Investigation of states recognition of motion conducting particles under DC voltages using the pulse current method

Gas insulated switchgear (GIS) is widely used in the power system, due to its high reliability and great insulation characteristics. However, partial discharge (PD) caused by particle contamination in GIS threatens the stability and reliability of power system. Experiments have been carried out to observe the motion trials of single macroscopic conducting particle under DC voltages. Simultaneously, the pulse current signals have been measured. The result shows that the dominant frequency of PD signals for conducting particle under DC voltage is in the range of 0~7 MHz. In this paper, a method that recognized the particle states is proposed based on pulse characteristic parameter maps which consist of time intervals between pulses (Δt), discharge numbers (n) and discharge charges (q). The result indicates that pulse characteristic parameter maps can be used to recognize the motion states of metallic particle.