Improved normalised normal constraint method to solve multi‐objective optimal power flow problem

Abstract

This study proposes an improved normalised normal constraint (NNC) method for solving optimal power flow (OPF), which is formulated as a multi-objective problem. While NNC is an efficient solution method to solve multi-objective problems, it may not cover the entire Pareto frontier in the objective space when three or more objectives are present in the problem, i.e. when the Pareto frontier becomes a hyper-surface. This research work aims to solve this limitation of NNC and propose a more effective solution method, named improved NNC (INNC), for multi-objective optimisation problems with three or more objective functions. The proposed INNC is applied for solving multi-objective OPF problem with three objectives of generation cost, transmission loss and voltage regulation. The effectiveness of the proposed INNC method for solving the multi-objective OPF problem is extensively illustrated on the IEEE 30-bus and IEEE 118-bus test systems in comparison with several recently published multi-objective solution approaches.