快速隔离母联死区故障的母线保护

Bus Protection for Fast Isolation of the Bus Tie Dead Zone Faults

针对双母线接线的母差保护,在母联死区发生故障时,因无法自动识别母线运行状态,导致故障跳闸缺乏选择性且实际故障母线切除时间长的问题,提出一种快速隔离母联死区故障的母线保护原理。新原理将母联断路器两侧CT同时接入母线保护,通过增加母联间隔比率差动,调整小差差流计算方法,使得故障时母线保护装置可自动识别母联断路器分合状态,并准确辨识故障位置,从而提高母联死区保护故障时故障切除的快速性和选择性。仿真结果表明:该方法实现了故障切除的快速性或最小范围隔离故障,提高了母线设备运行状态的自动化以及母线保护装置的智能化水平。

For the bus differential protection with double bus connection,when the bus coupler dead zone fault occurs,the bus operation status cannot be automatically identified,which leads to the lack of selectivity of fault trip and lengthened time of removal of the actual fault bus. This paper presents a bus protection principle for fast isolation of the bus tie dead zone fault. In the new principle,the CTs on both sides of the bus coupler circuit-breaker are connected to bus protection at the same time. By increasing bus bar interval ratio differential and adjusting the small differential current calculation method,the bus protection device is made to be able to automatically identify the opening and closing state of the bus coupler circuit breaker and accurately identify the fault location. Therefore,the rapidity and selectivity of the fault removal can be improved when the bus tie dead zone protection fails. The simulation results verify the effectiveness of the scheme.