Coordination of PSS and FACTS Damping Controllers in Large Power Systems for Dynamic Stability Improvement

Damping of power system oscillations between interconnected areas is very important for the system secure operation. Power system stabilizer (PSS) and flexible AC transmission systems (FACTS) devices are used to enhance system stability. In large systems multi-machine, using only conventional PSS may not provide sufficient damping for inter- area oscillations. In these cases, FACTS power oscillation damping controllers are effective solutions. But uncoordinated local control of FACTS devices and PSS's may cause destabilizing interactions. In this paper, using objective function which maximizes the function, the total damping ratios of the system are optimized and dynamic stability of the system will be improved. In this method all the operation conditions are considered. Simulation results for a large system and different operation conditions of the system shows that this method has a good efficiency and can be effective solution for this problem in a large system. This method can be effective for the coordinating of multi-controllers in large power systems.