Optimal Capacitor Placement Considering Voltage Stability Margin Based on Improved PSO Algorithm

This paper presents the optimal capacitor placement (OCP) algorithm for the voltage stability enhancement. The problem of OCP is composed by the integer variables and highly nonlinear equations. Generally, this problem can be solved by the OPF algorithms, but the OPF has the defect to solve the problems contained the integer variables and to find the global solution. The particle swarm optimization (PSO) algorithm is the modern heuristic optimization algorithm, so it is easy to treat integer variables and to find the global solution. This paper presents the method for OCP based on the PSO and the method to improve the convergence and search speed of the PSO using the dual variables obtained through the nonlinear interior point method. This algorithm is tested by the NewEngland 39-buses test system.