Assessment Of Electric Power Distribution Feeder Reliability: (Case Study of Adama City Feeders Before and After Rehabilitation)

Abstract

A stable and reliable electric power supply system is an inevitable pre-requisite for the technological and economic growth for any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and the regulator's requirements satisfied at the lowest possible cost. It is a known that the fact around the world that 90% of the customer service interruptions is caused due to failure in the distribution system. Therefore, this thesis covered assessment of electric power distribution feeder reliability: case study of Adama city feeders before and after rehabilitation. Based on data taken for three years and nine month from 2009 up to 2012 E.c the maximum interruption fault types are operational fault, permanent short circuit fault and permanent earthling fault. The minimum faults are happened due to temporary short circuit fault and temporary earthling fault. to evaluate of distribution feeder’s interruption reliability indices before and after rehabilitated Adama distribution network by taking eight months of before and after rehabilitated network. Before rehabilitation total outage duration system average interruption duration index is 12506.18-minute, system average interruption frequency index is 91 times, the customer average duration customer average interruption duration index is 137.42 and unsold electricity is 38,012,835.00 birr This is too far from the after rehabilitated feeders outages after rehabilitation the Reliability of the 15kV system could be further improved by the installed eight switching stations, auto recloser, and rehabilitated fifty five transformers consider load and low voltage installed by insulated wire and constructed a concrete pole up to customer service drop. Additionally, fifty five transformers connected with installed SCADA station, after rehabilitated the reliability index of system average interruption duration index is 8163.22, system average interruption frequency index is 49 and customer average interruption duration of index is 166.59 and unsold electric city is 25,986,615.00 birr base on this value after rehabilitated is more reliable than before rehabilitated