基于序电流比值关系的高压输电线路断线故障判别与保护方法

Identification and protection method of disconnection fault based on sequence current ratio for high voltage transmission lines

针对目前高压输电线路继电保护装置无法有效识别断线故障的问题,本文详细讨论了输电线路发生断线故障后距离保护和零序电流保护的动作逻辑,利用对称相量法分析出断线故障后的电流、电压以及序电流的变化特征。提出以断线故障后正序电流与零序电流的比值关系为基础,结合故障后电流、电压的特征,适合不同电压等级的输电线路断线故障识别判据,完善距离保护和零序电流保护针对断线故障的保护逻辑。最后,通过在四川省川丹巴线和川小金线的不同电压等级的输电线路上进行测试和分析,验证了本文所提断线故障判别及保护方法的可行性和有效性。

Aiming at the current problem that the relay protection device of high voltage transmission lines cannot identify the disconnection fault effectively,this paper discusses the operation logic of distance protection and zero sequence current protection after the disconnection fault occurs in transmission lines in detail,and analyzes the variation characteristics of current,voltage and sequence current after the disconnection fault by using symmetric phasor method.This paper puts forward the identification criteria of transmission lines disconnection fault suitable for different voltage levels,and perfects the protection logic of distance protection and zero sequence current protection against the disconnection fault.This criterion is based on the ratio relationship between positive sequence current and zero sequence current after disconnection fault,and combines the characteristics of current and voltage after fault.Finally,the feasibility and effectiveness of the fault identification and protection method proposed in this paper are verified by testing and analysis on the transmission lines with different voltage grades of Chuandanba line and Chuanxiaojin line in Sichuan province.