母线差动保护中母联电流互感器布置分析及保护逻辑改进

Analysis on Arrangement of Bus Tie Current Transformers and Improvement of Protection Logic in Bus Differential Protection

在双母线接线方式的工程设计中,对于接入母线差动保护的母联电流互感器,通常有两种完全不同的布置方案。第一种是两组母联电流互感器全部布置在母联断路器一侧,第二种是两组母联电流互感器对称布置于母联断路器两侧。分析了两种母联电流互感器布置方案对母线差动保护的影响,确认死区或交叉区域位置发生故障都会引起双母线断开。在第二种布置方案的基础上,采用两组母联电流互感器的差流作为冗余判据,进而决定保护逻辑,有效避免两条母线均被断开的问题。

In the engineering design of the double bus connection method,there are usually two completely different arrangement schemes for the bus tie current transformer connected to the bus differential protection.The first scheme is that the two sets of bus tie current transformers are all arranged on one side of the bus tie circuit breaker,and the second scheme is that the two sets of bus tie current transformers are symmetrically arranged on both sides of the bus tie circuit breaker.The influence of two arrangement schemes of bus tie current transformers on bus differential protection was analyzed.It is confirmed that a fault in the dead zone or cross-region will cause the double bus to be disconnected.On the basis of the second arrangement scheme,the differential current of two sets of bus tie current transformers is used as the redundancy criterion,and then the protection logic is determined to effectively avoid the problem of both buses being disconnected.