弱电侧选相元件的探讨

Discussion for fault phase selector on the weak-feedback side of transmission line

相电流差突变量选相元件和电流序分量选相元件在数字式高压线路保护中得到了广泛的应用,但在弱电源系统中存在电流量自身无法克服的困难而不能正确工作。该文利用某电网一端为弱电源的220kV线路发生单相故障的录波数据,通过仿真计算,分析比较了3种电流突变量选相元件的性能,同时分析了目前弱电源识别方法存在的问题。在理论分析和仿真计算的基础上,提出了有效识别弱电系统的方法,并给出了弱电侧选相问题的解决方案。

Although phase selectors of current-difference sudden-change component and current sequence component have been applied in digital HV transmission line protective system, they can′t work correctly in weak-feedback system owing to their own defects. Making use of simulating calculation with record data of one ground fault in a 220 kV weak-feedback system, this paper compares the performances of three fault component phase selectors, analyzes the problems that exist in identifying weak-feedback system at present. Based on theoretical analysis and simulating calculation, efficient method is presented to identify the weak-feedback system, and a scheme is put forward to resolve fault phase selection in these systems.