Abstract: At present, large-capacity distribution transformers and new energy transformers are widely used, the low-voltage lead wire used in this transformer need to occupy a larger fuel tank space. A new type of low voltage lead wire structure can effectively reduce the size of fuel tank and has been applied in pilot. After studying the magnetic circuit of the clamp with the new lead structure, it is found that although the overall magnetic motive force of the clamp is zero, there are local magnetic flux changes of the clamp. The results show that the local magnetic induction intensity of the low voltage clamp is higher and the loss of the clamp is increased obviously. It shows that the new lead wire structure has defects and local overheating risk. The load loss of the actual case is measured to verify the accuracy of the simulation results.

Key words: transformer, low voltage lead wire, magnetic circuit, loss