Measurement of propagation velocity of the electromagnetic wave produced by partial discharge in a gas-insulated switchgear

This paper presents an effective technique for measuring the propagation velocity of the partial discharge (PD) electromagnetic (EM) in a gas-insulated switchgear. The propagation velocity varies with the type of gas insulated switchgear. Because of this, it is necessary to evaluate the propagation of a PD EM wave front between different points in the gas insulated switchgear. The signal time delay is determined by locating the initial PD in the cumulative energy plot, as obtained by the correlation of the signals from two UHF sensors. The efficiency of this method is illustrated with experimental results.