A Method to Improve Digital Relays Coordination in Power Systems using Particle Swarm Optimization

The protection coordination problem presents a challenge in modern power systems. This coordination must be fast, reliable and easy to set up in order to guarantee suitable performance. This paper presents an optimization tool to determine efficient coordination between digital intelligent electronic devices (IEDs), taking into account the directional overcurrent function. Different from other research, this paper considers inverse-time overcurrent curves types (US and IEC) and discrete settings of pickup current and time multiplier as variables. To achieve this, a method based on Particle Swarm Optimization (PSO) metaheuristic was developed. The results from a 19-bus, 11-transmission line, and 22-relay system are presented, demonstrating the effectiveness of proposed tool.