Comparison of two 400 kVA dry and oil type transformers with the same loss, performance and features in terms of production costs

Distribution transformers are considered as one of the most important parts of an electrical distribution network. We can classify transformers in different ways from the perspective of production method, insulation, cooling, power, function etc. Transformer selection is made by considering different factors. In terms of insulation and cooling system, transformers are divided into two groups as oil immersed type and dry type. In dry type transformers, insulation is made with special epoxy resins and air. Oil and air undertake this task in oil type transformers. Dry type transformers are easier to maintain and repair and can be done on site. It is less harmful to the environment, the probability of causing a fire is very low. Heavy maintenance of oil-type transformers should be done in the factory, because of the oil used, it causes more damage to the environment and is susceptible to fire and explosion. Dry type transformers are more expensive than oil type transformers. In this paper, the authors tried to compare the production cost of two 400 kVA oil and dry type transformers with the same characteristics like input/output or losses and performance. First, the optimal design of both transformers was carried out with the program. The transformers were manufactured at the factory according to the optimal design. After production was completed, both transformers were subjected to routine tests to see the performance of the two transformers. Then production cost of the two transformers was compared. According to our calculations, Dry type Transformer cost about 47.7% higher than oil immersed type. The production of dry type transformers is more sensitive. The raw material used is more and hence the price is higher, but in many places it is replacing oil type transformers. The factory where we work is located in Ankara. We will have to pay attention to this in terms of raw material prices and the average of the first half of 2021 is taken.