Investigating voltage stability problem in the electrical power system using gravitational search algorithms

This study aims to utilize the Gravitational Search Algorithm (GSA) to find the optimal values of the proportional integral derivative (PID) controller parameters to control the automatic voltage regulator (AVR). GSA is categorized as a heuristic algorithm. In finding the optimal values, we try to minimize the performance index also called the error in the closed loop control diagram. We observed and compared the three different situations of the error, namely the integrated absolute error (IAE), the integral of squared error (ISE), and the integral time absolute error (ITAE). We, then, employed a conventional Ziegler-Nicolas Method (ZNM) to find the optimal values under the same conditions with GSA. The values obtained through both methods are compared at the end. We show that the proposed method using GSA has a better performance than ZNM in terms of settling time, oscillations and overshoot. We also compared our results with the ones obtained through Genetic Algorithms (GA). Similarly, our method performs better.