The oil in the transformer mainly plays the role of heat dissipation and cooling during operation; it plays the role of insulation and insulation maintenance for the windings (to maintain a good insulation state); the oil plays the role of arc suppression at the high-voltage lead wire and the contact point of the tap changer to prevent corona and arc generation of discharge.
(1) Increase the insulation strength of each component in the transformer. The oil of the transformer has good insulation strength and fluidity. It can fill all parts and any space of the transformer, and discharge the air, avoiding the parts and the air contact with moisture, affecting the insulation strength, and making the winding and the winding, the winding and the iron core. Between the windings and the tank shell to maintain good insulation.
(2) Transformer oil cools between the iron core and the windings of the transformer. During the operation of the transformer, the temperature of the oil near the winding and the iron core rises after being heated, the volume expands, and the specific gravity decreases and rises. After cooling by the cooling device, it enters the bottom of the transformer oil tank to form the oil circulation. During the cycle, heat is dissipated to the cooling unit.
(3) Transformer oil can maintain the original chemical and physical properties of insulators (such as wood, etc.), and make metals (such as steel, etc.) play a role in anti-corrosion.
In the maintenance of large-scale transformers, the following tests are required for transformer oil: transformer oil dielectric strength tester (automatic oil tester); transformer oil acid value tester (transformer oil PH value detector) and other related items.