Mitigation of low frequency oscillations in power systems based on Mamdani fuzzy inference

Abstract

Several methods have been proposed and implemented to improve the power system stability. Based on the theory of proportional-integral-derivative (PID) excitation control and the composition principle of fuzzy PID controller, a novel PID controller based on Mamdani fuzzy inference (MFPID) is proposed in this paper. The proposed controller realizes the self-adjustment of the excitation controller parameter. Furthermore, the MFPID and power system stabilizer (PSS) subsection switch control strategy (MFPID-PSS) is presented based on the advantages of PSS and MFPID. In MFPID-PSS strategy, by switching the control strategy between MFPID and PSS at appropriate moment, the MFPID-PSS method acquires the overshoot as small as PSS, and at the same time acquires the adjusting time as short as MFPID. The simulation results demonstrate that the MFPID-PSS method improves the power system stability and has better mitigation effect for low frequency oscillations in power systems after disturbances.