Oil-immersed transformers use oil as their primary insulation and cooling medium, employing methods such as self-cooling, air-cooling, water-cooling, and forced oil circulation. The main components include the core, windings, tank, conservator, breather, explosion-proof pipe (pressure relief valve), radiator, insulating bushings, tap changer, gas relay, thermometer, and oil purifier.
Due to the long-term immersion of the silicon steel sheets in the transformer, oil permeates the layers, and the elasticity of the transformer oil provides a buffering effect, resulting in lower noise levels. However, the tap changer is located inside the tank, and the contact quality during voltage adjustment is not visible from the outside. If contact is lost, the circuit is open; poor contact can easily burn out the switch under excessive load.
