Optimum Coordination of overcurrent relays using CMA-ES algorithm

Electric Power Systems Research, 2006

In this paper, a new problem formulation is proposed to calculate the optimal relay settings of directional overcurrent relays in power systems. The proposed coordination problem is formulated as a mixed integer nonlinear problem to take into account the discrete values for the pickup current settings. A modified particle swarm optimization (PSO) algorithm is proposed to calculate the optimal relay settings. A comparison between the original particle swarm optimization based method, the proposed PSO algorithm and the GAMS solver is presented.

International Journal on Electrical Engineering and Informatics, 2018

Relay coordination is very important from the point of view of security and healthy operation of power system. Relays should be organized in such a way that every relay should have at least one back up relay and coordination time interval between primary and secondary relays should be maintained. This paper presents the solution of relay coordination problem using Teaching learning based optimization technique (TLBO) by utilizing an IEEE 5 bus and IEEE 30 bus test system. The obtained results are compared with the results obtained from other contemporary meta-heuristic techniques like Genetic Algorithm (GA) and Particle Swarm Optimization technique (PSO). It is observed that TLBO is the best among those with respect to process speed. After this we have done an extension of the work by introducing critical element and network graph theory based relay minimization technique. It is expected that this analysis will be helpful to maintain the network reliability and healthy flow of power.

2011

Protection of power transmission has an important role in power systems. To have a better protection it is common to combine difference types of relays, which combination of overcurrent and distance relays is a well-known protection scheme in transmission lines. Another thing, which should be considered is defining a backup protection system that clear fault when main protection clear the fault. To achieve this aim, coordination between primary and backup protection systems should be performed. Speed, selectivity and stability are constraints, which must be satisfied by performing coordination, and sometimes it is so hard by conventional methods. Therefore, considering coordination of relays as an optimization problem and solving this problem by intelligent methods can be effective. Many intelligent methods have been suggested performing coordination between overcurrent and distance relays. In this paper, an optimal coordination of overcurrent and distance relays is proposed, which uses a hybrid Particle Swarm Optimization (PSO) with a new assumption that satisfies all constraints.

2010

The main function of the protective devices in the power system is to detect and remove the selected faulty parts as fast as possible. Directional over current relays are commonly used for the protection of interconnected sub transmission systems, distribution systems, or as a secondary protection of transmission systems. For the systems having more than one source connected, that is meshed or looped networks, directional over current relays become the suitable choice for better selectivity, since directional relays operate only when the fault current flows in the specific tripping direction desired. The most vital task when installing directional relays on the system is selecting their suitable current and time settings such that their fundamental protective functions are met under the requirements of sensitivity, selectivity, reliability and speed. The problem of setting Directional Over Current Relay(DOCR) is a highly constrained optimization problem that has been solved as a linear programming problem. The calculation of the time dial setting (TDS) and pick up current (IP) setting of the relays is the core of the coordination. This paper calculates the TDS by choosing one of the available pick up current settings as the predetermined value. The simplex two phase method is used to determine the optional TDS of the relays. Improvement in the solution is brought by using the particle swarm optimization technique to the co-ordination problem for reaching the global optimum value with less computational time. Sample 3 bus and 8 bus systems are utilized for comparing the results obtained by PSO with that of the simplex method. The optimization method used in the recent times minimizes the operating time of the relays much, when compared to the other methods. This method also enhances quicker solution of coordination process.

International Journal of Smart Grid and Clean Energy, 2020

The protection of electrical distribution network with multiple loops and bidirectional power flow needs optimal coordination of directional overcurrent relays (DOCRs). The DOCRs coordination is highly non-linear and largely constrained optimization problem where plug settings (PS) and time dial settings (TDS) of DOCRs are set as control variables. The objective function in this paper is based on minimizing the operating time of all primary DOCRs considering far-end and near-end fault approach. The optimization is performed with particle swarm optimization (PSO) for standard test systems of 3-bus, 4-bus and 6-bus and the results are compared with the existing methods of relay coordination reported in literature. The optimized PS and TDS for DOCRs has resulted in the least value of objective function along with proper coordination time interval for all test systems.

AIP Conference Proceedings

Cempaka Substation becomes one of the existing electricity distribution systems in South Kalimantan. As a transmission line, a reliable protection system is required having s proper relay coordination, thus indicating thereby optimizing the electricity distribution. This study aims to navigate the value of the relay setting, optimization is required to find the optimal value for the relay setting. The optimization applied is Particle Swarm Optimization (PSO) to produce optimal values for relay settings. The calculation is conducted with the help of MATLAB software. The result of the calculation presents the value of the time dial setting (TDS) and the value of the pickup current (Ip). Furthermore, the value from the calculation results is entered into the simulation utilizing ETAP software in order to navigate the results of the protection relay setting when a disturbance occurs. The standards which are applied as references in this study include local standards or international standards such as SPLN, IEC 60947. Thus, from the research that was performed conducted, the distance between the primary relay and backup was 1.2 seconds fulfilling the standard of a reliable protection system of 0.3 seconds.

Several optimal coordination of overcurrent relays have been done in the past by using linear programming such as simplex, two-phase simplex and dual simplex and also intelligent optimization techniques such as genetic algorithm (GA) techniques. In this paper, a powerful optimal coordination method based on GA is introduced. The objective function (OF) is developed in a such way that in addition to the coordination of overcurrent relays, the coordination of overcurrent and distance relays is also achieved. In other words, the novelty of the paper is the modification of the existing objective function of GA, by adding a new term to OF to fulfill the coordination of both overcurrent and distance relays. The method is applied to two power network systems and from the obtained results it is revealed that the new method is efficient and accurate.

The inverse definite minimum time relay has been used in the power distribution system in order to protect the system from power system faults.

… Journal Of Electeical Power and Energy …, 2008

Over Current Relays (OCRs) and Directional Over Current Relays (DOCRs) are widely used for the radial protection and ring sub transmission protection systems and for distribution systems. All previous work formulates the DOCR coordination problem either as a Non-Linear Programming (NLP) for TDS and Ip or as a Linear Programming (LP) for TDS using recently a social behavior (Particle Swarm Optimization techniques) introduced to the work. In this paper, a Modified Particle Swarm Optimization (MPSO) technique is discussed for the optimal settings of DOCRs in power systems as a Non-Linear Programming problem for finding Ip values of the relays and for finding the TDS setting as a linear programming problem. The calculation of the Time Dial Setting (TDS) and the pickup current (Ip) setting of the relays is the core of the coordination study. PSO technique is considered as realistic and powerful solution schemes to obtain the global or quasi global optimum in optimization problem.

2016 Future Technologies Conference (FTC), 2016

In power system properly coordinated protection scheme is designed to make sure that only the faulty part of the system will be isolated when abnormal operating condition of the system will reach. The complexity of the system as well as the increased user demand and the deregulated environment enforce the utilities to improve system reliability by using a properly coordinated protection scheme.This paper presents overview of overcurrent relay coordination techniques. Different techniques such as Deterministic Techniques, Meta Heuristic Optimization techniques, Hybrid Optimization Techniques and Trial and Error Optimization Techniques, have been reviewed in terms of method of theirimplementation, operation modes, nature of distribution system and finally their advantages as well asthe disadvantages.