鸭河口电厂中压主汽门故障关闭分析及处理

Analysis and corrective action for reheat stop valve closing by fault in Yahekou Power Plant

针对近年来鸭河口电厂汽轮机中压抗燃油调节系统多次发生中压主汽门故障关闭,导致机组跳闸或甩负荷,影响中压主汽门全行程试验的正常进行,威胁机组安全运行的问题,通过分析中压主汽门故障现象、故障过程中系统安全油压的变化及原因、安全油压波动对中压主汽门板阀位置的影响、中压主汽门全行程试验程序及两侧中压主汽门进油阻力差异,发现全行程试验时电磁阀动作顺序错误,指出中压主汽门开启瞬间导致安全油压突降、并引起板阀移位是故障发生的根本原因。经改变电磁阀动作顺序、减小中压主汽门进油量和增强系统油压调节能力,解决了中压主汽门故障关闭的问题。

The reheat stop valve fault closing took place in the fire resistant control system in Yahekou Power Plant for several times. The consequent turbo-unit trip and load rejection would affect the full-travel test of reheat stop valve and even threaten the security of unit operation. Based on analysis for the variation of system safety oil pressure, the effect of oil pressure fluctuation on plate valve displacement, the program of full-travel test and the oil feed resistance difference of both side, the action sequence of magnetic valve during full-travel test was found to be incorrect. Root cause of the fault lies in safety oil pressure sagging and the following valve plate displacement during the instantaneous opening of stop valve. The fault closing problem can be solved by changing the magnetic valve action sequence, reducing the feeding oil of reheat stop valve and improving the control performance of system oil pressure.