Optimal coordination of distance relays and non‐standard characteristics for directional overcurrent relays using a modified African vultures optimization algorithm

Abstract Here, an improved version of an African vultures optimization algorithm (AVOA), known as MAVOA is applied to solve the coordination issue between distance relays and directional overcurrent relays (DOCRs). The suggested method enhances the balance between exploration and exploitation features for the AVOA algorithm in order to find the optimal DOCR settings and operating time for zone‐2 distance relays. In 8‐bus, IEEE 30‐bus, and IEEE 39‐bus networks, the ability of the MAVOA technique to find the optimal solution for the coordination between DOCRs and distance relays is evaluated. Both MAVOA and AVOA algorithms are assessed in the case of standard and non‐standard DOCR characteristic curves. The results indicate the significant superiority of the suggested MAVOA algorithm in solving the coordination issue of the combined DOCR and distance relays. The reduction in operating time for DOCRs and zone‐2 of distance relays decreased by about 30% compared to the conventional AVOA technique. The results also prove the MAVOA's superiority over the recently developed algorithm and other algorithms in solving the coordination problem of the combined DOCRs and distance relays. Additionally, the total operating time for the non‐standard characteristic curve for DOCRs results in a reduction of the overall operating time of primary relays of more than 15%.