Insulation and Withstand Voltage Performance of Dry Type Transformer
The insulation of the dry type transformer is not composed of a single dielectric, but a combination of various dielectric. For the single multilayer insulation structure, the ideal electric field distribution is that the field strength under the dielectric of each layer is proportional to the dielectric strength of the medium. The voltage that can be tolerated is the highest.
From the comparison of the relative dielectric constant s values of the following insulating materials, the C value of NOMEX paper is lower than that of epoxy resin, and is closer to air. When the NOMEX paper is used, the electric field distribution between the insulator and the surrounding air medium will be more uniform, and
its production process is simple. It can effectively reduce the partial discharge and slow the insulation aging. When the epoxy resin insulation is used, the high true space can not be used because the pouring process is required (because the high temperature and vacuum are used together. The use of epoxy resin will boil), so
there is still thin air in the pouring process, and the process is complex, the execution is not strict, and when the treatment of no resin appears to be inverted, there will be bubbles in the product. These fine air gaps will become the phenomenon that the local epoxy resin insulation can easily crack after a long time operation, which is the biggest disadvantage of the epoxy resin pouring type dry type transformer.