The Determination of the Convenient Number of Transformers on Electricity Distribution Systems

In this study, a cost analysis was performed for an energy distribution system including the initial investment costs, power loss, maintenance-repairment expenses in time and the benefit of the system for various power demands and lengths of power line. Enough and necessary number of the identical transformers was investigates to reach the maximum profit. Hence, the maximum benefit and the shortest depreciation time were taken into account. Swallow type cables are used as small cross section cables and Hawk type cables with large cross sections. That thick section cables are effective for energy loss, but in reality the enormous cost is caused by the transformer itself, depending on its capacity. A multi-objective optimization problem was solved by means of the maximum value of the ratio of the maximum benefit or the shortest depreciation time instead of taking them solely.