In this paper, strength Pareto evolutionary algorithm (SPEA) is applied to solve the multiobjective optimal reactive power (VAR) dispatch problem. The optimal VAR dispatch problem is formulated as a non-linear constrained multiobjective optimisation problem where the real power loss and the control variable adjustment costs are to be optimised simultaneously. The proposed approach handles the problem as a true multiobjective optimisation problem. A hierarchical clustering algorithm is imposed to provide the decision-maker with a representative and manageable Pareto-optimal set. Moreover, fuzzy set theory is employed to extract the best compromise solution over the trade-off curve. The results demonstrate the capabilities of the proposed approach to generate true and well-distributed Pareto-optimal solutions of the multiobjective VAR dispatch problem in one single run. In addition, the effectiveness of the proposed approach and its potential to solve the multiobjective VAR dispatch problem are confirmed.
Keywords: optimal VAR dispatch, evolutionary algorithms, multiobjective optimisation, control variable adjustment, reactive power, fuzzy sets, fuzzy logic