原动机调速系统参数对低频振荡的影响

Influence on Low Frequency Oscillation by Parameters of Speed Governing System of Prime Mover

应用MATLAB建立原动机调速系统和电力系统相互作用的机网耦合模型,分析机网耦合是否能引发电力系统低频振荡。仿真分析表明,如果水轮机调速系统微分增益偏大且水轮机输出功率对水头的偏导数随负荷变化时,在扰动下可能出现功率的低频振荡。对于汽轮机调速系统,在系统的阻尼不太强时,汽轮机控制器参数对小信号系统稳定性具有重要影响。采用比例积分微分(proportional-integral-derivative,PID)控制器时,系统在小干扰下振荡衰减;采用PI控制器时,系统小干扰下出现幅值增大的低频振荡。

MATLAB software is used to set up agenerating unit and grid coupling model for interaction of speed governing system of prime mover and power system,and this paper analyzes whether generating unit grid coupling will cause low frequency oscillation of the power system.Simulation analysis indicates that if derivative gain of the speed governing system of hydraulic turbine is high and partial derivative of output power of the hydraulic turbine on the waterhead changes with load,low frequency oscillation of power may occur due to disturbance.With regard to speed governing system of the steam turbine,when damping of the system is not strong,parameters of the controller of steam turbine may have great influence on the small signal system.When using proportion integral differential（PID）controller,oscillation will decay under small disturbance,while using PI controller,low frequency oscillation with increasing amplitude may occur under small disturbance of the system.