Determination of optimal breakpoint set of overcurrent relays using modified depth‐first search and mixed‐integer linear programming

Abstract

In the process of determination of breakpoints for overcurrent relays (OCR) in power delivery systems, different sets with equal number of OCRs can be selected as minimum breakpoint set (MBPS). Therefore, determination of the most appropriate MBPS is an issue which must be considered. This paper proposes a prioritization between different MBPSs based on the sum of operating times of OCRs. In this case, a set which results the minimum sum of operating times is selected as the appropriate MBPS. For this purpose, the proposed method combines two problems: determination of MBPS and coordination of OCRs, and is expressed in mixed-integer linear programming (MILP) form. Also, a modified depth-first search (DFS) algorithm is applied to determine the OCRs contained loops of studied networks. It is shown that the proposed method has the capability to be combined with previous defined expert rules in this field in order to consider the network conditions in the process of determination of optimal breakpoint set (OBPS). In order to reduce the number of removed coordination constraints, a novel expert rule is added to the existing ones. The proposed method has been implemented on small (8-bus), medium (14-bus and 30-bus) and large (118-bus and 3120-bus) networks, and the results show the effectiveness of proposed method in determining breakpoint set with the least number in first priority and minimum operating times of relays in second priority.

Penggunaan Algoritma Depth First Search Dalam Sistem Pakar: Studi Literatur

“…2020 "Determination of optimal breakpoint set of overcurrent relays using modified depth-first search and mixed-integer linear programming" Algoritma DFS diterapkan untuk menentukan OCR berisi loop dari jaringan yang dipelajari. Metode DFS telah diimplementasikan pada berbagai ukuran jaringan dan hasilnya menunjukkan efektivitas metode yang diusulkan dalam menentukan set breakpoint dengan jumlah paling sedikit dalam prioritas pertama dan operasi minimum kali relay dalam prioritas kedua [19].…”

Relay protection sensitivity integrated optimal placement and capacity of inverter interfaced distributed generators in distribution networks

“…The connection of IIDGs influences the magnitudes and phase angles of fault currents in the lines, thereby adding complexity to the fault analysis in DNs. In power systems, relay protection's sensitivity, selectivity, speed, and dependability are critical factors, with sensitivity being particularly related to the system's fault currents [ [36] , [37] , [38] , [39] , [40] ]. Consequently, the presence of IIDGs can impact the sensitivity of relay protection systems.…”

Coordination of non‐directional overcurrent relays and fuses in active distribution networks considering reverse short‐circuit currents of DGs

“…Genetic algorithm (GA) [20], symbiotic organisms search (SOS) [21], ant colony optimization [22], particle swarm optimization (PSO) [23], biogeography-based optimization (BBO) [24] and simulated annealing algorithm [25] are examples of intelligent algorithms applied to the protection coordination problem. In addition, mathematical algorithms including linear programming [26], mixed-integer linear programming [27][28][29], binary programming [30] and quadratic programming [31] have also been applied to determine the optimal protective device settings.…”