The study of partial discharge in GIS under impulse voltage based on time-frequency analysis

In order to explore the mechanism of partial discharge (PD) in SF
₆
, a artificial suspension defect was installed in the bus segment of 220kV GIS and the PD in GIS under impulse voltage was detected. In this paper, the time frequency analysis theory i.e., short-time Fourier transform (STFT), Wigner-Ville distribution and Gabor Transform (GT), was applied to study PD signals. The results indicated that the signals, which were processed by STFT, Wigner-Ville distribution and GT, could correctly reflect characteristic of the PD pulse sequence in time-frequency plane and the variation patterns of the single pulse frequency spectrum with the change of time. It was easier to get the gathering area of the PD pulse sequence in the time-frequency plane by STFT and GT than Wigner-Ville distribution.