工频相位是局部放电监测进行模式识别的重要基础.目前GIS局部放电监测设备中局部放电类型识别率较低,在三相共筒式GIS中问题更加突出.针对此现象,提出一种基于工频同步信号的三相共筒式GIS局部放电识别方法.在不改变现有工频同步信号接入的前提下,通过工频同步信号触发局部放电信号的采集,并将其通过移相因子转换为其他相局部放电数据,分别与系统中局部放电类型数据库比对,将识别率最高的类型输出,从而达到模式识别的目的.所述方案实现简单,具有应用灵活和故障类型识别率高的特点.

介绍了在现场进行电厂1 000 kV特高压变压器局放测量试验技术与实施情况,采用变频电源装置加补偿电抗器的方法能很好地解决现场进行试验所需电源容量大的难题,针对现场不同干扰采取相应抗干扰措施,效果明显.

配电系统电容电流过大,如不采取措施,容易产生间歇性弧光接地过电压,而配电线路复杂,应通过实测掌握相关情况.文章介绍配电系统电容电流的常用测量方法,比较其优缺点,并应用中性点外加电容法、附加电容法及中性点外施异频信号法,测量某变电所35 kV配电系统电容电流.

220 kV输电线路跳闸对电网供电可靠性影响较大,这其中雷击引起的占较大比例,分析认为绕击是安徽电网220 kV输电线路雷击跳闸的主要原因,避雷线保护角、杆塔高度、地形、杆塔型式等对绕击都有影响.文章还对雷击发生的时间、雷电定位系统使用、重合闸成功率进行了分析.

目前开关柜局部放电带电检测主要采用声电联合技术,且以巡检方式为主,因此本文研究设计一种监测系统,系统通过内置式的TEV传感器和超声波传感器监测局部放电信号并以成对方式连接到采集单元,由采集单元通过特定的Modbus规约上传到后台进行数据管理分析,有效解决了目前巡检方式存在的多种不足.且通过实验室测试运行,结果表明这种方案能有效监测开关柜局部放电状态.

文章阐述了GIS合闸电阻断口失步开断、关合型式试验的原理和方法,并介绍了一起GIS该型式试验过程中发生放电故障的经过以及故障后设备解体和处理情况,就其故障原因进行了深入地分析,最后提出了合理的建议和应改进的防范措施,以杜绝类似故障再次发生.

某省某降压运行线路,因遭受远区雷击发生跳闸事故,线路绝缘未闪络,站内避雷器损坏。通过对线路雷击跳闸分析、避雷器解体检查以及仿真计算,判断线路出线避雷器损坏的原因是降压运行线路因线路参数发生变化,在特殊工况下承受较大操作冲击电流,超过避雷器所能承受能量,使避雷器击穿。通过理论和电磁暂态仿真计算,提出降压运行线路,应校核避雷器标称放电电流和线路放电等级,合理选择避雷器的技术参数,提高线路运行可靠性和避雷器使用寿命。

Aiming at the usually used ultrasonic method for GIS partial discharge detection,an ultrasonic signal testing and measurement system is constructed.A new pulse edges extraction method based on the moving window variance threshold is proposed and used.The start and end position of the ultrasonic partial discharge pulse waveform can be found out from the de-noised data,the pulse waveform can be easily extracted using the method.This provides a foundation for the extraction of ultrasonic signal features and defect pattern recognition.

Capacitor damage is a frequent occurrence in the substation,which,especially in switching shunt capacitor by vacuum circuit breaker,affects seriously safe operation of shunt capacitor.For repeatedly multi-phase restrike fault of shunt capacitor during opening operation in this paper,the process is simulated by ATPDraw simulation procedure based on data of wave recorder and disassembly inspection of capacitor.The analysis results indicate that the main reason of the capacitor dielectric breakdown is the overvoltage and inrush current which caused by multiple restrikes during the vacuum circuit breaker opening;and reduce reignition rate of vacuum circuit breaker switching capacitor is crucial to reduce the fault of shunt capacitor.

In order to fully understand the characteristics of lightning activity and thereby supply important reference for plan and construction of the Anhui Grid as well as lightning protection design, massive detection data from 2005 to 2009 gained by Anhui Lightning Detection Network are statistically analyzed by the grid method in this paper. The time and space distribution of lightning activity and distribution of cloud-ground flashes current amplitude in Anhui province are presented. On the basis of the results, the lightning performance of shielding failure of a typical transmission line is studied with lightning parameters recommended by regular method compared with that with statistical lightning parameters. The results show that the lightning activity in Anhui province mainly happens in south-east areas. In addition, the statistical ground flash density is higher than that recommended by regular method and the median current of the cumulative probability fitting expression obtained in this paper is lower than that of the fitting expression format adopted by IEEE. The shielding failure rates calculated with statistical lightning can better meet the operational experience.

The positioning and monitoring principles,main functions,and technical indices of the lightning monitoring system for Anhui Power Grid were presented.Based on large amount of lightning information obtained,the fundamental data and practical method for guiding anti-lightning design,technical retrofits,and operation were achieved.

To understand overvoltage change at a 500 kV autotransformer neutral when the neutral is grounded from directly to through a small reactance,the overvoltage at autotransformer’s neutral and entrance is calculated respectively by ATP-EMTP,and the overvoltage for adopting small reactance grounding is analyzed to determine overvoltage protection and insulation coordination.It is concluded that the insulation level of the autotransformer in 500 kV Feixi substation can keep stable after its neutral is grounded through a 5 Ω reactance under protection of MOA.This conclusion will contribute to the solution to the problem that single phase short-circuit current exceeds the switch rate breaking current in the Feixi 500 kV grid.

According to the phenomenon of resonance occurred in 500 kV long distance compact transmission line under some operation modes in Anhui Power Grid, due to the disposition of shunt and neutral reactor, the paper introduced a kind of software to adopt EMTP electromagnetic transient calculation. The over-voltage calculation and analysis of the basic operating conditions under the start-up mode and the conventional condition after putting into service were carried out, which can reach to change the start-up mode and play the role of completing safety start of line.

利用雷电定位系统(LLS)分析2002、2003年安徽电网500 kV输电线路雷击跳闸后,得出绕击是500 kV输电线路雷击跳闸的主要原因.提高线路绝缘水平、减小避雷线保护角及杆塔接地电阻等措施是线路防雷工作的重要措施,LLS对于雷击故障点的查找、事故分析都有重要指导作用.

介绍了一次220 kV氧化锌避雷器(MOA)红外测温异常的处理,通过对异常MOA的带电检测、停电试验、解体检查的分析,指出红外测温、阻性电流测量可及时准确发现MOA受潮故障.