SOLVING MULTIOBJECTIVE VOLT/VAR CONTROL PROBLEM IN DISTRIBUTION SYSTEMS BY FUZZY SET THEORY AND PARTICLE SWARM OPTIMIZATION

摘要

This work describes an optimal dispatch of three controlrndevices (i.e. under load tap changer (ULTC) of a substationrntransformer, substation capacitors, and feeder capacitors)rnfor multiobjective volt/VAr control in distribution systems.rnFive objectives of interest in the problem are energy loss,rnbus voltages, THD levels, power factor at substation andrnthe total number of switching operations of all controlrndevices. All the objectives are fuzzified using a trapezoidalrnmembership function in fuzzy set theory and are integratedrnto represent a fuzzy decision value. Based on the obtainedrnfuzzy decision value, a searching process by particlernswarm optimization (PSO) algorithm is employed to findrnthe optimal dispatch schedule that provides the bestrncompromise among all the objectives. Case study isrncarried out with a modified 29-bus distribution system ofrnProvincial Electricity Authority (PEA), Thailand to revealrnthe performance of the proposed methodology.