基于S参数的GIS局部放电信号传播特性仿真与实验研究

Simulation and Experimental Study on Propagation Characteristics of GIS Partial Discharge Signal Based on S-Parameter

在气体绝缘开关设备(Gas Insulated Switchgear,GIS)中,由于存在各种类型的绝缘缺陷而使得GIS内部发生局部放电,其产生的电流脉冲会在GIS腔体内激励出特高频(Ultra-High Frequency,UHF)电磁波信号,本文针对局放UHF电磁波信号在GIS结构中的激发、传播和衰减的规律研究不足的现状,对UHF信号在同轴腔体中的波导特性进行了理论分析,利用微波网络中的S21参数反映信号在传输过程中的增益,通过有限元仿真软件HFSS扫频得到了GIS局部放电UHF信号传输特性曲线即S21参数曲线,并在云南永仁500KV变电站进行了现场实测,将实验与仿真结果进行对比,证明了仿真结果的合理性,同时得到了局部放电UHF电磁波信号在GIS典型结构中的衰减特性。利用局部放电UHF电磁波在GIS中的传输特性可以指导UHF传感器在GIS中的布置,提高UHF传感器检测局放信号的准确性。

Gas Insulated Switchgear(GIS)generates partial discharge due to various types of insulation defects.The current pulse generated by partial discharge will excite Ultra-High Frequency(UHF)electromagnetic wave signals in the GIS cavity.Because of the current situation of insufficient research on the excitation,propagation and attenuation of UHF electromagnetic wave signals in GIS structure.In this paper,the waveguide characteristics of UHF signal in coaxial cavity are analyzed theoretically.The gain of signal in transmission process is reflected by S21 parameter in microwave network.GIS partial discharge UHF signal transmission characteristic curve,namely S21 parameter curve,was obtained through HFSS frequency sweep of finite element simulation software.We carried out on-site measurement at the Yongren 500KV substation in Yunnan.By comparing the simulation and experimental results,the rationality of the simulation model was verified and the transmission characteristics of the partial discharge UHF electromagnetic wave signal in the typical structure of GIS were obtained.The transmission characteristics of the UHF electromagnetic wave in the GIS can guide the layout of the UHF sensor in the GIS,and improve the accuracy of UHF sensor field calibration.