Power losses on distribution network: estimation using simulated annealing

Knowledge about bus voltages and power losses in primary distribution feeders is important to system planning and operation. However, it is not a simple task to obtain these informations because, usually, measurements are only taken in the beginning of the feeder. Generally, a load flow program is used to calculate bus voltages and power losses. As the real demand in each bus is unknown, it is supposed that their load curves are similar to the load curve of the whole feeder, determined from measurements at the substation (usual method) (B.A. Souza et al., 2004). Another solution is to use typical load curves in substitution to the proper load curve of each bus (H.N. Alves et al., 2004). At any rate, the results of the load flow program can be too unrealistic. This paper presents an alternative procedure to estimate bus voltages and power losses on radial distribution feeders, which is based on the optimization algorithm called simulated annealing. The proposed method has been applied to the IEEE 13, 34 and 123 test feeders and the results has showed that the total power losses estimated are close to the actual losses. The results of a comparative study between the proposed method and the usual method are also presented