Research of Partial Discharge Localization Method in GIS Based on UHF Technique

Abstract:- Some small defects like fix protrusion or free moving particles exist in GIS can induce partial discharge (PD) which will deteriorate insulation condition and eventually cause insulation breakdown when GIS are in service. It is very important to detect and locate the PD signal for early detection of insulation defects and preventing insulation failure. Time of flight method which based on Ultra High Frequency (UHF) technique is widely used for locating PD in GIS for the merits such as simple principle and easy implementation. But in application, the time of flight method can hardly be applied effectively and will induce errors if the initial pulse of the PD signal is small and blurry or its signal-to-noise ratio (SNR) is too low. In this paper, the characteristics of electromagnetic wave (EM-wave) propagation route in GIS were investigated and a new localization method was proposed. The simulation and experiment results show that the EM-wave signals induced by PD in GIS are related with EM-wave propagation routes, which were decided by the location of PD source and detector’s position. The experiment results show that the proposed PD localization method which based on the characteristics of EM-wave propagation route can locate the PD signal well and effectively in the case that the initial pulse of PD signals is very small and blurry when PD source locates near the outer conductor of GIS