基于特高频法的GIS金属尖端缺陷局部放电检测和分析

Detection and Analysis of Partial Discharge of Metal Protrusion Defects in GIS Based on UHF Method

金属尖刺缺陷作为GIS内部常见的绝缘缺陷之一,严重威胁GIS的安全稳定运行。文中基于特高频局部放电检测方法研究了GIS内部导杆和外壳上金属尖刺缺陷的局部放电特性。在导杆上设计了长度为3.5、6、12 mm的尖端缺陷,在外壳上设计了长度为12 mm的尖端缺陷;通过逐步升压法对不同部位、不同尺寸缺陷下的特高频局部放电信号进行了测量;结合局部放电信号PRPD谱图对不同部位、不同尺寸下的局部放电特性进行了分析。试验结果表明,GIS内部的金属尖端缺陷不同电压下的放电呈现不同的特征,放电首先出现在交流电压负半周,然后出现在交流电压正半周。缺陷的尺寸对放电特性影响显著;不同位置的尖刺缺陷局部放电特征明显不同。

As one of the common insulation defects in GIS,metal protrusion defects seriously threaten the safe and stable operation of GIS.Based on the UHF partial discharge detection method,the partial discharge characteristics of metal protrusion defects on the internal line and the shell of GIS are studied in this paper.A metal protrusion de⁃fects with a length of 3.5 mm,6 mm,and 12 mm are designed on the internal line,and metal protrusion defects with a length of 12 mm are designed on the shell.The UHF PDs under different positions and different sizes is measured by g the step⁃up method.The characteristics of partial discharges at different locations and sizes are analyzed with PRPD spectra.The test results show that partial discharge of the metal protrusion defects in GIS pass through four stages to breakdown;the size of the defect has a significant effect on the discharge characteristics;the local of met⁃al protrusion defects are also effect the discharge characteristics.