Oil Immersed Distribution Transformer

Core

The core is made of high-permeability grain-oriented cold-rolled silicon steel. It adopts a new type of core with fully mitered stepped joints. The core limb has a multi-step circular cross-section, and the yoke and core have equal cross-sections.

Windings

The windings adopt corrugated oil ducts and a non-varnishing process, and are bound with tightening straps. All windings are concentric coils. The high-voltage winding has taps corresponding to the required tap voltages, which are led to the tap changer. The tap changer is installed on the tank cover, and the tap voltage can only be changed after the power supply is disconnected.

Safety Protection Devices

Transformers from 30 to 2000kVA are equipped with a pressure relief valve.

A gas relay with alarm and trip terminals can be installed upon user request.

Oil Temperature Measuring Device

All transformers are provided with a socket for a glass thermometer, which is located on the top of the tank and extends into the oil by 120 ± 10 mm.

Transformers from 1000 to 2000kVA are equipped with an outdoor signal thermometer.

Transformer Tank

The transformer tank is composed of corrugated walls, and the surface is treated with sandblasting, spraying, and epoxy coating. The corrugated fins not only provide cooling but also have a "breathing" function. The elasticity of the corrugated fins compensates for the volume change of the transformer oil caused by temperature fluctuations. Therefore, the fully sealed transformer has no conservator, reducing the overall height of the transformer.

The transformer is sealed using a vacuum oil filling process, which completely removes moisture from the transformer and prevents the transformer oil from coming into contact with air. This effectively prevents oxygen and moisture entering the transformer, which would otherwise lead to degradation of insulation performance and aging of the transformer oil. As a result, regular oil sampling testing is not required.