GIS局部放电信号及内置传感器检测分析

气体绝缘组合电器(GIS)局部放电不仅激发横向电磁波(TEM),而且会激发横向电场波(TE)和横向磁场波(TM).利用电磁场中的并矢格林函数理论,推导出了GIS中PD信号在任意点激发瞬变电场的计算表达式,在计算GIS中PD激发的电场时,应考虑TEM波和检测频段内所有高次模波的贡献.在实验室GIS模拟装置上,设计了灵敏度及抗干扰能力优于外置传感器的内置传感器,并用天线模型对其进行了频率响应特性分析,最后直接用高参数数字存储示波器测量了由金属突出物缺陷产生的局部放电信号.

GIS Partial Discharge Signal and Its Internal Sensor Detection

Partial discharge electromagnetic waves in GIS propagate is not only in the transverse electric and magnetic(TEM)mode, but also in transverse electric(TE) and transverse magnetic(TM)mode. The paper deduces out the mathematic expressions transient field excited by PD in GIS anywhere by using dyadic Green function theory. The contributions of TEM mode and all high order modes in the detecting frequency scope should be taken into consideration when calculating the electric field excited by PD in GIS. In simulative GIS laboratory, the designed inner couplers are superior to other outer sensors in detection of partial discharge. Inner couplers for the GIS model are developed and their frequency responses are analyzed in antenna model. At last the PD pulses excited by man-made defect are detected by inner couplers using high parameters oscilloscope.