Lightning or arc grounding overvoltage often cause damage on components in high voltage power distribution cabinet or even explosion , which is the main cause of equipment damage in substation. Once the failure occurs, it will result in widespread and long-time blackout. Current protection modes of arc suppres-sion and lightning protection measures are improved by searching for failure reason of arc suppression cabinet and analyzing the principle of arc suppression. After installing zero-sequence current transformer on substation incoming cable, it can be determined whether arc grounding happens inside or outside the substation depend-ing on the direction of zero-sequence current in case of single-phase arc grounding. For arc grounding over-voltage inside the substation, arc suppression controls are adopted; for that outside the substation, alarming measures are employed. Thus, the unnecessary arc suppression control as well as the metal grounding times of system caused by arc suppression control can be reduced.%雷电或弧光接地过电压往往造成高压配电柜内元器件损坏、甚至爆炸，是变/配电所设备损坏的主要原因，一旦故障发生，会造成大面积和长时间停电。通过故障消弧柜的故障原因查找和消弧保护原理分析，对现有消弧保护方式和避雷措施进行改进。在变/配电所进线电缆处安装零序电流互感器，发生单相弧光接地时，根据零序电流方向判断弧光接地发生在所外还是所内，对所内弧光接地过电压采取消弧控制，所外弧光接地过电压时仅报警，从而减少不必要的消弧控制和因消弧控制而导致系统金属性接地的次数。
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