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Abstract
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A single machine-infinite-bus (SMIB) system including the interline power flow controllers (IPFCs) and the power system
stabilizer (PSS) controller is addressed. The linearized system model is considered for investigating the interactions among IPFC and
PSS controllers. To improve the stability of whole system again different disturbances, a lead-lag controller is considered to produce
supplementary signal. The proposed supplementary controller is implemented to improve the damping of the power system low
frequency oscillations (LFOs). Imperialist optimization algorithm (ICA) and shuffled frog leaping algorithm (SFLA) are
implemented to search for optimal supplementary controllers and PSS parameters. Moreover, singular value decomposition (SVD)
method is utilized to select the most effective damping control signal of IPFC lead-lag controllers. To evaluate the system
performance, different operating conditions are considered. Reponses of system in five modes including uncoordinated and
coordinated modes of IPFC and PSS using ICA and SFLA are studied and compared. Considering the results, response of system
without controller shows the highest overshoot and the longest settling time for rotor angel at the different operating conditions. In
this mode of system, rotor speed has the highest overshoot. Rotor angel in the system with only PSS includes lower overshoot and
oscillation than system without controller. When PSS is only implemented, rotor speed deviation has the longest settling time. Rotor
speed deviation in the uncoordinated mode of IPFC and PSS shows lower overshoot than system with only PSS and without
controller. It is noticeable that in this mode, rotor angel has higher overshoot than system with only PSS. The superiority of the
suggested ICA-based coordinated controllers is obvious compared with SFLA-based coordinated controllers and other system modes.
Responses of coordinated PSS and IPFC SFLA-based supplementary controllers include higher peak amplitud
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