N600错误接线导致工频变化量保护误动作的分析

Analysis of Protection Misoperation of Power-frequency Variation Caused by Error Connection of N600

通过对两套母差保护装置动作报文及SF6气体绝缘组合电器(GIS)#5气室分解物进行分析,初步确定220kV侧正母线发生接地短路故障。对工频变化量保护原理进行分析,得出母线发生接地故障不是引起线路工频变化量保护动作的原因。经过进一步分析故障线路录波文件,发现其故障电压特征存在异常现象。现场查看故障线路电压回路,发现在220kV电压分屏线路III间隔N600错接在电压互感器开口三角UL端子上,3U0在母线发生接地故障时急剧增大,从而导致工频变化量保护判决条件满足而误动作。

Based on two sets of Busbar protection device message and SF 6 gas-insulated switchgear （GIS） #5 air chamber decomposition analysis, preliminary determined 220kV side is Busbar earth fault.The principle of protection for power-frequency variation is analyzed, concluded that the earth fault of bus bar did not cause the protection of power-frequency variation operation. Further analysis fault wave record file, found that its voltage existing anomaly. By checking the fault line voltage loop, found the N600 of the line protection device error connected on the U L terminals of open delta voltage on transformer in the voltage of subsection cabinets. When bus bar ground fault occurs, 3U0 increases sharply, leading to the misoperation on the protection decision of power-frequency variation.