Moisture in the water of oil immersed transformer will do great harm to the electrical and physical and chemical properties of insulating medium. The existence of moisture will destroy the insulation strength of transformer oil, promote the corrosion of organic acids to copper, iron and other metals, and catalyze the oxidation of transformer oil, resulting in the aging rate of transformer oil increasing by 2-4 times compared with that when it is dry. Even permanent damage to the paper insulation. If the water and moisture of the transformer are not treated in time, it will even lead to the breakdown of the coil to the ground or the turn to turn short circuit of the coil, resulting in equipment damage.
Water ingress and moisture of oil immersed transformer
During the operation of oil immersed transformer, if it is found that the transformer is affected by water and moisture, it shall be dried in time to avoid damage to the transformer equipment and affecting the safe operation of power system. In addition, prevention work shall be done to avoid water ingress and moisture of oil immersed transformer. Precautions are as follows:
1. Before changing or adding oil to the transformer, the oil shall be tested to prevent water from entering the oil due to improper storage during storage.
2. Before refueling the transformer, drain a small amount of oil stored in the conservator. At the same time, align the oiler with the refueling port, and then add it slowly to ensure that the oil level is between 1 / 4-3 / 4 of the oil standard.
3. Refueling or oil change shall be carried out at noon on a dry sunny day, and the oil shall be filled in a clean and dry container. Never refuel the transformer in rainy weather.
4. Prevent transformer oil shortage. When the oil level of the transformer drops below the transformer shell, the contact area between oil and air increases, and the transformer oil is easy to absorb moisture in the air.
5. For large capacity transformers, respirators shall be used, and hygroscopic agents shall be used to prevent moisture accumulation. For small capacity transformers, the height of the oil pipe connecting the body and the conservator at the oil pipe orifice in the conservator should be appropriately increased to prevent moisture from entering the transformer body.
In short, during the operation of oil immersed transformer, we must do a good job in prevention to avoid water ingress and moisture of oil immersed transformer, so as to ensure the safe operation of power system.