一种改善距离保护动作特性的方法及其应用

Improving Method of Action Characteristics of Distance Protection and Its Application

以正序电压极化为原理的方向阻抗继电器,广泛运用于线路距离保护中;然而由于原理及处理过程复杂,动作性能有缺陷。文中分析了其工作原理及缺陷,提出了一种改进型方案,即采用复合电压极化的方向阻抗继电器,并对距离保护的各元件作了优化,改善了动作特性,特别是出口处正反方向对称故障的动作特性。通过理论分析试验对比,提高了动作正确率及出口时间。基于此开发了一套线路66 kV线路距离保护测控装置,通过了数动模试验,并在现场投入运行,显著改善了运行性能。

The directional impedance relay （Mho relay） based on positive sequence polarizing voltage theory is applied widely to the power line distance protection. However, due to the complexity of its theory and process, its action performance has defects. Based on the analysis of working principles and the defects, a reform scheme is proposed. The directional impedance relay using composite polarizing voltage is adopted and the distance protection components is optimized, improving the action performance of the directional impedance relay, esperationally when the balanced fault in positive and negative directions takes place at the outlet. Based on tests and theoretical analysis, it is found that the correctness and the action time are improved compared with ever. Then a set of measurement and control device is developed for the distance protection of 66kV line. The device is so successful in digital-analog and dynamic simulation tests that has been put into real practice. It improves the performance of the distance protection markedly.