| Low frequency oscillations phenomenon in power system could cause system instability after a severe disturbance and it could limit power system operation and control. Therefore, attenuating these oscillations has to be accomplished effectively, so the system remains stable and reliable. Thus, the objectives of this research are to investigate the existence of such phenomenon in a real large-scale power system and then scrutinize the impact of three controller design approaches on enhancing its overall dynamic stability. It is worth to mention that instead of using the complete model of the power system to perform the analyses, a reduced version is utilized. The latter is constructed via developing a systematic approach for building static and dynamic equivalent of such huge power system. The first controller design approach inspects a coordinated design between a proposed and existing Power System Stabilizers (PSSs). The second approach studies an individual design of a proposed Thyristor Controlled Series Capacitor (TCSC) based stabilizer. The last approach tests a simultaneous design of the aforementioned PSSs and TCSC. In each case, the design problem is manipulated and solved by a novel technique integrating a Modified Particle Swarm Optimization technique (MPSO) with nonlinear time-domain simulations. The objective function of the MPSO is based on nonlinear fitness function for minimizing Integral Time Weighted Absolute Error (ITAE). In all cases, the expected enhancement on the overall dynamic stability is assessed by modal analyses as well as nonlinear time-domain simulations. To examine the robustness of the proposed controllers, their optimized parameters are incorporated into the full power system and then several sever incidents are tested considering different operating conditions. The results show that each method can successfully damp the low frequency oscillations and increase power transfer capability among the weakly interconnected areas with superiority of the third design approach. In addition, this research demonstrates the accuracy of the developed systematic approach for reducing. |
