Performance Assessment of Power Distribution System: (A Case of Rehabilitated Power Distribution System of Adama Town)

Abstract

A stable and reliable electric power supply system is a predictable prerequisite for the technological, economic and political growth of any nation. Thus, utilities must struggle to advance their system for delivering a stable and reliable electric power supply system to customers. According to power grid operation and interruption data recorded at utility, currently most power outage suffered by customers service interruption are caused due to failure in power distribution system, wherein power interruption caused by medium and low voltage distribution networks disturbance approximately account for 90% of the total power outage. In addition, according to several years statistical analysis of power supply reliability, currently 70% of reasons for power outages lie in network transformation, power expansion and the planned maintenance of distribution networks. Therefore, it is very important to do worth considering reliability performance assessment in power distribution system. This thesis work has been conducted on performance assessment of power distribution system focused on rehabilitated power distribution system of Adama Town. The study has been conducted to assess the reliability of power distribution system performance in terms of power interruption by identifying the most outstanding fault factors and root causes, and recommend a solution on the outstanding fault factors and root causes that made frequent power interruption in Adama Town distribution system. The assessment analysis has been done on eleven 15kV feeder lines and ten fault factors to predict reliability analysis for the future. The interruption frequency data of years 2009-2011 (EC) has been used as a base year for analysis. Based on interruption frequency data of the base years analysis and questionnaire on the root causes of fault factors that made frequent power interruptions, out of the ten fault factors the city feeder lines experienced highest number of outages due to by OP with 42.45%, DPSC with 21.09% and DPEF with 19.45% fault factors of the overall disturbances, and root causes for fault factors are mainly planed intentional interruptions, windy condition, tree contact, usage of improper devices, human errors and others. Finally, it has been identified that the three most significant disturbances (OP + DPSC + DPEF) that made frequent power interruption in Adama distribution system account for about 82.99% of the frequency of disturbances against customers of the EEU.