A Distribution Transformer Comprehensive Optimal Planning and Sizing Method

A significant part of the power system losses are due to the distribution transformers energy losses. The high share of these transformers to the electric energy losses of the country’s power network in each year, contribute to an important share in the loss of national yearly resources and country budget. On the other hand due to the high rate of yearly increase in electric energy usage in the country, optimal distribution transformer planning and sizing has a very important role in saving these losses over the future years. To address these concerns, it is required for the distribution companies to help optimize utilization of electric energy sources, which results in increase of distribution companies’ benefits. This paper introduces a method for proper, optimal and intelligent selection of distribution transformers power rating and efficiency class. This will increase the distribution companies’ benefits through reduction in the respected energy losses. The previously used methods in the country, didn’t model the replacement of a distribution transformer with another one of different rating. This paper models different scenarios, realizing yearly future load growth in a region, besides possibility of stablishing a new substation to develop a comprehensive algorithm for distribution transformer planning and its replacement during its life. Final target of this work is the development of a code for optimized planning of a new distribution substation. The proposed algorithm prepared for Tehran’s Large Electricity Distribution Company and demonstrated promising results.

Keywords:

distribution transformer , owning cost , optimum selection