基于套管屏蔽环的开关柜脉冲电流法在线局部放电检测系统

局部放电检测的脉冲电流法具有灵敏度高、信息丰富、抗干扰性较差的特点,通常应用于电力设备的离线试验中。针对脉冲电流法在线应用的技术要求,研制了基于套管屏蔽环的脉冲电流法局部放电在线检测系统。利用开关柜、环网柜中的对接套管提取局部放电脉冲,并设计配套检测阻抗对其进行参数匹配和仿真优化,同时在10 kV开关柜实验平台上验证了所研制检测系统的有效性。仿真与试验结果表明,研制的检测系统能够实现开关柜局部放电的在线脉冲电流法测量及视在放电量校准,同时有效地对局放源进行相位分辨,可以在对输出局放脉冲保持至少10×10^4次/s分辨率与较高幅值的同时对10 kHz及以下低频干扰产生至少40dB的衰减.运行环境下能够有效地进行局放脉冲提取及故障诊断.为开关柜、环网柜的局部放电在线监测提供了一种新思路。

Pulsed Current Partial Discharge Online Detection of Switchgear Based on Bushing's Shield Ring

The pulse current method for partial discharge detection has the characteristics of high sensitivity,rich information,and poor anti-interference.It is usually used in offline test of power equipment.This paper first discussed the technical requirements of pulse current method for online application,and then developed a pulse current partial discharge on-line detection system based on bushing’s shield ring.The butt bushings in switchgear and ring main unit was used to extract partial discharge pulses,and the detection impedance was designed to performe parameter matching and simulation optimization.Then the effectiveness of the developed pulsed current partial discharge detection system was verified on the 10 kV switchgear experimental platform.Simulation and experimental results shows that the developed detection system not only realizes the on-line pulse current method measurement and apparent charge calibration of partial discharge in switchgear,and effectively distinguishes the phase which the partial discharge occurs,but also maintains at least 10×104 times/s resolution and high amplitude for the output partial discharge pulse,and at least 40 dB attenuation for low-frequency interference of 10 kHz and below.It can effectively perform partial discharge pulse extraction and fault diagnosis in the operating environment,which provides an idea for the on-line monitoring of partial discharge in switchgears and ring main units.