特高压GIS局部放电超声波传播特性仿真

To understand the propagation characteristics of ultrasonic signal brought about by partial discharge in GIS, the finite element method is adopted to simulate the ultrasonic signal propagation characteristics of the partial discharge in different locations of ultra-high voltage (UHV) GIS. A three-dimensional UHV GIS simulation model is established, and the monopole sound source is set at the surface of the GIS center conductor and the spacer respectively. Multiple ultrasonic sensors are arranged at different positions of the GIS enclosure to receive the ultrasonic signal generated by partial discharge. The ultrasonic sound pressure distribution on GIS wall, which is generated by different monopole sound sources, is obtained via simulation, and the characteristics of the ultrasonic signal in time-frequency domain are also obtained. The game process of different paths of the ultrasonic signal is discussed. By analyzing the time sequence of the received ultrasonic signals from different monopole sources, the ultrasonic signal transmission paths versus different source locations are determined. Simulation results show that: 1) when the monopole sound source is located in the center conductor remote from the spacer, the ultrasonic signal first reaches GIS enclosure with the shortest distance between the monopole sound source and GIS enclosure, then spreads to both sides; 2) when the monopole sound source is located on the spacer or the center conductor near the spacer, the ultrasonic signal spreads along the spacer to GIS enclosure and then spreads to both sides; 3) the ultrasonic spectra received by the sensors almost concentrates in the range of 30~40 kHz, while the ultrasonic signals attenuate quickly in higher frequency range of 60~80 kHz; and 4) the attenuation process of the ultrasonic signals follows exponential function when the sensor keeps away from the source, and the signals attenuate more seriously when they propagates across the spacer.