Meta-Heuristic Technique Based Intelligent Overcurrent and Distance Relay Co-ordination with Novel Relay Minimization Technique

Abstract

Relay coordination is an important aspect to maintain proper power system operation and control. Relays must be organized in such a way that every main relay should have a backup relay and co-ordination time interval (CTI) between primary and back up and different zones of the relays should be maintained to achieve proper fault identification and fault clearance sequences. The relays should operate in minimum desirable time satisfying all the co-ordination constraints. So, relay coordination is nothing but a highly constraint problem. Heuristic techniques are often used to get optimal solution of this kind of problem. In this paper this constraint problem is solved by teaching learning-based optimization (TLBO) on an IEEE 57 bus test system. Proper desirable time setting multipliers (TSM) with minimum operating time of relays are calculated. We also incorporated intelligent over current relay characteristics selection to get the desired results in this work. The results seem to be satisfactory as it is working better when compared with contemporary other techniques like Genetic Algorithm (GA) or Particle Swarm Optimization (PSO). In the later part of the paper a novel relay minimization technique is proposed based on network critical element finding and network graph theory. Keywords: coordination time interval, over current relay characteristics, plug setting, relay coordination, teaching learning-based optimization, time setting multiplier