电力系统低频振荡和次同步振荡统一模型阻尼分析

电力系统低频振荡和次同步振荡可能存在阻尼耦合，电力系统稳定器PSS(Power System Stabilizer)等控制装置的加入在抑制低频振荡的基础上，会引发系统次同步振荡。从系统阻尼出发，运用小干扰分析法．对低频振荡和次同步振荡实施统一建模，并分析系统的阻尼变化规律。对算例运用特征根分析法．分析比较了PSS、励磁放大倍数以及发电机出力和功率因数等参数变化对系统各振荡模式阻尼的影响。结果表明系统阻尼守恒，且低频振荡与次同步振荡不可共容；在调节以上参数时须考虑对低频振荡和次同步振荡的双重影响。

Damping analysis of unified LFO & SSO model in power system

The damping coupling between LFO(Low Frequency Oscillation) and SSO(SubSynchronous Oscillation) may occur in power system. The suppression of LFO by PSS(Power System Stabilizer) may cause SSO. With the consideration of system damping,a unified model is built for both LFO and SSO by using the small disturbance approach. The damping variety rule is analyzed as well. Ap,plying the eigenvalue approach to an example,the influences of PSS,excitation amplification,generator active power and power factor on damping of different oscillation modes are analyzed and compared. Results verify the conservation of system damping and the incompatibility of LFO and SSO. When regulating above parameters,their dual influences on LFO and SSO should be con,sidered.