汽动给水泵故障减负荷后高压加热器退出系统异常现象分析

Investigation into Abnormality of High Pressure Heater Tripping after Runback of Steam-driven Feedwater Pump

某电厂的发电机组给水泵故障快速减负荷(runback,RB)试验中屡次出现高压加热器(以下简称高加)水位波动,造成高加水位高保护动作,导致机组跳闸的事故。为此,针对给水泵出力和高加水位异常现象进行了具体分析,指出控制策略中燃料的瞬间过度减少是出现异常现象的主要原因,并提出了改进措施:减少跳磨煤机的数量;把汽轮机压力主控制调整成过阻尼模式的特性,改变衰减振荡的模式。

The runback（RB） test on feedwater pump of generating unit in some power plant failed repeatedly due to the water level fluctuation of high pressure（HP） heater,the ensuing operation of protection against high water level of HP heater and the tripping of the unit.Upon thorough investigation into the abnormalities of feedpump output and HP heater water level,the instantaneous sharp decrease of fuel in the control strategy is deemed to be the main causation of the abnormalities.Improving measures are proposed,i.e.decreasing the number of mills to be tripped,adjusting the main pressure control of steam turbine as overdamping mode and changing the mode of damped oscillation.