基于故障分量综合阻抗的母线保护新原理

Novel Busbar Protection Based on Fault Component Integrated Impedance

提出了基于故障分量综合阻抗的母线保护新原理。利用故障时母线上故障分量电压相量与母线上各支路故障分量电流相量和的比值,来判断母线的内、外部故障。在外部发生故障时,该比值反映母线的容抗,其模值很大;内部故障时,该比值反映母线上各支路阻抗的并联,其模值相对较小,据此可以区分内部、外部故障。新原理判据灵敏度高,具有一定的抗电流互感器饱和能力,简单、易整定,而且对于3/2断路器接线的母线内部故障时有电流流出的情况也具有较高的灵敏性和可靠性。EMTP仿真验证了新原理的有效性和可行性。

Based on the ratio between the fault component voltage phasor of the busbar and the sum of all branch current phasor of the busbar, whith is defined as the fault component integrated impedance, a novel busbar protection principle is proposed. When an external fault occurs, the fault component integrated impedance reflects the capacitance impedance of the bus, whose value is very large. When an internal fault occurs, the fault component integrated impedance reflects the paralleling result of all the lines＇ impedances, which are connected to the bus. Its value is relatively small. According to such a characteristic, whether there is a fault on the busbar can be determined. The criterion is insensitive to transition resistance, and can be applied in breaker-and-a-half busbar when an internal fault occurs and when there is current flowing out＇of the bus. In addition, it can be easily set. EMTP simulation results show that the proposed principle is highly effective and reliable.