Failure protection of Shengli Oilfield 220 kV substation main transformer circuit breaker, its typical configuration cannot effectively isolate the fault point, in some atypical failure,the main transformer for a long time by the impact of short-circuit current,seriously affect the power system stability and safety. The failure protection action nodes and mother difference protection action nodes and the corresponding non electric starter relay series, when startup failure protection, the corresponding node closed, start relay, to direct trip-ping of main transformer with three side of the switch. Using this improved scheme, 3 of Shengli Oilfield 220 kV substation main transformer failure protection has been improved, reduces the possibility of 220 kV Main Transformer be impact by the fault current, guarantee the safe and stable operation of power grids.%胜利油田220 kV变电站主变断路器失灵保护中的典型配置不能有效隔离故障点,在一些非典型故障中,会使主变长时间受到短路电流冲击,严重影响电力系统稳定性和安全性.为此,将失灵保护动作节点和母差保护动作节点与相应的非电量启动继电器串联,当失灵保护启动时,相应节点闭合,启动继电器,进而直接跳开主变三侧开关.应用此改进方案,对胜利油田3座220 kV变电站的主变失灵保护进行了完善,降低了220 kV主变压器受到故障电流冲击的可能性,保障了电网安全、稳定运行.
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