电力系统稳定器(PSS)是抑制低频振荡最常用的方法，但安装了基于负阻尼机理设计的PSS后仍然可能发生共振机理低频振荡。推导了共振机理低频振荡幅值的数学表达式，并对振荡模式的共振特性进行分析。据此提出了抑制共振机理低频振荡的PSS设计方法。本方法设计的目标函数不仅考虑PSS的相位补偿特性，同时考虑了其幅频特性，能够更好地补偿振荡频率处所需相位并调整PSS提供的增益。此外根据不同振荡模式的共振特性计算得到不同的权重系数，保证了对系统危害更大的振荡模式能被更好地抑制。最后采用粒子群优化算法求得最佳的PSS参数。四机两区域系统中的仿真结果表明，相比传统的基于负阻尼机理设计的PSS，所提方法设计的PSS能够更加均衡有效地抑制共振机理低频振荡，同时不影响其原有的对负阻尼低频振荡的抑制效果。%Low-frequency oscillation (LFO) of resonance mechanism could still happen after installing PSS which is the most common method of suppressing LFO. This paper deduces the mathematical expression of the amplitude of LFO of resonance mechanism and analyzes the influencing factors. Then, a design method of PSS for suppressing LFO of resonance mechanism is proposed. In this method, the object function is designed considering both the phase and amplitude frequency characteristic to provide better compensation angle and adjust the gain PSS provides. Besides, weight factors are obtained according to the resonance characteristics of each mode, so that the oscillation mode which causes more damage to the power grid can be better suppressed. Particle swarm optimization is used to search the optimal solution. The simulation results in four-machine and two-area system demonstrate that, compared with PSS designed according to negative damping mechanism, PSS designed by the proposed method has better damping effect on LFO of resonance mechanism without affecting the suppression effect of LFO of negative damping mechanism.
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