电力系统稳定器抑制次同步谐振的效果

Effect of Exciter and Power System Stabilizer on Subsynchronous Resonance Damping

采用时域仿真实现的复转矩系数法——测试信号法,基于IEEE次同步谐振第一标准测试系统及IEEE ST1A型励磁系统,研究了电力系统稳定器(PSS)对次同步谐振的抑制效果。根据励磁系统的相位滞后特性,对PSS的相位补偿环节进行设计,利用多个串联的超前滞后环节补偿低频段及次同步频段的相位,从而实现缓解次同步谐振的目的。通过频率扫描计算出发电机组在次同步频率范围内的电气阻尼特性曲线,进而分析所设计的PSS对电气阻尼特性的影响,并分析了PSS放大倍数、相位补偿环节对阻尼特性的影响。此外,采用并联结构的PSS,对低频段和次同步频段的相位分别进行补偿,并研究此结构对电气阻尼特性的影响。结果表明,文中设计的这两种结构的PSS,均能大大减小系统谐振点附近的电气负阻尼,说明通过对励磁系统在次同步频段的相位滞后进行补偿,可以使PSS在提高低频振荡稳定性的同时,实现缓解次同步谐振的目的。

The effects of the power system stabilizer （PSS） on subsynchronous resonance （SSR） damping are studied in this paper based on the IEEE SSR first benchmark model and the IEEE ST1A type excitation system by means of complex torque coefficient approach, namely the test signal method, realized by time domain simulation. The phase compensation block of the PSS are designed to compensate the phase lags in the low frequency range and the subsynchronous frequency range, which result from the excitation system. Then the frequency scanning in the subsynchronous frequency range is performed to calculate the subsynchronous electrical damping characteristics of the unit and the impacts of the designed PSS on the electrical damPing are analyzed. And the effects of the parameters of the PSS such as the gain and the phase compensation block are also studied. Furthermore, the effects of a PSS with a parallel configuration on SSR damping are analyzed. The results show that with the two designed PSS the electrical negative damping around the resonant point are both reduced. It means that the PSS with the appropriate phase compensation can not only enhance damping of power system oscillations, but also mitigate the SSR simultaneously.