Directional Overcurrent Relays and the Importance of Relay Coordination

When two protective apparatus installed in series have characteristics, which provide a specified operating sequence, they are said to be coordinated or selective. The coordination of directional overcurrent relays poses serious problems in the modern complex power system networks, which are interconnected. Researchers have looked upon the problem of coordination from different considerations by making use of computer aids. Many efforts have been made to the automation of the coordination process in the area of relay coordination. This paper compiles the most of the significant developments in the area of time-overcurrent relay coordination using different techniques and methodologies. It is hoped that this work will be useful for future generation researchers to find the relevant references to advance the research work in future.

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Smart Protection Scheme For Radial Distribution System

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.f9360.088619 ◽

2019 ◽

Vol 8 (6) ◽

pp. 3621-3624

Keyword(s):

Power System ◽

Differential Evolution ◽

Distribution System ◽

Coordination Problem ◽

Radial Distribution System ◽

Protection Scheme ◽

Relay Coordination ◽

Overcurrent Relays ◽

Optimal Coordination ◽

Real Time Simulations

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.

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Optimized Overcurrent Relay Coordination in a Microgrid System

Recent Advances in Computer Science and Communications ◽

10.2174/2666255813666191204142320 ◽

2019 ◽

Vol 13 ◽

Author(s):

O.V.Gnana Swathika ◽

K.T.M.U. Hemapala

Keyword(s):

Simplex Algorithm ◽

Protection Scheme ◽

Distributed Generators ◽

Fault Currents ◽

Relay Coordination ◽

Protection Strategies ◽

Overcurrent Relays ◽

Overcurrent Relay ◽

Dual Simplex ◽

Dual Simplex Algorithm

: Microgrids are a conglomeration of loads and distributed generators at a distribution level network. Since this network is no longer a single source fed network, the typical protection strategies may not be deployed. Reconfiguration is a topology changing feature that is visible in microgrid. This is also another factor that is to be considered while protecting the microgrid setup. This paper proposes a protection scheme that has normal and fault currents captured for all topologies of the microgrid. For each topology, the optimized time multiplier settings of overcurrent relays are computed using Dual Simplex Algorithm. This aids in clearing the fault as fast as possible from the network. A 21-bus microgrid system is considered and the optimized overcurrent relay coordination scheme is realized for the same.

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A Fast Directional Overcurrent Relay Coordination Method for Smart Grid Protection

10.53316/sepoc2021.045 ◽

2021 ◽

Author(s):

KLAUS TESSER MARTIN ◽

ADRIANO CAVALHEIRO MARCHESAN ◽

OLINTO CéSAR BASSI DE ARAúJO ◽

GHENDY CARDOSO JUNIOR ◽

MARCELO FREITAS DA SILVA

Keyword(s):

Smart Grid ◽

Power Systems ◽

Smart Grids ◽

Test System ◽

Topological Change ◽

Relay Coordination ◽

Overcurrent Relays ◽

Overcurrent Relay ◽

Optimal Adjustment

Modern power systems are dynamic and complex. Likewise, smart grids bring opportunities for the development of protection relays, such as the ability to communicate remotely. Based on these opportunities, this paper proposes a method of coordinating directional overcurrent relays capable of quickly obtaining the optimal adjustment of the relays with each topological change in the network. The proposed methodology is applied in different cases to a test system, demonstrating its effectiveness and potential.

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Overcurrent and Earthfault Relay Coordination for Microgrid with Numerical Relay Features

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.c8456.019320 ◽

2020 ◽

Vol 9 (3) ◽

pp. 1626-1630

Keyword(s):

Distribution System ◽

Short Circuit ◽

Renewable Energy Sources ◽

Short Circuit Current ◽

Load Flow ◽

Active Distribution System ◽

Relay Coordination ◽

Overcurrent Relays ◽

Numerical Relay ◽

Short Circuit Analysis

This Paper deals with the Relay Coordination for microgrids by considering the symmetrical and unsymmetrical faults. A microgrid is an active distribution system in which the renewable energy sources and loads connected to feeders operate parallel or autonomously from the main power grid. In a microgrid, Overcurrent relays can be used as the protection device. When there is changeover from grid connected to islanded mode or disconnection of DG will lead to variation in short circuit current. So, the relay may fail to operate or there will be delay in operation. Relay Coordination is done on the basis of load flow and short circuit analysis. Simulation is done using the ETAP (Electrical Transient and Analysis Program) Software by taking the 9 bus 18 node system.

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