手跳线路分相断路器失灵时预防事故扩大的方法

Method of Prevention from Expansion of Phase-segregated Circuit Breaker Malfunction in Manual Tripping

现场出现了几起手跳分相断路器时一相或两相断路器失灵的情况,但目前的规范并未要求手跳断路器失灵时启动失灵保护,若由零序过流保护动作切除负荷电流,可能导致事故扩大。目前南网220 kV线路保护通过修改软件实现了三相不一致和单相运行三跳动作后远跳线路对侧,但国网以及南网有些地区的保护不具备软件升级条件,提出了将手跳继电器触点和断路器三相位置不一致状态触点串联后接入纵联电流差动保护的其他保护动作开入方法。该方法简单可靠,便于实施。

There have been reported several on-site instances of one-or two-phase circuit breaker malfunction during manual tripping of phase-segregated circuit breakers,but the current regulations do not require to activate protection against manual tripping circuit breaker malfunction.Hence if under this situation the load current is cut off by zero-sequence overcurrent protection,the accident may expand.At present the protection of 220 kV lines in Southern Power Grid has achieved remote tripping to line′s opposite side after three-phase inconsistency and single-phase operation with three tripping actions through software modification.However,some areas of State Grid and Southern Power Grid do not have the conditions for software upgrade for protection.A method has been proposed working by connecting the manual tripping relay contacts and the three-phase position inconsistency state contacts of the circuit breaker in series and connecting them to other protection actions of longitudinal current differential protection.This method is simple,reliable,and easy to implement.