A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School o Environment Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1998

Distribution system planning is very important for electric power utilities. The objective of distribution system planning is to assure that a growth in demand for electricity can be satisfied in an optimal way by additional distribution systems, which are both technically adequate and reasonably economical. All the alternatives in distribution system planning should be evaluated carefully. Electric utilities always need to reduce the power losses and improve voltage profiles in their distribution networks and at the same time they need minimal investment costs. To reduce the power losses and improve voltage profiles, utilities can install capacitor banks or reconductoring or add more feeders to the existing networks and they can also increase distribution voltage level. In planning, the utilities have to study their distribution networks looking into all possible alternatives and compare them by technical and economical criteria. The alternative, which meets the technical, economic and environmental criteria at minimum cost, should be selected. This thesis applies two alternatives of distribution system planning. In the first alternative, the existing voltage level is unchanged except for one feeder. This alternative requires many feeders to be added to meet the technical criteria. In the second alternative, a 22 kV distribution voltage level is proposed and fewer feeders are needed. In order to reduce power losses, a capacitor bank is applied to installed at a feeder center of gravity. In network analysis, PSSU and SLOCl computer programs have been used. The results of these alternatives have been obtained and one alternative in distribution system planning is recommended.