某水电厂3号机组失控故障分析与处理

Analysis and treatment of out-of-control failure of Unit 3 for a hydropower plant

某水电站机组在并网时突然不受控且逐步溜负荷,正常停机流程失效,自动与手动投入紧急停机阀,机组甩负荷导叶却未立即关闭,造成机组过速事件。通过对该机组调速系统及液压系统控制流程原理及一系列试验检查分析,判定故障的原因为紧急停机阀卡涩。更换紧急停机阀后,故障消失。并针对该故障暴露的机组故障控制系统机制不完善问题,提出相关改进意见。

The unit 3 of a hydropower plant was suddenly out of control and gradually slipped load when it is connected to the grid.The normal shutdown process failed.The emergency stop valve was automatically and manually turned on.The wicket gates failed to close immediately in case of load rejection,which resulted in over-speed of unit.Through a discussion on the principle of the control process of unit speed control system and hydraulic system as well as a series of test inspections,it is concluded that the cause for the failure is emergency stop valve jam.After replacing the emergency stop valve,the fault disappeared.Relevant improvement suggestions were put forward in view of the imperfect mechanism of the unit’s fault control system exposed by this failure.