Oil conservator of oil immersed power transformer is mainly responsible for oil supplement and oil storage of transformer. It is installed at the highest oil level of the transformer, mainly including the conservator body, rubber air bag, oil level indicator, conservator body and rubber capsule passing through the pipeline. The conservator body includes oil injection valve, oil drain valve, exhaust valve and sampling valve; When the oil immersed power transformer rises, the insulating oil expands to become part of the oil tank. The insulating oil flows into the conservator, and the air occupied by the conservator is discharged through the air pipe and respirator. When the load drops, the transformer temperature drops, the density of insulating oil increases, and part of the insulating oil in the oil pad will flow to the oil tank for supplement.

The oil level indicator of oil immersed power transformer is usually a disc oil level indicator, which mainly reflects the oil level on the oil pad. When the oil in the conservator of oil immersed power transformer changes, the float in the conservator will move up and down with the change of oil level, and the connecting rod of the float will drive the gear for oil level rotation. Diameter of the rotor outside the conservator. The pointer connected to the stator magnet (permanent magnet) rotates at the corresponding angle through the rotation of the rotor magnet, and the low oil level alarm is reflected by the electric contact. The oil level indicator has a total of 10 scales to reflect the oil level in the oil pad. When the oil level indicator indicates 0, the main transformer sends out a low oil level alarm signal.