针对铜川电厂1号机组主变高压侧B相接地故障中，主变差动保护动作后，发电机记忆过流保护仍动作跳母联的事故，详细分析了发电机记忆过流保护的动作行为，对增加发电机并网状态和取消跳母联出口方式这2种事故处理措施进行了说明。结合当前大机组继电保护的发展，进一步讨论了发电机后备保护配置问题，提出简化发电机后备保护的建议。

In No.1 unit of Tongchuan power plant, the bus coupler breaker tripping accident occurs which is caused by memory over-current protection malfunction of generator after main transformer differential protection acts in B phase ground fault of HV side of main transformer. The principles of memory over-current protection of generator are analyzed in detail. In addition, the treatment of accidents is put forward including increase of generator interconnection and cancellation of bus coupler breaker tripping. Combining with the development of relay protection for large units, the backup protection of generator is discussed, for simplifying which the corresponding suggestions are provided.