汽机调门重叠度非线性引发有功功率振荡原因分析

针对机组运行过程中出现的发电机有功功率异常波动导致电网低频振荡现象进行了现场试验。通过在现场试验中再现发电机有功功率振荡现象,对机组参与一次调频过程中汽轮机阀门在不同运行区域对发电机有功输出的影响进行分析,发现引起发电机有功低频振荡的原因为汽轮机调门配汽方式不当造成了调门重叠度的呈非线性。调整调门配汽运行区域后发电机有功功率异常波动现象消除。提出了调门优化以提高重叠度线性度、负荷闭环控制方式退出、汽轮机调门工作区域与重叠度非线性区错开等防止发电机有功功率振荡的应对措施。

Analysis of Active Power Oscillation Caused by the Nonlinearity of Steam Turbine Valve Overlap

The low frequency oscillation caused by the abnormal generator active power fluctuation during the operation of generator is tested in field. By reproducing the generator active power oscillation phenomenon in the field test, and analyzing the influence of the turbine valve in different operation region to the generator active power output during the generator primary frequency regulation process, it is found that the incorrect stream distribution mode of steam turbine valve which causes the nonlinearity of stream turbine valve is the reason of generator active power low frequency oscillation. The abnormal fluctuation disappeared after the regulation of the operation region of the valve stream distribution. Countermeasures to prevent the generator active power oscillation are proposed including the optimization of valve to improve the linearity of the overlap, the quit of the load close loop control mode, and the dislocation of the working region of steam turbine valve and the nonhnear overlap region.