Determination of capitalization values for no load losses and load losses of distribution transformers

Abstract

Transformers are one of the better efficient components in the electricity distribution network. Basically substation transformers and distribution transformers are currently used in the electricity distribution network in Sri Lanka. Evaluation on the purchasing price of the transformer is not enough during the purchasing process. There are losses due to no load losses and load losses in the transformer during life which is about 30-35 years. Therefore, transformer purchaser must be look at total life time cost of the transformer during the purchasing process. Traditionally, this evaluation is done based on Total Owning Cost (TOC). Currently in Sri Lanka, CEB does not use competitive bidding process in purchasing of distribution transformers. And also, CEB has not defined capitalization values for distribution transformers to evaluate them based on TOC. Main objective of this research is to set up a methodology to calculate capitalization values for distribution transforms in Sri Lanka using IEEE loss evaluation guide. Capitalization values for distribution transformers depend on capacity cost and energy cost, economic considerations and load profile of distribution transformers. In this research, capitalization values are calculated for three different load profiles, i.e. rural, semi urban and urban. A computer based methodology was developed to calculate capitalization values as an outcome of this research. In future, CEB can purchase distribution transformers by using these capitalization values for different applications, i.e. rural electrification, loss reduction in urban cities, augmentation of distribution transformers, etc. And also, any other utility can use computer based model to calculate capitalization values for distribution transformers at any given time corresponding to a set of economic and other parameters.