Abstract：When there are metal particles in gas chamber of gas insulated switchgear (GIS), it is easy to cause electric field distortion and even insulation breakdown. In this paper, a case of single-phase ground fault of phase C circuit breaker in the process of closing and sending power of 220kV GIS circuit breaker is taken as an example, by using SF6 gas composition analysis, on-line monitoring of partial discharge, disassembly inspection, simulation test of metal particles under scaled model and bolt material analysis, the result shows that when there are metal particles inside the GIS gas chamber, the on-line monitoring partial discharge signal is much larger than the normal signal, but the frequency of the discharge signal is less, and the alarm conditions may not be achieved. The simulation test shows that when there are metal particles inside the GIS gas chamber, the internal insulation breakdown is more likely to occur when the GIS is subjected to vibration shock. The main reason for this failure is the discharge of internal metal particles under the influence of vibration shock and airflow during the start-up process.
2024, Vol. 25 
