Oil Tank

The core functions of a transformer tank can be summarized as "containment, heat dissipation, protection, and support."

Containment and Insulation: The tank acts as the transformer's "shell," holding the transformer oil inside, with the iron core and windings completely immersed. The transformer oil plays a crucial insulating role, ensuring sufficient electrical strength between live parts and from live parts to ground.

Heat Dissipation and Cooling: During operation, the iron core and windings generate significant heat. This heat is transferred to the transformer oil. The hot oil rises and dissipates heat into the air through the tank walls or externally attached radiators (such as panel-type radiators or coolers). The cooled oil then returns to the bottom of the tank, creating a circulation loop that effectively controls the transformer's temperature rise.

Protection: As a sealed enclosure, the tank effectively isolates internal components from external moisture, oxygen, and impurities, preventing the deterioration of transformer oil and protecting internal parts from environmental influences. For on-load tap-changers, a separate on-load tap-changer tank is often used to house the diverter switch exclusively, as the arcing generated during its operation can accelerate oil degradation.

Mechanical Support: The tank serves as the framework for mounting external transformer accessories. Components like high-voltage and low-voltage bushings, conservators (oil conservators), gas relays, radiators, and various valves are all fixed onto the tank. The tank bottom is typically equipped with a base featuring pulling and towing attachments for ease of transport and installation.