水轮发电机组励磁误强励故障的分析及处理

Analysis and Treatment of Faulty Forced Excitation of Hydro-turbine Generator Units

针对某大型水电站机组励磁系统在安装调试过程中出现的两次误强励事件,经对误强励事件产生的过程和原因进行理论分析表明,这种误强励情况的发生是由于励磁程序角度计算子程序没有采用跟频算法造成的。当考虑机组正常并网运行时频率不会发生大幅变化,角度计算程序采用常量较采用变量可靠性高。而当机组在空载状态下进行甩负荷和停机时频率会出现大幅变化时,跟踪固定频率算法已不能满足实际工况要求,而应改为采用智能跟频的算法,并提出了预防措施。

In the installation and commissioning of the unit excitation system in a large-scale hydropower station,two faulty forced excitation events occurred.Analysis on the process and causes of the events shows that the faults occur because the angle calculation subroutine in the excitation program does not adopt the frequency tracking algorithm.When the unit is in its normal grid connected operation,the frequency will not change significantly.Thus,the angle calculation subroutine with constant frequency is more reliable than that with variable frequency.However,when the unit is in the no-load condition for load shedding or shutdown,the frequency will change greatly.The constant frequency algorithm is no longer suitable for the actual working condition.In this case,the intelligent frequency tracking algorithm should be adopted instead.Then,some prevention measures are proposed.