Co-ordination of overcurrent voltage controlled protection in large electrical networks using particle swarm optimization technique

Coordination between generator overcurrent voltages controlled relays (51 V) and transmission line directional overcurrent relays (67) represent a tedious task in power system protection. It depends heavily on network behavior and system parameters. Mis-coordination is sometimes happened between the two relays. In this paper an intelligent modular protection system is proposed for relays parameter setting to assure proper coordination between such relays due to the great important of generation stations. Overcurrent voltage controlled relays are usually used as backup protection of generators. The proposed co-ordination system is based on Particle Swarm Optimization technique (PSO). The developed system interacts successfully with the protected network, taking into consideration different loading and operating schemes. The system is applied and tested on large unified electrical power network. Good results are obtained to assure perfect coordination in different fault type, location and network behaviors.