Optimal Coordination of Standard and Non-Standard Direction Overcurrent Relays Using an Improved Moth-Flame Optimization

Ahmed Korashy,Salah Kamel,Francisco Jurado,Thamer Alquthami

doi:10.1109/access.2020.2992566

Abstract

In this paper, an efficient optimization technique, called improved moth-flame optimization (IMFO) is proposed to improve the performance of conventional Moth-flame optimization (MFO). Then, both of MFO and IMFO are applied to solve the coordination problem of standard and non-standard directional overcurrent relays (DOCRs). In the proposed IMFO, the leadership hierarchy of grey wolf optimizer is used to improve the performance of conventional MFO with the aim of finding the best optimum solution. The major goal for optimal coordination of DOCRs is to minimize the total operation time for all primary relays as well as satisfy the selectivity criteria between relay pairs without any violation in the operating constraints. The performance and feasibility of proposed IMFO are investigated using three different networks (8-bus network, 9-bus network, and 15-bus). The proposed IMFO is compared with conventional MFO and other well-known optimization techniques. The results show the effectiveness of the proposed IMFO in solving both standard and non-standard DOCRs coordination problems without any violation between primary and backup relays. In addition, the results show the power of proposed IMFO in finding the best optimal relay settings and minimizing the total operating time of relays which its reduction ratio reaches more than 28% with respect to the conventional MFO. Furthermore, the reduction in the total operating time of primary relays reaches more than 50 % with the usage of the non-standard relay curve.

Highlights

Protective relays play an important role in saving continuity of the electric power network
The proposed improved moth-flame optimization (IMFO) is compared with other well-known optimization algorithms (EFO [19], DE [23], MEFO[19], particle swarm optimization (PSO) [23], Modified water cycle algorithm (MWCA) [1], WCA [1], HS [12], SQA [24], GSA [24], genetic algorithm (GA)-Non-Linear Programming (NLP) [25], GSA-sequential quadratic programming (SQP) [24], biogeography-based optimization (BBO)-Linear programming (LP), GA [23], CSA [26], SFSA [17], SA [5], BSA [27], EBSA [28], GSO [29], ER-WCA [30], WOA [31], HWO [31], FA [32], IFA [32], DJAYA [34], and OJAYA [34]) to show its superiority in finding the optimal solution for the coordination problem of directional overcurrent relays (DOCRs)
Both of Moth-flame optimization (MFO) and IMFO have been applied for solving the optimal coordination problem of DOCRs

Summary

Introduction

Protective relays play an important role in saving continuity of the electric power network. The main goals of a protective relay are to isolate only fault part quickly, keep healthy parts in service, and maintain the reliability of the electric network. The coordination problem of DOCRs is considered as a non-linear optimization problem with many operating. In optimal coordination of DOCRs, the right chosen of these settings is very important [4]. The primary relay shall isolate faults quickly in its own area to minimize the system outage to the smallest area. The main goal of optimal coordination of DOCRs aims to minimize the summation operating time for all relays and keep a time margin between backup and primary relays [6]. Different methods have been reported to find the optimal solution for relays coordination problem.

Objectives

Results

Conclusion