负极性振荡雷电冲击电压下SF_6尖板模型局部放电特性

Partial Discharge on SF_6 Needle-Plane Defect under Negative Oscillating Lighting Impulse Voltage

为了深入研究尖板模型振荡雷电冲击电压下局部放电特性,首先搭建了振荡冲击电压发生器,产生符合IEC 60060-3标准的振荡型雷电冲击电压,基于特高频法和脉冲电流法,建立了冲击电压下局部放电测量系统,进而构建了SF6尖板模型,对负极性振荡雷电冲击电压下局部放电进行了测量,对比了特高频法和脉冲电流法测量局部放电的灵敏度,分析了放电时延、放电幅值、放电数目和放电相位随外施电压的变化规律。结果表明:特高频法测量灵敏度更高,适合在气体绝缘组合电器(GIS)现场冲击耐压试验中使用;局部放电集中在外施电压各波峰附近;随着外施电压的升高,放电时延和放电起始相位急剧减小,放电结束相位则稍有增大;各周期放电幅值和数目随波峰电压的升高而线性增加。进一步分析表明,在负极性振荡雷电冲击电压下,局部放电的产生和发展可用金属电极表面发射、负离子场致碰撞脱附和电晕稳定化作用进行很好的阐释。研究成果有助于GIS现场冲击耐压试验中局部放电的检测与分析。

Aiming at partial discharge（PD）characteristics on needle-plane defect under oscillating lighting impulse voltage,an oscillating impulse voltage generator was constructed,and the oscillating lighting impulse waveform was obtained,which meets the requirement of IEC60060-3standard.The partial discharge detecting system was built based on UHF detection and pulse current detection.A needle-plane defect model was designed and its partial discharge under negative oscillating impulse voltage was measured. The measurement sensitivity of UHF detection was compared with that of pulse current detection.The relations of the applied voltage with statistical time lag,PD amplitude,PD time and PD phase distribution were analyzed.The results show that UHF detection with higher measurement sensitivity is suitable for on-site impulse voltage withstand test;PD appears around each wave peak of the applied voltage;withthe increasing applied voltage,statistical time lags and starting phase decrease rapidly,while the ending phase increases slightly;with the increasing peak voltage in a period.PD amplitude and PD time in each oscillating period both increase linearly.Further analysis indicates that the occurrence and development of PD under negative oscillating lighting impulse voltage can be well explained by electron emission from metal surface,field detachment from negative ions,and corona stabilization effect.This approach is valuable for PD measurement and analysis in on-site impulse voltage withstand test for GIS.