Reliability Assessment of an Off-Grid Hybrid Micro-Grid Power System (HMPS) for a Remote Community in Nigeria

Abstract

Power System reliability assessment is one of the most crucial mensurations to evaluate power provider services and continuous availability. Hybrid Renewable Energy Systems (HRES) are an effective means to provide off-grid electrification to the rural areas that predominantly do not have access to electricity. This paper presents the reliability performance of a typical remote Obayantor community hybrid micro-grid in Edo state, Southern Nigeria. The hybrid energy system provides power for 90 households via a combination of 300W Solar Photovoltaic (PV) Modules, 1200Ah back-up battery system, and a 65kW diesel generator. The PV modules generate power throughout the day; the back-up provides energy source in the night while the diesel generator is sparingly used only in the event of faults, maintenance, or repairs. The reliability indices calculated were Mean Time to Repair (MTTR), Mean Time Between Failure (MTBF), and Availability using the outage data obtained from the microgrid between 2015 and 2019. The results recorded showed that the micro - grid was always available due to low downtime and low frequency of outages over the five years studied. Except in 2018, when the result recorded had the highest rate of power of interruption, which gave rise to the smallest value of availability and MTBF obtained in the same year. 2015 and 2019 had the highest availability value of 99.8%, and this value showed a similar trend to MTBF with the highest value in 2015 and the minimum value in 2018.