Hybrid VNS–LP algorithm for online optimal coordination of directional overcurrent relays. Issue 23 (21st October 2020)

• Record Type: Journal Article
• Authors: Damchi, Yaser; Dolatabadi, Mohammad
• Is Part Of: IET generation, transmission & distribution. Volume 14:Issue 23(2020)
• Page Start: 5447
• Page End: 5455
• Publication Date: 2020-10-21
• Subjects: smart power grids -- power system interconnection -- optimisation -- overcurrent protection -- relay protection -- search problems -- power system protection; online optimal coordination -- directional overcurrent relays -- DOCR -- interconnected power systems -- nonconvex optimisation problem -- nonlinear optimisation problem -- linear programming problems -- variable neighbourhood search framework -- pickup current settings -- continuous variables -- discrete variables -- coordination problem‐solving -- VNS algorithm -- online coordination -- smart grids applications -- low‐level programming environment -- hybrid VNS–LP algorithm -- VNS framework -- elementary arithmetic -- RAM; Electric power production -- Periodicals; Electric power transmission -- Periodicals; Electric power distribution -- Periodicals; 621.3105
• DOI: 10.1049/iet-gtd.2019.1811
• Languages: English
• ISSNs: 1751-8687

Abstract

Abstract : Optimal coordination of directional overcurrent relays (DOCRs) in interconnected power systems is a highly constrained, non‐convex and non‐linear optimisation problem. In this study, use of a series of linear programming (LP) problems in a variable neighbourhood search (VNS) framework is proposed, in which pickup current settings can be considered either as continuous or discrete variables. Therefore, the proposed hybrid algorithm (VNS–LP) is suitable for coordination problem‐solving in a network with different types of DOCRs. Furthermore, two versions of the VNS algorithm are proposed, the first of which is very easy to implement, while, the other is somewhat more sophisticated, and at the same time much faster and possibly suitable for online coordination in smart grids applications. One advantage of the second algorithm is that it relies only on elementary arithmetic and requires low RAM, which makes it implementable in any low‐level programming environment. This, in turn, can increase the interoperability, which is of crucial importance when automating tasks. The efficiency of the proposed algorithm was investigated in several test systems. Numerical results indicate that the two proposed approaches outperform the previous methods. Moreover, the coordination problem is solved in a reasonably short time using a faster approach.