Simulation on Motion Characteristics of Free Metal Particles in GIS / GIL under Power Frequency Voltage and Vibration Superposition

Free metal particles are an important cause of insulation failure to the gas-insulated switchgear (GIS) or the gas-insulated transmission lines (GIL), and there are few research reports that free metal particles in GIS/GIL may move and induce insulation breakdown, affected by the high voltage bus voltage and multiple frequency or occasional vibration. In this paper, a simulation model of metal particle movement in the 1100 kV GIS or GIL system is established. The charge, force and movement of free spherical metal particles under the power frequency voltage and mechanical vibration superposition was analyzed. The movement law of spherical metal particles under power frequency voltage was studied. And the influence of different vibration conditions on the movement of metal particles was obtained. Based on the movement law of metal particles, the collision momentum-flight time spectrum (CMFT) of metal particles under the superposition of power frequency voltage and vibration were extracted. The results of this study may provide a new idea for the detection and identification of free spherical metal particles in GIS/GIL. The results show that the threshold voltage of particle take-off is affected by the density and size of metal particles, the amplitude and frequency of vibration. The multiple frequency vibration amplitude can effectively increase the width of the CMFT, the maximum flight time and the maximum collision momentum. And the particle movement of materials with high collision recovery coefficients is more obvious and easier to detect. But occasional vibration has little effect on the movement of spherical metal particles. It can only affect the initial state of the particles and generate a few points to extend the spectrum.