振荡型冲击电压下局部放电的检测及干扰分析

PD Detection and Interference Analysis Under Oscillating Impulse Voltage

变压器及GIS等电气设备在投运前往往会经过长途运输、现场组装等环节,这些环节会对设备的绝缘产生潜在的损害,因此现场试验对于设备的安全运行具有重要作用。交流耐压试验及局部放电测量并不能发现设备所有的潜在缺陷,冲击耐压试验及局部放电测量则是对其的有效补充。振荡型冲击电压是一种适合设备现场使用的冲击电压波形,为了研究振荡型冲击电压下局部放电的检测及特性,文中构建了振荡型冲击电压下局部放电检测系统,分析了干扰的来源及干扰抑制措施。研究结果表明冲击电压发生器的干扰是局部放电测量系统的主要干扰源,冲击电压本身的位移电流及发生器球隙动作所产生的高频干扰会对局部放电的测量产生严重影响,采用高通滤波器和基于脉冲时域波形的等效时频分析,可以有效滤除干扰,实现振荡型冲击电压下局部放电的准确测量。

Before the power equipment, like transformer and GIS, is put into operation, there are many factors such as transportation, on-site installation that will take some latent damage to its insulation. Thus the field test is an important step to ensure the safety of power equipment. The AC withstand voltage test and its corresponding partial discharge（PD）measurement are inadequate for the detection of all hidden defects in power equipment. Such inadequacy can be compensated by additional impulse withstand voltage test and its PD detection t. Oscillating impulse voltage is one voltage waveform that is suitable for field test. In order to study the detection and characteristics of PD under oscillating impulse voltage, the PD detection system is established. The interference resources are analyzed and the anti-interference methods are studied in this paper. The study resuhs show that the interferences from impulse generator are the main ones. The displacement current and the high frequency EM wave from generator switcher action will cause serious interferences. By adopting high pass filtering technology and equivalent time-frequency analyses based on waveform time domain feature, the interferences can be effectively eliminated. And PD signals under oscillating impulse voltage can be detected accurately.