局部放电电磁波在GIS中传播路径的分析

Analysis on the Propagation Routes of Electromagnetic Waves of Partial Discharge in GIS

为进一步揭示GIS中局部放电电磁波的传播特性,采用FDTD方法仿真分析了GIS中局部放电产生的电磁波信号的传播路径及其与信号波形之间的关系并在真实GIS中进行了相关试验研究。仿真和试验结果均表明局部放电电磁波在GIS中的传播路径与局部放电源的位置相关,且检测的电磁波信号波形受电磁波传播路径的影响也不尽相同。局部放电源靠近GIS内导体时,检测位置φ不同时的电磁波信号波形相似,且各电磁波信号的初始脉冲均较大,其传播路径为直线路径。局部放电源靠近GIS外导体时,电磁波信号波形与检测位置φ相关,在φ=0和φ=180°处检测的信号中有大脉冲出现,其传播路径为沿GIS外壳内表面绕向传播路径。

Ultra-high frequency （UHF） method is widely used for partial discharge （PD） detection in gas insulated switchgear （GIS） for the advantages of high sensitivity, good ability of anti-disturbance and the accuracy of PD location. Currently, the research about the propagation characteristic of electromagnetic wave （EM-wave） of PD in GIS are emphasis on the EM-wave resonance and attenuation characteristic, while the EM-wave of PD propagation routes characteristic and the relationship between propagation routes with EM-wave signal wave havefft get attention. For investigating the EM-wave of PD propagation characteristic, firstly, the simulation model was constructed and analyzed with finite difference time domain （FDTD） method which used to studying the relationship between EM-wave signal and EM-wave propagation routes. Then, a manual PD source was constructed by putting a needle in actual GIS and the PD signals detected by UHF sensors were analyzed in this paper. The simulation and experiment results show that the EM wave propagation routes are related with the PD position. When PD source locates near the inner conductor of GIS, the EM-wave signal waves are similar which detected at different position 4 and the initial pulses of these signals are big which propagating in direct route in GIS. When PD source locates near the outer conductor of GIS, the EM-wave signal waves are different which detected at different position 4. But the initial pulses of EM- wave signals are small and there are big pulses appearing in the EM-wave signals which propagating around the inner surface of outer conductor when ∮=0 and ∮= 180°.