On-line coordination of directional overcurrent relays: Performance evaluation among optimization algorithms

• Formulation of coordination problem using differential evolution algorithm.
• Coordination problem is performed on-line.
• Comparison among GA, ACO and DE for the coordination problem.
• Evaluating speed, result quality, robustness and convergence ability; the DE outperformed.

The coordination of directional overcurrent relays is most commonly studied based on a fixed network topology in a mesh electrical system. However, in real life, the network topology and the operation of elements of sub-transmission and distribution systems are constantly changing. In addition, modern electrical systems tend to operate near boundary conditions to satisfy the clients. As a result, the directional overcurrent relays (DOCRs) lose speed and sensitivity. Therefore, the principal objective of this paper is to perform on-line coordination of the directional overcurrent relays in order to enhance speed and sensitivity. The secondary objective is to formulate the differential evolution algorithm and compare it with the genetic algorithm and ant colony algorithm. The objectives were accomplished by developing an on-line algorithm that worked with the optimization algorithms.