550 kV GIS盆式绝缘子多气泡放电的测试与诊断

Test and Diagnosis of Multiple Voids Discharge for 550 kV GIS Insulation Spacer

为了提高现场气体绝缘全封闭组合电器(GIS)绝缘缺陷的诊断能力,提升特高频(UHF)法在现场的检测经验,该文对一起550 kV GIS盆式绝缘子多气泡放电开展了详细的测试与诊断。首先在现场利用UHF法检测发现了550 kV GIS盆式绝缘子的异常信号,该信号呈气隙放电特征。对该盆式绝缘子更换返厂后开展了耐压、局部放电、雷电冲击、X射线探伤等试验,同时采用UHF法和脉冲电流法对盆式绝缘子局放信号进行检测,并对比了雷电冲击试验前后放电特性的变化。最后利用时差定位统计和多源放电分离方法开展了进一步的诊断分析。结果表明:该盆式绝缘子内部存在8个气泡,呈线性状分布,UHF和脉冲电流法两者信号幅值正相关;随着电压的升高,放电谱图逐渐由单气隙放电转为多气隙放电特征;在耐受雷电冲击后,盆式绝缘子的局部放电起始电压下降,熄灭电压不变,相同电压下UHF信号幅值与局放量变大;时差统计和多源分离表明,该盆式绝缘子UHF信号呈多源时差和聚类特征,与X射线结果一致。该文研究结果可为GIS UHF检测与诊断提供现场经验。

In order to improve the diagnose ability of insulation defects of gas insulated switchgear(GIS)and improve the detection experience of ultra-high frequency(UHF)method in the field,detailed tests and diagnosis of multiple voids discharge of 550 kV GIS insulation spacer were performed in this paper.Firstly,the abnormal signal of 550 kV GIS insulation spacer,presenting a characteristic of void discharge,was detected on field by the UHF method.After the replacement of the insulation spacer,the tests of withstand voltage,partial discharge,lightning impulse and X-ray detection were employed to investigate the void discharge of insulation spacer.Meanwhile,the UHF and pulse current methods were used to detect the PD signal of the insulation spacer.The discharge characteristics were compared after the lightning impulse.Finally,further diagnostic analyses were carried out by using time difference location statistics and multi-source discharge separation methods.The results show that there are 8 voids in the insulation spacer,which are linearly distributed.The amplitudes of the signals are positively correlated with UHF and pulse current method.With the increment of applied voltage amplitude,the discharge spectrum gradually changes from single void discharge to multiple voids discharge.The partial discharge initial voltage decreases and the extinguishing voltage does not change after the lightning impulse.The UHF signal amplitude and discharge amount will increase under the same voltage after the lightning impulse.The time difference location statistics and multi-source separation indicate the insulation spacer behaves as multiple discharge source characteristics,which is consistent with the X-ray results.The results can provide field experience for GIS UHF detection and diagnosis.