The application of directional overcurrent relays (DOCRs) plays an important role in
protecting power systems and ensuring their safe, reliable, and efficient operation. However, coordinating
DOCRs involves solving a highly constrained and nonlinear optimization problem. The
primary objective of optimization is to minimize the total operating time of DOCRs by determining
the optimal values for decision variables such as the time multiplier setting (TMS) and plug setting
(PS). This article presents an efficient hybrid optimization algorithm that combines the modified
firefly algorithm and genetic algorithm to achieve improved solutions. First, this study modifies the
firefly algorithm to obtain a global solution by updating the firefly’s brightness and to prevent the
distance between the individual fireflies from being too far. Additionally, the randomized movements
are controlled to produce a high convergence rate. Second, the optimization problem is solved using
the genetic algorithm. Finally, the solution obtained from the modified firefly algorithm is used as
the initial population for the genetic algorithm. The proposed algorithms have been tested on the
IEEE 3-bus, 8-bus, 9-bus and 15-bus networks. The results indicate the effectiveness and superiority
of the proposed algorithms in minimizing the total operating time of DOCRs compared with other
optimization methods presented in the literature.

Title

Energies

Publisher

Energies

Publisher Country

Switzerland

Publication Type

Both (Printed and Online)

Volume

16

Year

2023

Pages

28