An Effective Damping Control Scheme to Improve Inter-Area Power System Stability

In a large and complex interconnected power system with long transmission lines, the inadequate damping scheme for the inter-area oscillations may lead to system instability. This issue is commonly solved by employing a power system stabilizer (PSS) to increase the system damping. However, the use of PSS encounters some limitations that include voltage fluctuation and poor performance in damping significant oscillations that result due to three-phase faults. To improve the damping of the inter-area oscillation modes, a unified power flow controller (UPFC) along with the PSS is proposed in this paper. Simultaneous utilization of PSS and UPFC calls for proper coordination to attain an optimal damping performance. Hence, a method to obtain optimal coordination between the PSS and UPFC by employing the Firefly algorithm is proposed. To verify the effectiveness of the proposed method, the performance of the proposed damping scheme is analyzed through simulation analysis. Simulation results show the effectiveness of the proposed method in damping low as well as large oscillations in the power systems.