GA-Based Reliability Enhancement in Distribution Systems Through Sagged Bus Numbers Reduction by Optimal Placement of Unified Series-Shunt Compensator

Abstract

This paper presents a new method to reliability improvement of distribution system by optimal sizing and placement of unified series -shunt compensator (USSC).The GA based approach is used to solve the USSC optimization problem with considering capital cost of USSC installation and interruption costs due to interruption of loads in sensitive point. In this paper using ETAP software, the worst point that if three phase fault occur, therefore leads to the propagation of voltage sags to most number of system buses is investigated and located. Simulation results show that the proposed method is efficient and feasible for improving the system reliability level by reducing the number of sagged bus and load outages and momentary interruptions. Finally in this paper, after optimal location of USSC, the reliability improvement is investigated through expected energy not supplied (EENS) index, average system interruption frequency index (ASIFI) and the momentary average interruption frequency index (MAIFI).