A study on effects of conducting particles in SF/sub 6/ gas and test methods for GIS

The effects of conducting particles in gas-insulated switchgear (GIS) on insulation performance were investigated. The objective was to recognise the relationship between the length of conducting particles and AC impulse flashover voltages. The data showed that the minimum harmful length of conducting particles at various voltages applied to GIS in service is governed by lightning surge amplitude corresponding to the basic impulse insulation level (BIL). The size of minimum harmful conducting particles was also estimated for various GIS ratings. To further improve the reliability of GIS, factory and on-site test methods are suggested for preventing insulation failures caused by conducting particles.<
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