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Abstract
The protection system plays a crucial role in the generation, transmission, and distribution systems of a power network. Among various protection relay types, Directional Overcurrent Relays (DOCRs) are the most used. When abnormal conditions are detected, these relays trigger the tripping of protection devices by detecting the direction and magnitude of current flow and isolating faulty parts of the system. The present article proposes a novel approach for the coordination and settings of DOCRs using the Growth Optimizer (GO) algorithm; the main objective is to minimize the sum of operation time of the relays while ensuring the minimal time gap between primary and backup relays. This optimization problem is subject to different constraints including maximum allowable operating times, relay coordination margins, and discrete values for pickup current settings. The technique is applied to the IEEE 4-bus, 8-bus, and 15-bus test systems, and its performance is compared with that of other optimization algorithms. Results show that the proposed approach provides the proper coordination of protection systems with a high, robust, and computationally acceptable speed of convergence.
Keywords: Growth Optimizer, Protection, Overcurrent Relays, Optimization, Coordination.
(ProQuest: ... denotes formulae omited.)
1. Introduction
In the power system, the electricity is transmitted and distributed through a complex network of lines. Various faults and abnormalities may occur in this network, such as short circuits and overloads.
Thus, a robust and reliable protection system is needed to detect and isolate these faults to ensure the power system's stability.
Directional Overcurrent Relays (DOCRs) are commonly used in distribution and sub-transmission systems as primary protection against overcurrent.
The relays detect overcurrent conditions and trip the circuit breakers to disconnect the faulty sections when overcurrent is detected.
The complexity of power systems and the need for minimal operating time while maintaining adequate coordination margins make it challenging to coordinate these DOCRs.
To solve this challenge, several optimization algorithms have been proposed in the literature to optimize the coordination and settings of DOCRs.
In general, there are two types of optimization algorithms: traditional algorithms and nature-inspired algorithms [1], [2].
The authors of article [3] proposed an optimization model based on Imperialistic Competition (IC), which is a socio-political algorithm that strives to minimize the operating times of relays while maintaining coordination margins and discrete...