Abstract:
The majority of outage events experienced by customers are due to electrical distribution
failures. Increasing distribution network reliability is a necessity in order to reduce interruption
events. Unreliable power distribution reduces user power consumption, affects daily activity and
drags modern life style. Basically, Power Distribution Reliability has been a major challenge in
Bedele city. It has incurred cost on customers and lowered product quality. In Bedele city and
surround, Customers have faced frequent interruption and utility has taken long time to alleviate
it. Hence, it has to get amicable solution. Thus, the objective of the study is to assess the
reliability of the current distribution system and suggest solutions of reliability improvement.
Bedelepower distribution system of south west region, which has high rate of interruption, is
selected as case study area. Bedele city and surrounds feeder lines reliability is assessed based on
two years datafrom Ethiopian electric power (EEP) of south west region. To limit the scope of
the study, Bedele city and Brewery Factory line from Bedele substation is chosen for reliability
improvement measures. Bedele cityFeeder has SAIDI of 710 hour per customer per year and
SAIFI of 617 Interruption per customer per year. And Bedele Brewery factory has SAIDI of 320
hour per customer per year and SAIFI of 272 Interruption per customer per year. The reliability
index values of both feeders are not within the ranges of bench marks of best practices and
Ethiopia‟s reliability requirement.
Therefore, the appropriate components of Distribution system reliability improvement protection
devices are selected. Different power distribution system cases are analyzed by considering
feeder segmentation and auto restoration improves distribution reliability. Each cases payback
period and reliability performance of distribution system evaluated. The reliability assessment of
power distribution system with protection device is simulated using the ETAP software. The
simulation of the power distribution models shows that the application of reclosers can improve
the reliability of the overall system from 47% to 83%. Finally, best scenario is selected and
proposed as a solution to improve Distribution reliability of the two feeders for implementation
