Calculating electric loss and planning a strategic plan in loss reduction is a main activity in the asset management of an electric distribution network. In usual methods, offloss calculation load flow as well as placed meters in different parts of the network are used. However, electric loss in distribution network is estimated rather than calculated due to reasons, such as the absence of network databases or load meters and computation burden in large-scale distribution networks. This paper proposes a new heuristic method for loss estimation of the low-voltage sector of a large-scale distribution network faced by a scarcity of network data. This method uses load characteristics similarity for feeder clustering. Extracting a loss model for each cluster subject to a small fraction of network data is the main step followed in this paper. Finally, the extracted loss model would be used as an instrument to estimate the copper loss of the considered network. Moreover, a computer program is developed in order to evaluate the accuracy of the method. The proposed method is employed to estimate copper losses of Gilan distribution network in Iran.
