Initial transformer sizing for single-phase residential load

A method for determining the correct economic size of distribution transformers using end-use appliance load profiles and the ANSI/IEEE Standard C57.91-1981 thermal model is described. The goal of this method is to minimize the cost of serving residential customers with electric power while maintaining high power quality and reliability. The three steps in determining the proper transformer size are given. Although applied only to single family and multifamily residential loads, the method can be extended to other types of load such as commercial or industrial