Optimum Coordination of Overcurrent Relay Timing Using Simplex Method

Bedekar, Prashant P.; Bhide, Sudhir R.; Kale, Vijay

doi:10.1080/15325001003652900

Cited by 64 publications

(41 citation statements)

References 17 publications

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“…During optimal coordination, some or all of these adjustments may be considered as optimization variables to be determined by solving the optimization problem. Three distinct ideas can be realized in the literature regarding selection of optimization variables: linear programming problem, which can be solved easily and exactly by some versions of the simplex method, regarding that all the problem constraints are valid type [9,30]. 2 Some other references have considered the TDS and I s of the relays as the optimization variables and left the TCC of the relays to be fixed prior to optimization process [6,[31][32][33][34][35][36].…”

Section: Optimal Coordination Of Overcurrent Relaysmentioning

confidence: 99%

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Local online adaptive technique for optimal coordination of overcurrent relays within high voltage substations

Ojaghi

Sudi

Azari

2016

Int. Trans. Electr. Energ. Syst.

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SUMMARYThe optimal coordination of overcurrent relays is an important task in the field of power system protection. Traditionally, this problem is solved with the assumption of the grid being in maximum or minimum loading and dominant topology, that is, the topology in which the grid operates most of the time. However, the grid condition changes during the time because of many reasons. In this paper, by sampling voltage and load current phasors at the high-voltage (HV) bus of a substation, an online method, based on an evolutionary algorithm, is introduced to estimate the grid's Thevenin equivalent viewed from the HV bus. Then, the Thevenin equivalent together with the connection status and short-circuit model of local power transformers and local distributed generations are used to estimate three-phase short-circuit currents in the existing condition of the grid. Finally, these fault currents are used for adaptive optimal coordination of overcurrent relays of the HV substation, such that the optimal coordination of the relays is preserved in all the grid conditions. Case studies, performed on the overcurrent protection of a typical 230/20 kV substation connected to a 9-bus grid, prove desired performance of the proposed online adaptive setting method. Furthermore, this method needs no telecommunications and represents a step toward self-adjusting overcurrent relays.

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Section: Optimal Coordination Of Overcurrent Relaysmentioning

confidence: 99%

“…This formulation, in addition to (3), develops a linear programming problem and is solved by means of the simplex method [9,30].…”

Section: Optimal Coordination Of Overcurrent Relaysmentioning

confidence: 99%

Local online adaptive technique for optimal coordination of overcurrent relays within high voltage substations

Ojaghi

Sudi

Azari

2016

Int. Trans. Electr. Energ. Syst.

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“…OCRs can have variety of characteristics as shown in equation (6) and detailed in Table I [1,6,9,12,13,14] 1 ) ( (6) where, op t is relay operating time, relay I is the current through the relay operating coil, and PS is plug setting. …”

Section: E Constraint Set V -Relay Characteristicsmentioning

confidence: 99%

Determining optimum TMS and PS of overcurrent relays using big-M method

Bedekar

Bhide

Kale

2010

2010 Joint International Conference on Power Electronics, Drives and Energy Systems &Amp; 2010 Power India

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The time of operation of overcurrent relays (OCRs) can be reduced, and at the same time coordination can be maintained, by selecting the optimum values of time multiplier setting (TMS) and plug setting (PS) of OCRs. This paper presents formulation of the problem of determining optimum values of TMS and PS of OCRs as a constrained nonlinear optimization problem, and solution of the same using big-M (penalty) method, which is a method used to find optimum solution of linear programming problem (LPP). The method introduces artificial variables in the objective function to get an initial basic feasible solution (IBFS). Artificial variables are removed using iterative process which also leads to an optimum solution. Index Terms--Backup protection, Big-M method, Nonlinear programming problem, Overcurrent relay coordination.

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“…Several liner programming techniques have been introduced in order to solve coordination problem such as Two-Phase Simplex, Big-M (penalty), Dual simplex, Simplex and interval linear programming methods [14][15][16][17][18]. Due to low number of constrains in LP techniques, intelligence based optimization techniques are utilized to solve the problem [19].…”

Section: Introductionmentioning

confidence: 99%

On-line overcurrent relays setting approach in distribution networks by implementing new adaptive protection algorithm

Zin

Shariati

2015

2015 IEEE Tenth International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP)

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On-Line overcurrent relays setting approach in distribution networks by implementing new adaptive protection algorithmAbstract-In order to meet the ever increasing demand for power, the government has revised its targets in increasing power generation. For this purpose, installation of new equipment or utilization of Distributed Generation (DG) has been employed. In addition to changes in topology of power grid, the amplitude of the short circuit currents also can be affected due to these developments. In this condition, fixed setting for the protective relays cannot respond correctly. In order to prevent any miscoordination or mal-operation, relays have to be adaptively coordinated for a new system configuration to achieve correct fault clearance operation. In this paper, a reliable protection scheme is achieved by implementing the proposed adaptive protection algorithm. As results show, proposed new settings for the relays avoid the risk of unnecessary blackout for distribution network consumers. In addition, sensitive and reliable protection scheme is achieved by implementing the proposed adaptive algorithm.1 978-1-4799-8055-0/15/$31.00 ©2015 IEEE

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Optimum Coordination of Overcurrent Relay Timing Using Simplex Method

Cited by 64 publications

References 17 publications

Local online adaptive technique for optimal coordination of overcurrent relays within high voltage substations

Local online adaptive technique for optimal coordination of overcurrent relays within high voltage substations

Determining optimum TMS and PS of overcurrent relays using big-M method

On-line overcurrent relays setting approach in distribution networks by implementing new adaptive protection algorithm

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