RELIABILITY IMPROVEMENT IN DISTRIBUTION SYSTEM BY INJECTED DISTRIBUTED GENERATION BASED ON ZONE BRANCHES METHODOLOGY

Abstract

The aim of this paper is to reach the best balance point between the maximum reliability and minimum lost cost when injecting Distributed Generation (DG). The new Al-Kadimeya substation in Al-Kadimeya sector in Iraq – Baghdad was chosen for this research, because there is a group of four diesel generator injected in it is mesh. These DGs suffers from stop working and interruptions in the supply of energy, which causes its failure to do its task of supporting the national grid in electrical power. This substation has fifteen different feeders. Five diverse feeders were selected to inject DGs in it. The injection was in several locations on the selected five feeders sequentially. Zone branch methodology applied in analysis these feeders and the required calculations were carried out until the best site with the lowest failure rates was reached to inject these generators, which is feeder 2. The failure rates of the five feeders were reduced by 151 times, about 14%. Outages duration were reduced by five h/y, approximately 3.67%.The lost power costs for all previous test sites of injecting distributed generation were then calculated too. Then the site with the highest lost power (i.e. the one of the highest lost cost) was selected to inject the generators to it which was feeder 2 also, where the expected lost costs due to interruptions were reduced by 510,000 USD /y, about 16.4%. Results show that feeder 2 represents the best location for injection of the DGs instead of the current location on feeder 4.

Keywords

• distributed generation
• zone branch methodology (zbm)
• failure rate
• average repair time
• expected customer interruption cost (ecost)