The study examined the reliability of the power supply on Igwuruta distribution network. The network was modeled using the Newton-Raphson power flow analysis method in the Electrical Transient Analyzer Program (ETAP19.1) software. The frequency of interruption and duration of interruption were calculated using data gotten from Igwuruta Injection substation. The system’s reliability for a single disturbance was assessed. The result obtained from base case simulation shows that the fault resulting in the least availability of the substation to serve its customers is earth fault 72.8% followed by over current fault 83.1% and planned outage 95.8%. The value shows that the substation was available for an approximate average of 93% in a year. Therefore, is considered to be low when compared to the when compared to the IEEE ASAI standard of 99.9% for distribution substation availability. However, with the incorporation of a solar-type renewable energy DG on the network, the availability of the substation to serve its customers was improved to 97.5% for earth fault, followed by over current fault 98.6% and planned outage 99.5%. The availability of the substation to serve its customers was calculated as 0.9932 which indicates the substation was 99% available in a year. The availability of the substation met the IEEE ASAI standard of 99.9% for distribution substation availability. An additional 2x 3.5MVA transformer was added to the renewable energy DG to step up the voltage to 11kV and also serve its customers when there is a power outage from the grid.