一起220 kV变压器局部放电试验异常情况分析

对一起220 kV变压器现场局部放电测试结果进行分析,采用多端子校正-多端子测量的方法对变压器局部放电位置初步定位,结合变压器高压绕组局部放电表征参数进一步分析,最终确定油中气泡放电为变压器局部放电测试结果异常的原因,提出了现场处理方案,并对江苏地区冬季安装变压器的流程提出建议.     

一起换流变压器现场局放异常的分析与处理

记录了一起特高压直流工程中换流变交接试验时发现局部放电信号的分析及处理过程。介绍了换流变现场局部放电试验方法,发现局部放电后的定性、定位方法,局部放电产生的原因以及处理结果,对换流变现场局部放电的测试与诊断有一定参考意义。     

GIS内部放电缺陷的综合诊断方法与实践

本文介绍了GIS(Gas Insulated Switchgear)内部局部放电缺陷的综合诊断方法(超高频局部放电检测、超声波局部放电检测、SF6分解物测试),通过工作中大量实践对几种方法的性能做了对比与探讨。以现场一起故障的定位和分析为例,提出了SF6分解物测试和其他两种方法可以互相佐证,提高检测准确性。最后对局部放电检测技术的深入应用进行了展望。     

基于UHF法的SF_6断路器局部放电测试系统在组合电器上的应用

介绍电气设备局部放电特点和局部放电测试系统的现场要求、总体设计,以保定220kV张丰变电站126kV GIS断路器局部放电带电检测为例,从现场测试、放电定位功能、放电类型等方面进行分析,验证该系统的有效性和实用性。     

500 kV变压器现场局部放电异常分析

变压器现场局部放电试验异常是现场交接试验中最常见的问题。以一起500 kV变压器现场交接试验时局部放电异常的分析与处理过程为例,介绍局部放电试验的试验背景与方法,描述局部放电缺陷处理情况。在缺陷判断过程中,通过对变压器的高、低压线圈进行双边、首端、尾端加压试验,测量局部放电传递比,判断局部放电的类型及发生的大体方位,并给出调整低压引线与周围油箱的距离、检查引线冷压位置等处理措施,提供了一套完整的局部放电异常问题解决方案,为现场局部放电试验异常处理提供一定的借鉴。     

基于甚宽带脉冲电流法的局部放电检测系统

局部放电的检测与分析是评价电力设备绝缘状况,发现早期故障的一种有效方法.与传统的脉冲电流法相比,甚宽带测量方法可以获取更多的局部放电信息,有助于提高测量的灵敏度和抗干扰能力.本文介绍了基于甚宽带脉冲电流法的局部放电检测系统,研究了传感器特性、脉冲分离技术和定量方法.并在实验室和现场对该系统的性能进行了测试,结果表明该系统具有灵敏度高和抗干扰能力强等优点,可以有效地应用于局部放电的现场检测和在线监测.     

振荡波测试技术在电缆局部放电检测中的应用

介绍振荡波电压的产生和局部放电定位原理,通过模拟缺陷试验分析判断电缆局部放电的精确位置,结合现场测试实例验证了OWTS振荡波测试技术在电力电缆局部放电检测中的实用性.     

特高压并联电容器局部放电试验技术研究

分析了电力电容器局部放电产生的原因及影响,针对特高压用大容量并联电容器提出了脉冲电流法局部放电试验方法,研制出了适用于现场测试的局部放电试验设备。通过放电量校准及现场试验,结果表明脉冲电流法电容器局部放电检测方法灵敏度高,适用于特高压并联电容器现场局部放电检测。     

大型电力变压器局部放电试验干扰排查

介绍不同干扰信号对局部放电的影响,提出局部放电试验系统外部干扰和内部干扰的排查方法,结合一起500kV变压器现场局部放电试验中的干扰排查实例,分析试验干扰排查的过程及干扰源判断方法,为现场局部放电试验干扰信号处理提供借鉴。     

