Biru, Getachew(PhD)Birhan, Shumye2018-07-092023-11-282018-07-092023-11-282017-03http://etd.aau.edu.et/handle/12345678/7377Power distribution system development initially was conceived in the form of DC distribution system. But, due to different drawback of this system and the invention of transformer, it was shifted to AC distribution system. As a result, the manufacturer created AC powered loads to the customers to meet AC generation systems. AC system dominated the market for a long time. Lately, the developments achieved in power electronics area led to further studies in direct current power systems.This research work presents the development and comparative study of DC distribution systems by taking 132/15kV, 20MVA, 50Hz distribution substation system to be extended to MVDC as study of the research. The specific objective of the study is to develop alternative DC distribution system and make a comparative analysis of MVAC and MVDC in terms of power loss, material cost, system efficiency and energy loss cost. carrying capacity of AC and DC distribution system, the total power loss, equipment cost and the system effiecncy was computed and compared each other. Finally, three DC distribution scenarios were developed and evaluated in terms of power loss, efficiency and cost. Each scenarios were compared not only with the traditional AC system but also with each other. The existing AC distribution evaluation system results in 1989.7 KW power loss, 348,595 USD energy loss cost, 3,094,622 USD materials cost and 90 % overall efficiency. In DC distribution, Scenario A evaluation results in 1610 KW power loss, 282,072 USD of energy loss cost, 2,433,290 USD of materials cost and 91.9 % of overall efficiency. Scenario B evaluation results in 2011.5 KW of power loss, 352,418 USD of energy loss cost, 2,989,308 USD of materials cost and 89.9 % of overall efficiency. Scenario C, The DC structure which consists of DC/AC inverter with its system efficeincy 92.6 %, power loss 1486.5 kw, the energy loss cost of 260,438 USD and equipment cost of 2,989,308 USD were achieved in which it was much significantly less than AC distribution system. As the quantitative results showed, around 500 KW power saving and more than 0.2 million USD momentarily saving have been possibly achieved by using scenario C of DC distribution system as compared to the existing AC distribution system. Key word: Distribution, Direct Current, Alternative Current, Power loss, Transformer, Converter, Rectifier, Inverter and Feasibility study.enDistributionDirect CurrentAlternative CurrentPower LossTransformerConverterRectifierInverter and Feasibility StudyThesis