水轮机组正常停机时差动保护误动作分析

Analysis on Inaccurate Action of Differential Protection During Normal Shutdown of Hydraulic Turbine Units

根据现场一起水轮机正常停机时发电机差动保护误动作事件,对电气制动闭锁发电机及发变组差动保护进行分析,并通过现场试验证明导致发电机差动保护误动作的原因是电气制动开入量的可靠性差,并非保护误跳闸。

Based on a case of inaccurate action of differential protection during normal shutdown of a hydraulic turbine unit in the Fengman Hydropower Plant, the electric power braked generator and the differential protection of the generator-transformer unit are analyzed. The cause of inaccurate action of the generator＇s differential protection is found out through field tests, that is the low reliability of the electric braking capacity, not the inaccurate tripping of the protection.