206 / 2021-11-01 08:46:19

Study on PT secondary interference of 1000kV GIS substation based on SWT transformation

gas insulated substation (GIS);,very fast transient overvoltage (VFTO);,synchronous compression wavelet transform (SWT);,time-frequency characteristics

Power system and automation > Modeling, control and stability analysis in power system

Abstract——In order to explore the interference characteristics of Very Fast Transient Overvoltage (VFTO) on secondary equipment, this paper uses a self-made secondary side interference measurement device to measure the voltage of a 1000kV Gas Insulated Substation (GIS). The common mode interference on the secondary side of the Potential Transformer (PT) was measured on site. In this paper, the synchronous compression wavelet transform is used for time-frequency analysis of the measured waveform. The actual measurement results in this paper show that the peak-to-peak common-mode interference voltage on the secondary side of the PT can reach 9.65kV, and the maximum frequency of micro-pulses is about 1kHz. The Fourier analysis of micro-pulse shows that the greater the amplitude of the interference pulse on the secondary side of the PT, the more abundant the frequency. The time-frequency analysis results of the micro-pulse show that the 7.8MHz frequency component has a high amplitude and the dominant frequency component of the PT secondary side interference is always throughout the waveform. The amplitude of other frequency components begins to decay rapidly after the waveform occurs, and the duration is different.

Corresponding author's information：Ji Jianfei is State Grid Jiangsu Electric Power Co., Ltd. Electric Power Research Institute, Nanjing 210000, China (Email: astepaway@foxmail.com)