Optimal Sizing of Supercapacitor Energy Storage Based on Firefly Algorithm for Enhancing Critical Clearing Time

In the present day, the electrical power demand is increasing and expected to continue growing. The renewable energy sources as the power supply are also increasing but not much as needed. As a result, the power systems operate close to their maximum stability limit. This paper proposed to extend the value of Critical Clearing Time (CCT) to enhance the stability system, especially the transient stability. A Supercapacitor Energy Storage (SCES) is installed at one of the generator bus; however, the sizing of SCES must be optimized due to the economics and power balance constraint. In this paper, the Firefly Algorithm (FA) is used to obtain the optimal sizing of SCES with the objective function is the highest value of CCT. Lagrange interpolation is used to validate the effectiveness of FA, such as computation time and accuracy. According to the simulation result obtained, the proposed method using FA has a faster calculation time than Lagrange interpolation. Moreover, the proposed method is validated on a modified IEEE 9 bus with various cases. By using FA, the best increase of CCT is obtained when the optimal size of SCES is 0.120 p.u. The overall CCT increase is 0.15766s or around 54.61%.