中低压电缆振荡波局部放电的现场测试

2011年浙江省电力公司在省内开展了电缆振荡波局部放电测试和定位(OWTS)试验,介绍了振荡波检测原理和现场测试步骤,对一起10 kV电缆中间接头局部放电现象进行了详细分析,并总结了经验和注意事项。     

Partial discharge detection in cables using VHF capacitive couplers

In order to detect and locate partial discharge (PD) activity within HV cables and in particular cable joints, the feasibility of using a very high frequency WHO capacitive coupler technique has been investigated. In addition, an alternative PD offline test method for cable joints or cable sections within long cable systems has been developed. By energising the joint or a short section of the cable screen only this method has the advantage of reducing the power supply requirement of the test source. The application of capacitive couplers for this PD offline test method has been investigated. In order to use this approach there must be an insulation gap between the coupler and the outer sheath of the test cable. The effect of this gap on measured sensitivity has been investigated experimentally and through the use of a simulation model. Obtained results are in good agreement. Cross-correlation techniques have been implemented to automatically estimate the signal time of flight from different-coupler outputs. Methods of calibrating the coupler applied to the alternative PD offline test method have also been investigated.     

Research on influence of high-voltage cable un-homogeneities on process of short waves distribution

The partial discharges (PDs) inside of high-voltage cable insulation negatively influence cable service lifespan. Therefore timely detection and localization of affected areas with the weakened electric insulation is a vital question, in particular—according to measured values of PD parameters before they reach the dangerous stage of their development. Electrical cable is a circuit with the distributed parameters for current and voltage waves, initiated by local PD which changes their starting values with time. These changes can be taken as informative parameters for solving problems of localization of the defect and evaluation of dangers to cable's performance. Clear and detailed understanding of PD pulse distribution features in power cables is the basis for correctly solving cable diagnostics tasks with non-destructive approaches. This article uses the mathematical model of a power cable on the premises of cable equations. The model allows for modeling of wave processes in a non-uniform electric circuit (at sudden change of longitudinal parameters) in view of repeated reflection of PD waves from the ends and un-homogeneities of an electric cable. Results of mathematical modeling were compared to the data received from physical model of 110 kV XLPE electric cable. The cable physical model is realized with the help of the chained circuit consisting of 15 quad-poles. This document shows results of measurements and modeling of wave process caused by PD. Also, details of the wave process as dependent on time and frequency, and practical use of measurements of PD for cable insulation control, are discussed. Practical measurements show high degree of accuracy with regards to the data generated by theoretical model analysis.     

一种可用于电缆局部放电检测的串联谐振系统

交联聚乙烯电缆正日益取代传统的架空线路,逐渐成为城市输配电网络的重要构成部分。复杂的电力电缆网络对电缆的故障检测技术提出了更高的要求,然而传统的串联谐振系统存在大量的脉冲干扰,导致其只能进行耐压试验而不能用于局部放电检测,难以满足电缆绝缘状态评估的需要。为了实现对电缆绝缘状态全面且可靠的评估,文中提出了一种改进的串联谐振系统,利用等脉宽调制技术和时域开窗技术滤除脉冲干扰,实现了在开展电缆耐压试验同时进行局部放电检测的功能,并用实验室试验验证了系统的有效性。     

局部放电信号传播特性在电缆局部放电测试中的应用

就深圳供电局某110 kV电缆线路2号中间接头进行局部放电检测时发现的疑似局部放电(partial dis-charge,PD)信号展开跟踪测试和分析。测试采用了脉冲电流的测试方法,首先通过2号中间接头所检测到的疑似PD信号进行频率特征及其发射波(回波)特点的分析,之后对全线路的各个中间接头测试和分析,最终通过分布在全线路各点的同一信号的传播衰减特征,确认疑似PD信号来自EB-A终端架空线电晕放电。该方法可及时发现电力电缆线路潜在缺陷隐患,保障线路安全可靠运行。     

高压电缆终端在线局部放电测试分析

介绍了综合运用高频(high frequency,HF)与超高频(ultrahigh frequency,UHF)2种测试技术成功实现对运行中高压电缆终端局部放电进行测试的实例.方法是首先利用UHF检测系统初步巡检,然后根据现场情况分别采用多种信号检取方式从被试电缆终端取样测量信号,进行HF深入测量.测试的结果:获得了...     

