This paper analyzes the harm and cause of unbalance of three-phase load of distribution transformer, and puts forward some measures to solve the unbalance.

The main materials of the transformer body include magnetic circuit materials, circuit materials, insulating materials, structural materials, etc.

Box transformer is the integration of high and low voltage primary equipment, transformer, secondary equipment in the factory in a double layer, sealed, anticorrosive, movable outdoor box.
Box type substation, also known as preinstalled substation or preinstalled substation. Is a kind of high voltage switch equipment, distribution transformers and low voltage power distribution equipment, according to the wiring scheme must be arranged in one of the factory indoor, outdoor compact type distribution equipment, the step-down transformer, low voltage power distribution, and other functions organically combined together, installed in a moisture, rust, dust, rat, fire prevention, guard against theft, heat insulation, fully enclosed, movable steel box, Especially suitable for urban network construction and transformation, it is a new substation after the rise of civil substation. Box-type substation is suitable for mines, factories, oil and gas fields and wind power stations. It replaces the original civil power distribution room and power distribution station and becomes a new complete set of transformer and distribution devices.