Investigation of stability problems in electrical power systems with gravitational search algorithm

Nowadays, demand for qualified and reliable energy increases gradually depending on the increase in the need for electricity energy. There is an obligation to serve the electricity energy with constant voltage and frequency. This situation causes stability problems in electricity power systems. Production of the electricity energy is satisfied by the synchronized generators depending on the electricity energy demand. Since the electricity power systems have an interconnected structure, it is required to be synchronized from all the generators in the system. After either a big or small destructive effect that may occur in the system, there exist oscillations in voltage and speed values of synchronized generators. The voltage and load frequency control in power systems appear in between the basic stability problems with the purpose of to amortize this oscillations.In this study, a PID controller whose coefficients are determined via GSA to prevent oscillations and to fix the best settling for AVR (Automated Voltage Regulator) and LFC (Load Frequency Controller). Matlab-Simulink models are established for PID controls of sample power systems and transfer functions are obtained. PID coefficients are found first via ZN method under different working conditions. Then, the same values are obtained with GA and YAA. The results are compared. The study is realized separately for AVR and LFC. According to the results obtained, in both applications of AVR and LFC, it is seen that the system reaches the shortest settling time with less oscillations in case of using PID.