110kV线路接地距离Ⅲ段整定原则的探讨

Research of setting method of ground distance zone-Ⅲ protection for 110kV transmission line

通过一起110kV线路接地距离Ⅲ段保护在线路末端变压器35kV侧母线故障时越级误动事件的分析,提出接地距离Ⅲ段保护定值及时限在整定上的改进措施。使110kV线路接地距离Ⅲ段保护定值和时限与相间距离Ⅲ段保护的定值及时限按照相同原则整定。既可以提高远后备灵敏度,同时加强了远后备对相邻电力设备安全性的保障。

Based on analysis of mal-operation of ground distance zone-Ⅲ protection for 110kV transmission line which is caused by fault phase-to-phase occurred on 35kV busbar of transformer. An improved setting method for ground distance zone-Ⅲ protection is introduced in this paper. In order to improve the sensitivity and reliability of far back-up protection, setting values and operating time adopted in ground distance zone-Ⅲ protection should be equal to those in phase-to-phase distance zone-Ⅲ protection. This project is supported by National Natural Science Foundation of China（No.50607006）.