AN ASSESSMENT OF HARAMAYA UNIVERSITY DISTRIBUTION SYSTEM RELIABILITY

Abstract

Providing quality and reliable electricity to customers plays an important role in every country's economy, politics, and technology. In Ethiopia, delivering the reliable electric power to the customers is the role of Ethiopian Electric Utility. However, for Haramaya University, power interruptions are a serious problem. This thesis assesses the reliability of Haramaya University's (HU) power distribution system (DS) and suggests improvement techniques. In this thesis, analytical method was used to evaluate the reliability performance of the HU power distribution system. According to the findings, the existing Haramaya University distribution network has serious reliability issues, and the root causes of power outages are overload, tree contact, wind, aging of poles and equipment, cable failure, maintenance and operational practices. The one line diagram of Haramaya University's existing and future distribution systems was modeled without and with diesel generators, fuses, reclosers, and solar distributed generators using ETAP 19.0.1 software and simulated differently in six cases. The results showed that, the reliability indices of existing system are beyond the Ethiopian standards and among all the cases of reliability improvement, the values of reliability indices were significantly enhanced in case 2 (underground ring distribution network). The System Average Interruption Frequency Index (SAIFI) was reduced from 196.38 to 1.1802 interruptions per customer per year; the System Average Interruption Duration Index (SAIDI) was reduced from 277.78 to 20.77 hours per customer per year; and the Average Service Availability Index (ASAI) increased from 96.83% to 99.76%. Because of power interruptions in Haramaya University's existing distribution system for the last two years, the estimated revenue loss of Ethiopian Electric Utility (EEU) was around 2,585,743.99ETB/year and HU lost between 1,688,046.05 to 5,961837.61 ETB/year. In case 2 the utility can save revenue of 2,239,549.9ETB/year and HU can save 5,762,746.38ETB/year. The installation of fuses and reclosers in distribution lines, the integration of solar distributed generators, and the conversion of an overhead radial network to an underground ring network can all improve distribution system reliability. Replacing old equipment and tree trimming will be an alternative solution for reliability improvement of the existing distribution system until the underground ring distribution system is completed.