Overcurrent Relay Coordination Optimization with Partial Differentiation Approach for the Validation of Coordination Violation

Abstract

Conventional optimization methods for approaching overcurrent relay settings focus on minimizing the operating time of total relays at maximum fault current to accelerate the fault clearance time. However, to judge whether the entire relay curve of each relay pair always meets the constraints of 0.2 or 0.3 sec to the object curve is rather difficult as the curves may have different slopes. Additionally, the coordination time at the closest position for the curves of a relay pair should be checked for coordination validation. Therefore, this work presents a novel partial differentiation approach method to ensure that the curves of overcurrent relay coordination do not intersect with each other and violate the coordination time interval. Relay setting values are normally plotted on the time-current plane to verify the closing or intersection between relay pairs. Thus, a computer program based on the partial differentiation approach is also developed to calculate the current value of the intersection or closest position. Furthermore, a case study involving an industrial power system demonstrates the effectiveness of the proposed method by validating the results of optimization relay coordination.

Directional overcurrent relay coordination by means of genetic algorithms of Chu–Beasley

“…Nowadays, with the improvement of computer and processor capabilities, it is possible to use metaheuristic technique methods to solve the optimization problem, such as Particle Swarm Optimization (PSO) , Genetic Algorithm (GA) and Optimal Techniques (OT) . A comparison of these methods for the optimal coordination of overcurrent relays can be seen in Refs , where the OF is the same as Ref.…”

Half-Interval Method Applied in Feeder Terminal Unit Overcurrent Detecting Curve Setting

“…The lever value of IED2 should be recalculated due to the change of the maximum load current of MTR2. This lever recalculation can be easily performed by the optimal approach described in [17]. Consequently, the overcurrent detecting curve of the total FTUs mounted on the feeders must be changed accordingly.…”

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

“…This results in a LOCAL ONLINE ADAPTIVE TECHNIQUE 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]. This results in a non-linear programming problem with more complicated solution techniques.…”

“…By considering I s as an integer variable and TDS as a continuous variable, a mixed integer non-linear programming has been arranged and solved in [36]. Evolutionary optimization algorithms, such as genetic algorithm (GA) and PSO, have also been applied in solving this non-linear programming problem [31][32][33][34][35]. In [6], a linear programming has been used within the GA to improve its convergence.…”