How Oil Immersed Transformers Work

The operating voltage of power transformers should generally not be higher than 105% of the operating tap voltage, and should not exceed the maximum operating voltage of the system. For special use, it is allowed to operate at a rated voltage not exceeding 110%.
The top oil temperature of oil-immersed transformers should not exceed the operating regulations or the manufacturer's regulations. For transformers with forced oil circulation water cooling, the top oil temperature should generally not exceed 700℃.
Transformers with forced oil circulation cooling should be able to control the cooler to switch in accordance with temperature and (or) load.
Transformers put into operation should frequently monitor the indications of the instrument to keep abreast of the transformer operation. If defects or abnormal phenomena are found, measures should be taken to eliminate them in time. If they cannot be eliminated at the time, monitoring must be strengthened to prevent the accident from expanding. And determine countermeasures as soon as possible.
1. Water supply method of transformer cooling water system
When the transformer is running under load, the cooling water is generally taken from the technical water supply pipe of the unit unit. When the transformer is running under no-load, the cooling water is generally taken from the public water supply main of the power station, and the no-load cooling water pump is pressurized to supply water to the transformer.
2. Transformer cooling water system drainage method
Under normal circumstances, the cooling water of the transformer when it is unloaded and loaded is discharged to the tail water pipe of the unit through the drainage main pipe of the unit technical water supply system. A connecting valve is installed between the drainage pipes of each transformer. The connecting valve is normally closed. When the tail water pipe of the unit is required to be emptied and the transformer is still in narrow load operation, the connecting valve between this transformer and the adjacent transformer can be opened to discharge the unloaded cooling water to the tail water pipes of other units.