It adopts advanced electromagnetic design software, and meets IEC60076, GB1094, GB/T6451, GB/T252Q9-2010 standards. Without such device like conservator, air breather-., so it ensures that the transformer oil is not in contact with air, improving the anti-oxidation capacity of the transformer oil and delaying its aging. The core is made of high quality cold-rolled grain-oriented silicon steel sheet, with laminated structure miter joint, so as to reduce the no-load losses and no-load current.