GIS绝缘垫片分层间隙中局部放电检测及形成机理研究

Detection and Formation Mechanism of Partial Discharge in Delamination Gap of GIS Insulation Spacer

垫片放电是气体绝缘开关设备(GIS)中最严重的缺陷之一,当SF6气体渗入到垫片微间隙之后,间隙内的气压通常由0 MPa逐渐增大至与SF6气压相同。本文在不同气压(0.02~0.40 MPa)下进行试验,研究间隙长度为50μm时GIS垫片中的局部放电活动,结合不同气压下的局放信号相位特性,分析局部放电(PD)的相对生成速率。结果表明:SF6气压为0.02 MPa时,局部放电脉冲出现在外加电压零点相位(0°和180°)附近,局部放电通过间隙沿环氧树脂表面传播;随着气压的增加,放电剧烈程度增加;SF6气压为0.25 MPa时,PD活动停止。不同SF6气压下,由于产生初始电子崩的机理不同,正极性的PD生成速率低于负极性的PD生成速率。

Spacer discharge is one of the most serious defects in gas insulated switchgear(GIS).When SF6 gas penetrates into the micro gap of the spacer,the air pressure in the gap increases gradually from 0 MPa to the pressure value of SF6.In this paper,the partial discharge activities in GIS spacer were studied under different air pressure(0.02-0.40 MPa)when the gap length is 50μm,and the relative generation rate of partial discharge(PD)was analyzed combined the phase characteristics of partial discharge signals under different pressures.The results show that when the SF6 pressure is 0.02 MPa,the partial discharge pulse appears near the zero point phase(0°and 180°)of the applied voltage,and the partial discharge propagates along the epoxy resin surface through the gap.With the increase of air pressure,the discharge intensity increases.When the SF6 pressure is 0.25 MPa,the PD activity stops.Under different SF6 gas pressures,because the generation mechanism of initial electron avalanche is different,the generation rate of the PD with positive polarity is lower than that of the PD with negative polarity.