Influence of Insulating Cylinder on Electric Field Inside Cast-Resin Dry-Type Power Transformer

Insulating cylinders are important components in dry-type transformers. Placing an insulating cylinder in the main air channel can effectively reduce insulation distance between LV and HV winding. Therefore, to study the influence of insulating cylinders on the distribution of electric field in transformers is necessary. This paper built a CRDT cross-sectional model and the electric field was calculated by using finite element software COMSOL. This paper focused on the influence of the position, quantity, and relative permittivity of insulating cylinders on the electric field of transformers, especially on the electric field of HV winding. In addition, this paper also studied the influence of insulating cylinders on the electric field of the main air channel. The results show that, the insulating cylinders will increase the electric field strength of the transformer. The results also show that reducing the relative permittivity of the insulating cylinders can reduce the above impact.