ENERGY-LOSS REDUCTION BY CRITICAL SWITCHES

This paper presents a systematic method to derive an optimal switching plan to achieve energy loss minimization for short term and long term operation of distribution systems. The short term optimal switching c riterion is developed by binary integer programming with branch and bo und technique. A overall optimization problem is formulated for the op timal switching operation. It is further divided into several subprobl ems to find the largest energy loss reduction among all possible switc hing operation between two feeders. A quick method is applied to estim ate the largest loss reduction for each feeder-pairs in the distributi on system during short term switching operation. In this paper, the co mposite load profile of each feeder is derived by the field test over one year time period. According to the typical load patterns of each c ustomer type, the hourly loading of each service section can be simula ted more accurately. After determining the hourly optimal network conf iguration by taking into account the typical daily load patterns for a ll the distribution feeders, the long term optimal switching criterion for each season is derived and the corresponding critical switches, w hich should be operated for energy loss reduction as season changed fr om summer to winter and vice versa, are also determined. During the co mputer simulation, the installation and operation cost of sectionalizi ng switches are included in the objective function as actual cost so t hat the results obtained will be more practical. A practical Taipower distribution system is selected for computer simulation to demonstrate the efficiency and practicality of the proposed method to reduce the energy loss by operating the critical switches derived.