Reliability Evaluation And Design Improvement Of Power Distribution System: Case Study On Hossana Distribution System

Abstract

Most of the customer interruptions occurred due to failures in the distribution system as a result of faults on the radial distribution feeder lines and some other factors like windy rain, animal contacts and tree branch intrusion. Unreliable power distribution system was main problem in Hossana that reduced user power consumption and affected daily activity. In this thesis work evaluation of the reliability for the Hossana distribution system was done and design solution was suggested. In this thesis the reliability evaluation for the Hossana 15 kV distribution outgoing feeders using both analytical and time sequential Monte Carlo simulation methods is done. Thus, the values for SAIFI (interruption/year), SAIDI (hours/year), CAIDI (hours/interruption), ASAI (%), EENS (MWh) and Cost of EENS (USD) respectively are 168, 395.84, 2.36, 95.48, 8740.15 and 8930150.40 in the year 2013. The ASAI value of Addis Ababa distribution was 99.425% in the year 2014 whereas it was 95.29% for Hossana city. The deviation from Addis distribution system is 4.135% deviation from the standard ranges for example from American power distribution system by 4.709% in the 2014. The customers lost electricity for about 413 hours per year in 2014. Thus, Hossana distribution system is less reliable. Feeder Reconfiguration using ETAP 12.6 software is done to minimize the outage duration of the feeder, improve the performance of distribution system and to minimize power loss on the primary feeder. As a result of FR, the power loss was minimized by about 22.85%.