟信号,在下位机系统设计了鉴幅、滤波、放大电路,将测量信号转化为模数转换器可以接受的直流信号。系统采用12位模数转换器TLC2543实现模数转换,使得转换误差达到1／4095,可以满足测量的精度。     

Rocket‐triggered lightning current waveforms in winter and investigation of extra‐fast current change

Since 1986, the authors have been taking part in triggered lightning experiments in winter, at Okushishiku, Ishikawa, for the purpose of observing the entire lightning current waveforms with coaxial shunt resistors and an electro‐optical measuring system. Extra‐fast current changes of the order of 1,000 kA/μs were recognized by sharp pulse records superposed on the positive current waveform obtained by a shunt resistor of relatively high residual inductance. This was not the case with a resistor of lower inductance. Furthermore, a positive lightning current waveform which looks like the composite result of bi‐polar discharges has been observed by an advanced measuring system of high performance. This paper deals with these current‐related topics of triggered lightning discharges, which will be analyzed hereafter in detail. © 1999 Scripta Technica, Electr Eng Jpn, 128(2): 18–23, 1999