变配电站越级跳闸与速断保护设置问题分析

分析了一路主供,一路备用,单母线分段的10 kV变配电站,在主供电源与备用电源短路电流相差比较大时,备用电源投入后,出线断路器出口发生短路事故时,容易发生越级跳闸造成全站停电.提出:根据主供与备用电源运行方式,分别设置各自不同的速断保护整定值,采用微机保护,自动选择需要投入的保护整定值,以防止发生越级跳闸.

Analysis of Override Trip and Instantaneous Trip Protection Setting for Substation

A 10kV substation with one loop as the main power supply,one loop as the standby power supply and with single bus in section is studied. When the difference of short-circuit current between the main power supply and the standby power supply is large,the standby power supply is switched on and short-circuit accidents are occurred at the exit of the outlet circuit breakers,override trip is easy to happen and it causes the power failure of the whole station. It is suggested that setting values of instantaneous trip protection are set based on the operation mode of main power supply and standby power supply. In order to prevent override trip from happening,microcomputer protection is be adopted to automatically select setting values.