Power distribution system reliability analysis and network reconfiguration by using PSO algorithm, Case of Wolaita Sodo town distribution system

Abstract

The reliability analysis of a power distribution system is highly important for both customers and the utility to ensure supply continuity and improved revenue. With the growing demand for dependable power supply, it is crucial for utilities to dedicate efforts towards guaranteeing an uninterrupted power supply to meet customer needs. However, the frequent occurrence of power interruptions and the prolonged outage duration pose significant challenges to the power distribution systems, especially in Wolaita Sodo town, thus impacting the daily operations of customers. The three-year interruption data collected from Wolaita Sodo district revealed that the system average interruption duration index and system average interruption frequency index for the Wolaita Sodo town feeder are not within the EEU industry standard of 25hrs and 20 per year, respectively. According to the collected interruption data, the system average interruption duration index and system average interruption frequency index values are found as 573.59hrs and 427 per year in 2023, respectively. The unserved energy (EENS) is found to be about 1835.5MWh. This study focuses on improving the distribution system’s reliability in Wolaita Sodo town through distribution network reconfiguration (DNR) based on automatic re-closers (AR) integration. The particle swarm optimization (PSO) in MATLAB is used to find the optimal locations of auto-reclosers (AR). The reliability indices such as system interruption frequency and duration and energy not served, are assessed using the ETAP simulation package.   The study examined the reliability metrics by incorporating five auto-re-closure units with the help of particle swarm optimization for optimal location. The analysis revealed that with the integration of five auto re-closure units, the system interruption frequency index is enhanced from 427 to 4 and the system interruption duration index is decreased from 573.59hr to around 54.03hr. Moreover, it was revealed from the results that the expected energy not served is reduced from 1835.5MWh to about 140.38 MWh per year, and the cost of unserved energy decreased from 992,454.85Birr to about 75,903.46Birr.

Keywords: Automatic re-closer, Distribution network reconfiguration, Failure analysis, PSO, Reliability index