The equivalence of weighted IMF partial discharge signals pulse injection by different coupling modes in GIS

Abstract

Pulse injection to simulate partial discharge (PD) is the main method for functional verification of gas insulated switchgear (GIS) ultra high frequency (UHF) PD monitoring device. Due to the different coupling modes of pulse injection in field verification, the equivalence law between simulated PD and actual PD is not clear, and the effectiveness of functional verification of monitoring device cannot be guaranteed. In this paper, a typical PD defect (tip, suspension, insulator bubble) and internal/external pulse injection UHF PD detection platform for 126 kV GIS are established, and the effective pulses of UHF signals are normalized and extracted. Then a signal processing method of weighted intrinsic mode functions (IMF) based on empirical mode decomposition is proposed. The signal equivalence is characterized by calculating the average and maximum values of the Euclidean distance of the signal, and finally compared with the conventional signal deviation method. The research shows that compared with the conventional signal equivalence analysis method, the weighted IMF method can effectively solve the problem of large local difference of UHF signal waveform. The internal sensor pulse injection analog PD and suspended PD have the highest equivalence. The average value Me and the maximum value Ma of Euclidean distance are 3.82% and 10.28%, respectively. Therefore, the function verification of UHF monitoring device can use constant parameter pulse injection instead of suspension defect, and the internal UHF sensor injection can be preferred for analog PD. The research in this paper can provide reference for the pulse injection method for the function verification of UHF PD monitoring device.

Keywords

• pulse injection
• partial discharge simulation
• empirical mode decomposition
• signal equivalence analysis
• intrinsic mode functions (imf)
• euclidean distance