A Method for Estimating Technical Losses in Primary Feeder Conductors

Abstract

One of the engineers’ concerns is the loss of energy in the electric power system. Actually, most of the energy losses occur in the distribution system, i.e., about 4-8%. Therefore, efforts should be made in order to improve the performance of the distribution networks. Evaluating losses in the distribution networks should be done in order to reduce losses. The problem is that there are many nodes, several lateral feeders, and the un-uniform current flowing in the feeder so that calculating the losses becomes very difficult. In addition, the big distribution system has so many feeders, generally more than 1000 feeders, with various types. Thus, the calculation of the losses in the distribution system will face very complex and large-scale problems. Therefore, calculating losses for large scale distributed systems that use load flow or measurement methods is not possible. This paper proposes an effective method that uses a lump load model for technical losses in distribution systems. By approaching, the current is proportional to power, the input current into the feeder can be distributed to each lateral feeder. Thus, the current flow in each segment of the feeder can be determined. For typical feeder with the load currents changed linearly by linearity factor, then-current flows of each segment feeder can be easily determined as c function. This function is created as a calculation model of losses with a clear derivative of the mathematical formulations. The results of numerical studies show that this method is accurate enough with the error of 1.26% when compared to the load flow method using an 8-node feeder. The calculation result is based on the IEEE 13-node test feeder; its loss is smaller than 3.86% compared to the load flow method.