微粒缺陷引发220 kV GIS绝缘击穿的事故分析及预防措施OA

GIS is one of critical equipment of power system and its safe and reliable operation is very important.The insulation breakdown in cable compartment of 220 kV GIS in a power plant is analyzed.It is concluded by the judgement of the fault recording diagram that single⁃phase grounding short circuit occurs firstly,followed by the three⁃phase short circuit.Based on the disintegration and detection,the accident process is analyzed as follows:dur⁃ing operation,foreign particle drops in the gas compartment and enters into the strong electric field area of the cable compartment,leading to electric field distribution and single⁃phase breakdown.Since no insulating barrier is set be⁃tween the cable compartment and the gas compartment of disconnector,the molten metal splashes onto the support spacer of the earthing switch after a single⁃phase breakdown,leading to the escalation of the accident and resulting in a three⁃phase short circuit.Drawing lessons from the accident,such preventive measures as selecting stainless steel adsorbent box,reasonably reserving insulation margin of non⁃standard parts in GIS,strengthening patrolinspec⁃tion and assessment of equipment status are proposed so to provide practical basis for safe operation and design opti⁃mization of GIS in the future.