110kV交联电缆交接试验中带电局放检测及干扰抑制分析

笔者介绍了某新建变电站工程110 kV交联聚乙烯电缆交接耐压试验中实施局放检测的过程,通过对谐振系统加装屏蔽及抑制措施,在局放测试系统中设置滤波和检测频带,减少背景噪声干扰,提高了检测系统信噪比。检测结果证实了搭建的局放检测平台和干扰抑制方法对现场检测电缆局放的有效性,为今后开展现场电缆局放带电检测提供参考。     

超声局放测量在电缆分支箱局放检测中应用

局部放电(简称局放)试验是验证交联聚乙烯绝缘电力电缆(简称交联电缆)及电缆附件质量的重要环节。脉冲电流法一直是目前实验室内进行局放检测的主要方法,该方法在技术上已经较为成熟,且由于实验室内屏蔽效果好,背景干扰低,因此对电缆或电缆附件进行出厂试验之一局放检测效果较好,但是对于运行的电缆或电缆附件进行局放检测,或对已经发现存在局放的电缆回路中进行局放定位,往往需要复杂的波形分析或数学计算。通过利用超声局放测量仪器,对运行前和运行中10 kV交联电缆和电缆分支箱等电缆附件分别进行了局放测量,方法简单易行,取得了较好的效果。     

110kV电力电缆故障定位及分析

随着城市建设的高速发展,电力电缆在各行各业都得到广泛的应用,但其故障率也逐年增加。文中以110 kV XLPE(交联聚乙烯)海底电缆故障及其修复过程为例,从电缆故障定位的基本原理出发,介绍利用回波法、二次脉冲法等方法检测电缆故障的全过程,分析故障定位过程中出现的问题,并通过现场试验进行了验证,证明了推论的准确性。     

Examination and location of partial discharge sites in severelyaged underground distribution cables

This paper presents the results of laboratory investigations of partial discharge (PD) in field aged XLPE underground power cables. PD measurements were made on sixty-one cable samples over a three year period. When PD was detected, the magnitude was measured and a site location was determined. PD site locations were predicted using time delay estimations between PD pulses arriving at opposite ends of the test cable. Fourteen of the samples tested had detectable levels of PD. Some of these PD sites extinguished during the measurement period and were returned to rated voltage aging. When samples had continuously active PD sites, they were either dissected or returned to the aging test. Four sites of this type were found allowing two for dissection and two for aging. Seven of the samples failed after PD measurements. All seven failed near the predicted PD location. During the PD testing, no test cables contained PD which initiated at or below operating voltage. When PD detection equipment was monitoring cables which failed, the failures occurred from 2 to 80 minutes after the presence of PD pulses was detected     

基于物联网的110 kV电缆管井智能监测系统建设与应用

电力电缆在城市供电系统中起关键作用,电缆管井用于电缆接头制作或检修施工使用。日常运行过程中,电缆管井可能会出现电力电缆本体或中间接头过热,环境温度过高、水位过高等异常状态,大量非正常烟雾及非法入侵等现象也威胁着电缆供电系统的可靠性。介绍了一套用于对110 k V电缆管井智能监测的系统,包括智能感知系统、监控主机系统及在线监测终端系统。首先,介绍了由多智能传感器组成的感知系统,通过Lo Ra技术同井上监控主机无线通信,数据推算及实际测试结果表明本套系统依靠电池能够满足长时间续航要求;然后,介绍了多功能后台远程监测终端系统,后台系统基于物联网NB-lo T技术无线连接远端监控主机。本套系统在深管井中得到应用,能实时感知系统运行健康状况,极大便利运行维护人员,对确保电力电缆安全运行,提高供电可靠性具有重要意义。