线路近区反向故障时保护误动分析及对策

Analysis and countermeasures of protection device wrong action for line close-in area reverse fault

电源侧中性点接地而负荷侧中性点不接地的110kV系统接线方式下,若重负荷110kV线路在运行中发生近区反向单相接地故障,由于闭锁元件设计考虑不周会导致距离保护误动跳闸。本文通过对220kV正谊变117谊旌线保护装置误动情况进行理论分析和实际故障数据计算,提出了采用零序电流元件和负序方向元件把关的解决对策,保证了微机距离保护装置在区内外故障时动作行为的正确性。

Under 110kV system wiring mode of power supply side neutral point grounding but load side neutral point unearthed, if occurs the close-in area reverse single phase grounding fault in 110kV heavy load line operation, due to the design problem of blocking element lead to the wrong action of distance protection trip. Through the theoretical analyzing and practical fault data calculation for the wrong action of 117 Yijing line protection device in 220kV Zhengyi substation, puts forward solutions of using zero sequence current element and negative sequence direction element, guarantees the action correctness when processor distance protection device in area fault and out of area fault.