Enhanced Discrete Differential Evolution to Determine Optimal Coordination of Directional Overcurrent Relays in a Power System

Author(s):  
Joymala Moirangthem ◽  
Subranshu Sekhar Dash ◽  
K. R. Krishnanand ◽  
Bijaya Ketan Panigrahi

In this paper,the study of optimal coordination of directional overcurrent relays along with relay communication in HV substations is proposed. The relay coordination problem is non linear.It typically consist of two groups of control variables(Time Dial Settings:TDS and Plug Settings:PS). The purpose of relay coordination is to propose the suitable settings for all releases and ensure the coordination. The differential evolution is employed to solve for solutions of optimal relay coordination. The relay coordination is mainly done to improve selectivity of the relay to particular fault. ETAP is so popular for its capability for modelling of power system networks and analyzing various studies and Real Time simulations.


2015 ◽  
Vol 16 (3) ◽  
pp. 389
Author(s):  
Farhad Namdari ◽  
Sajad Samadinasab ◽  
Nader Shojaei ◽  
Mohammad Bakhshipour

The duty of protective systems is the timely detection of fault and removing it from the power network. The accuracy of the results and reducing the execution time of the optimizing algorithm are two crucial elements in selecting optimizing algorithms in protective functions. The most important protective elements that are used in power networks are distance and overcurrent relays. In this article, a new algorithm is presented to solve the optimization problem of coordination of overcurrent and distance relays by using Cuckoo Optimization Algorithm which considers the non-linear model overcurrent relays at all stages of setting. The proposed method is tested on a standard 8-bus power system network. Also the results obtained have been compared with other evolutionary algorithms. The results show that the proposed approach can be provide more effective and practical solutions to minimize the time function of the relays and achieving optimal coordination in comparison with previous studies on optimal coordination of overcurrent and distance relays in power system networks.


In modern power system, protective relays are playing a vital role for protection of the whole system. The efficiency and reliability of whole protection system depends upon the combined and coordinated operation of protective devices such as relays, circuit breakers etc. Moreover, both types of relays viz., primary and backup relays have been used for smooth and reliable operation of the power system from years. A primary directional over current relay (DOCR) is setup for the fast response of any faulty condition. If it fails, then backup relay perform the same task after some time gap. Three different setting such as plug-setting multiplier (PSM), pickup current settings and time multiplier setting (TMS) are required of performing the operation. In this paper, three very popular swarm based meta-heuristic such as particle swarm optimization (PSO), artificial bee colony (ABC) and a recent hybridization of both, i.e., hybrid ABC-PSO have been implemented for the calculation of optimal coordination problem. This coordination problem is treated for continuous settings optimization for TMS and pickup current. An IEEE 8 bus system without grid has been opted for validation of the results. It is evident from the study that the hybrid ABC-PSO based proves to generate optimal solution providing better convergence rate as compared to individual PSO and ABC algorithm.


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