Study on the Propagation Characteristics of Partial Discharge Electromagnetic Waves in Gas Insulated Line

Abstract

Defects in the gas insulated line can cause partial discharge, and the electromagnetic wave is generated. The finite difference time domain method is used to research the propagation of electromagnetic wave in gas insulated line structures. The electric field strength of time-domain waveform is selected as characteristic factor for analysis. By changing the gas insulated line model, the attenuation of electromagnetic wave through double insulator, L-type corner, T-type corner, straight tube and different GIL sizes is studied. In the straight tube structure, the amplitude attenuation of electromagnetic wave is linear and the attenuation band is between 1 GHz and 1.7 GHz. In the insulator, basin insulator has more serious influence on signal isolation than disc insulator. After passing through the insulator, the signal attenuation is obvious in the frequency band above 1 GHz. The amplitude of electromagnetic wave decreases more seriously through the corner structure, and the attenuation is at the whole frequency band. In different sizes of gas insulated line, the larger diameters of shell and conductor, the larger electromagnetic wave will be, and the faster attenuation will be; the length of gas insulated line cavity has little effect on electromagnetic wave. The theoretical research is expected to help to arrange the position of ultra-high frequency sensor reasonably.