OPTIMISATION OF FEEDER SIZES IN A DISTRIBUTION NETWORK

Abstract

This dissertation work describes the optimization of feeder sizew in a distribution network through optimal grading of the conductor cross-sections along the feeder main and an efficient optimization procedure for parameter optimization. The distribution system planning problem has been high lighted in the introductory chapter. A brief review of the available literature on these two aspects of distribution system planning has been given in Chapter-II. The third chapter deals with the conductor gradation problem. In this chapter mathematical models to represent feeder voltage drop, feeder cost and energy loss cost are described as a function of cond_etor cross-section. The effect of growth factors such as increase in the cost of energy with time and, growth in load factor have been described. By using these models a cost function, representing an over-all cost of the feeder (consisting of capital investment and the present worth of the energy loss cost) during the feeder life is defined. Minimization of the cost function is done, subject to a voltage drop constraint. This model is appli-cable to any type of radial feeder. The results of the application of these models to a system are also included in this chapter. For parameter optimization, mathematical models to represent the various cost components, loss coefficients, substation feed area and feeder service area in terms of the variable system parameters are given in Chapter-IV. Two objective functions- one to represent the system cost as a function of substation feed area and the other to represent the substation cost as a function of the feeder service area are defined. The objective functions are mini- mized using two level optimization process to obtain the optimal substation feed area and feeder service area for a given conductor size and load density. The optimized sub-station feed area and feeder service area determine the optimal voltage regulation, number of sub'stations, number of feeder ofper substation, feeder loading, feeder main length and conductor size. The optimized parameters for a test system have been obtained and are included in this chapter. The' Chapter-V is the concluding chapter, in which the results obtained, have been diseassed. The details of the computer programs and their flow charts are given in Appendix A and D.