Energy loss minimization with open unified power quality conditioner placement in radial distribution networks using particle swarm optimization

Abstract

This paper presents a planning approach for the integration of open unified power quality conditioner (UPQC-O) in a distribution network to improve its power loss and power quality (PQ). In UPQC-O model, the series and shunt inverters are not connected to a common DC-link. The shunt inverter is used to eliminate the harmonics created by the load and to provide reactive power compensation. The series inverter is used for dual-purpose, i.e., for the protection of all its downstream loads from voltage sag, and to provide reactive power compensation in healthy condition. The objective function is formulated as the minimization of energy loss under the voltage, thermal overloading, and the desirable PQ constraints so as to determine the location(s) and size(s) of these two inverters. The particle swarm optimization (PSO) is used as the solution strategy. The UPQC-O model is incorporated into the forward-backward sweep load flow algorithm, which is used as the support subroutine for the PSO-based planning algorithm. The results show that the optimal placement of the UPQC-O provides significant power loss reduction, bus voltage improvement, and better PQ.