Cause Analysis and Improvement of 550 kV GIS DS Ground Flashover
Through the analysis of the ground flashover accident during the opening process of 550 kV GIS disconnector switch (DS) based on the faulty DS disintegration research,EMTP numerical calculation and testing and on-site validation,it is found that the ground flashover accident occurs due to the heavy breakdown of fracture at 54 mm fracture location with small probability,and the consequent VFTO (very fast transient overvohage) exceeding the DS's insulation level to ground in this condition.Accordingly,the technical improvement scheme for the DS internal structure is proposed,which has been tested in factory and verified in the DS the capacitance current duty1 and duty3 test stipulated by IEC standards.The DS transformation has been completed on site.
gas insulated switchgear (GIS)disconnector switch(DS)ground flashover
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