高中压缸联合启动机组切阀过程转速波动原因与处理

Cause Analysis and Treatment on Speed Fluctuation during Valve Switching of a HP-IP Cylinder United Startup Unit

针对某电厂300MW亚临界机组某次启动阶段,机组转速2 950r/min时TV-GV切换过程中汽轮机转速波动导致切阀时间过长的现象,通过分析高中压缸联合启动转速和切阀控制逻辑,结合切阀动态过程和相关冲转参数,得出再热压力的波动是转速波动的直接原因,提出了在切阀过程中通过调整高、低压旁路阀门开度,保持再热压力稳定的有效方法来防止转速的异常波动和缩短切阀时间,对同类型发电机组启动调试及运行有一定的指导意义。

According to the too long valve switching time caused by speed fluctuation of the turbine during TV-GV switching process of a 300 MW subcritical unit when the unit was operated at 2 950 r/min in start-up period, and by analyzing the combined startup speed of the HP-IP cylinder and the valve switching control logic, in combination with the dynamic process of valve switching and relevant rolling-up parameters, the problem was found to be caused by reheat pressure fluctuation. It is proposed to prevent abnormal speed fluctuation and shorten the time of valve switching by adjusting the opening of both high and low pressure bypass valves, so as to keep reheat pressure stable in the process of valve switching. This may serve as a reference for startup, commissioning and operation of similar power generation units.