A robust approach for coordination of directional overcurrent relays in active radial and meshed distribution networks considering uncertainties

Abstract

Summary Penetration of distributed generations in distribution networks (active distribution networks) has resulted in some problems such as change in short circuit level and direction of fault current flow. Such conditions may cause some relays to malfunction. In this paper, a method for coordinating directional overcurrent relays in active distribution networks taking uncertainties into consideration is proposed. These uncertainties include changes in operation conditions, changes in fault conditions, error in measuring equipment, and outage of distributed generations. Therefore, an optimization frame with new variables is presented, which can be used to create different characteristic curves. Taking uncertainties into account causes the number of constraints to increase and the problem of coordination of directional overcurrent relays to become more complicated. Thus, a two‐step approach is used to solve this problem. In the first step, an algorithm is used to form the constraints of the problem, then, in the second step, a hybrid optimization algorithm consisting of the cuckoo search algorithm and linear programming is proposed. The simulation results for active radial and meshed distribution networks are presented to demonstrate the effectiveness of the proposed approach.

Novel stepwise and combined stepwise–piece‐wise linear tripping characteristics for coordinating numerical overcurrent relays

“…The next relay (R 3 ) is to mainly protect the line section between the buses B3 and B4 (L34) and to provide a backup protection for Table 1 Pros and cons of different NSCs introduced in various references Reference Advantage Disadvantage [7] Preserving constant CTI between the main/backup relay pairs for entire fault current range Unnecessary increase of time delay by moving the fault location along the main and backup protection zones of the relay Stabilising against the cold load/hot load pickup currents without increasing relay time delay against the higher fault currents Limited number of ahead relays Directly applicable with the existing industrial OCRs [9] Reducing overall operating times of the relays compared to SCs Coordination problem during dynamic change of the fault current Less flexibility [10][11][12][13] Reducing overall operating times of the relays compared to SCs Needing to measure the fault voltage in addition to the fault current Needing to set an extra set point Inapplicable with the exiting OCRs [14] Reducing overall operating times of the relays compared to SCs Inapplicable with the exiting OCRs Removing the drawback of general increase of operating time by moving the relay location towards the source Increasing number of parameters to set in large-scale power systems [15][16][17][18][19][20][21][22][23] Offering more desirable and flexible characteristic Increasing computation burden for coordination Reducing overall operating times of the relays Inapplicable with the exiting OCRs Needing to set some extra set point [24] Offering more desirable and flexible characteristic Increasing time interval between the main/backup relay pairs by decrease of the fault current Reducing overall operating times of the relays Inapplicable with the exiting OCRs [25] Preserving constant CTI between the main/backup relay pairs for entire fault current range Difficulty to apply to the large-scale meshed grids…”

“…The other way of forming a NSC is to consider the constant parameters of the SCs as variable set points. This approach was employed in [15][16][17][18][19][20][21][22][23] by considering the constants A, B and C of the IEEE standard characteristics [4] as variable set points. This way, more desirable and flexible TCCs with reduced operating times were achieved for the relays.…”

An info‐gap risk‐averse optimization model for coordination of overcurrent protective relays considering power system uncertainty

“…Heretofore, different mathematical techniques and evolutionary algorithms are proposed in the literature to solve the coordination problem of the overcurrent relays. Among them are referred the genetic algorithm, 3,4 hybrid genetic algorithm, 5 particle swarm optimization, 6 modified particle swarm optimization, 7,8 differential evolution algorithm, 9 artificial bees colony algorithm, 10 water cycle algorithm, 11 seeker algorithm, 2 modified seeker algorithm, 12 improved firefly algorithm, 13 improved harmony search algorithm, 14 electromagnetic field optimization, modified electromagnetic field optimization, 15 hybrid biogeography‐based optimization with linear programming (LP), 16 modified adaptive teaching learning‐based optimization algorithm, 17 modified particle swarm optimization‐interval LP approach, 18 non‐dominated sorting genetic algorithm‐II, 19 and combination of cuckoo search and LP algorithms 20 . However, evolutionary algorithms suffer from the drawback in procuring an optimistic convergence of solutions due to highly variables and constraints 17 .…”

“…Coordination of the overcurrent relay problem is solved assuming that the network configuration and nominal set‐points are fixed. But network configuration is changing due to changing in operating conditions, 20 single‐line outage, 27 transformers, and generation unit contingencies occasionally. These topological and operational uncertainties may cause fault current uncertainty and ultimately could lead to the ineffective coordination of the overcurrent relays.…”

Coordination Index for Directional Overcurrent Relays using Multiobjective C-DEEPSO Approach

“…Moreover, the optimal coordination of DORs has been intensively studied in recent years (Rajput et al, 2018;Shabani and Karimi, 2018;Bernardes et al, 2015). The protection systems using DORs are considered as backup protection of protection of transmission systems, working with distance relays, and as primary protection of distribution or sub-transmission.…”