In this paper, the modified linearized Phillips-Heffron model is utilized to theoretically analyze a single-machine infinite-bus (SMIB) installed with SSSC. Then, the results of this analysis are used for assessing the potential of an SSSC supplementary controller to improve the dynamic stability of a power system. This is carried out by measuring the electromechanical controllability through singular value decomposition (SVD) analysis. This controller is tuned for simultaneously shifting the undamped electromechanical modes to a prespecifed area in the s-plane. The issue of designing a robustly SSSC- based controller is considered and formulated as an optimization problem according to the eigenvalue-based multi-objective function consisting of the damping ratio of the undamped electromechanical modes and the damping factor. Next, considering its high capability to find the most optimistic results, the Gravitational Search Algorithm (GSA) is used to solve this optimization problem. Wide ranges of operating conditions are considered in design process of the proposed damping controller in order to guarantee its robustness. The effectiveness of the proposed controller is demonstrated through eigenvalue analysis, controllability measure, nonlinear time-domain simulation and some performance indices studies. The results show that the tuned GSA based SSSC controller which is designed by using the proposed multi-objective function has an outstanding capability in damping power system low frequency oscillations, also it significantly improves the power systems dynamic stability.

This paper objective presents static synchronous series compensation FACTS device with biogeography based optimization (BBO) to deal for obtaining worthwhile power flow control. The biogeography based optimization method is utilized to find the optimal fitted child sets by surviving parents with the help of migration and mutation Jaipur process. The present BBO technique from the evolutionary strategy with static synchronous series compensator provides improved outcomes in comparison to other optimization methods. The simulation outcomes illustrate that the proposed BBO algorithm is efficacious, secure and correct to search the optimized values with SSSC based FACTS devices. The proposed method is considering the solution quality an optimistic substitute method for extricating the OPF problems. The simplification and effectiveness of this method are validated on the IEEE 57 bus and 75 bus Systems. In this paper, from the outcome results, it is clearly shown that the proposed technique execution can be properly and effectively applied to the optimal position of multiple OPF problems. i.e. BBO based algorithm with SSSC FACTS device is found better results when compared to without SSSC device in all aspects.