Efficiency and losses evaluation in electric transformers

The efficiency rate is one of the basic parameters that a transformer must comply in order to be sold in the market. However, some electric companies decide not to buy solely on the final price but on the Total Owing Cost (TOC). This means, the additional cost the company will have to pay besides the transformer cost due to operational losses throughout its lifespan. Therefore transformers in this market should not only be design to meet efficiency regulations but they need to be design to have the lowest possible losses without significantly increasing the transformer cost. Techniques to increase the efficiency in a design in order to lower the cost of losses are discussed.