Optimum design of PSS and SVC controller for damping low frequency oscillation (LFO)

Progressing of the demand for electrical energy leads to loading the transmission system close to their limits which may leads to LFO happening. Low frequency oscillations (LFO) in power system usuallyhappen because of lack of damping torque to overcome disturbances in power system such as changes in mechanical power. Due to the existence of the low frequency oscillation (LFO), the transmission power of AC lines is limited and the system angle stability is affected. In this paper the Parameters of the classic PSS and SVC internal AC and DC voltage controllers are designed in order to damp the Low Frequency Oscillations (LFO). The design of PSS and SVC parameters is considered as an optimization problem and Hybrid Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) are used for searching optimized parameters. The results of the simulation show that the SVC with PID controllers is more effective in damping LFO compared to PSS with PID controllers.