During the Qingming Festival, there are heavy rains, and the transformer is flooded and dampened. How to prevent it?


Release time:

2023-04-05

"It rains heavily during the Qingming Festival, and pedestrians on the road feel like dying." The continuous drizzle is one of the characteristics of Qingming Festival. The arrival of spring rain nourishes the growth of vegetation and stimulates vitality.

"It rains heavily during the Qingming Festival, and pedestrians on the road feel like dying." The continuous drizzle is one of the characteristics of Qingming Festival. The arrival of spring rain nourishes the growth of vegetation and stimulates vitality.

However, rainy weather is not a particularly ideal operating environment for electrical equipment such as transformers. After moisture enters the transformer, it will cause the insulation resistance of the winding to drop, breakdown and other problems. In severe cases, it will burn the transformer and cause an electrical fire. Usually, power units will conduct spring inspection activities in spring, and whether the transformer is subject to water or moisture is one of the key points of inspection.

To prevent the problem of water ingress and dampness in the transformer, we must first know what are the ways in which the transformer can ingress into water and become damp? Transformers with different structures have different reasons for water ingress and dampness.
There are two ways for moisture to enter the transformer in oil-immersed transformers: respiration and capillary action:

1. Breathing: During the day, part of the air inside the transformer oil pillow is heated and expanded and discharged out of the body. At night, air shrinks and enters the oil pillow. During this "breathing" process, water dissolves in the insulating oil and precipitates into the oil pillow. The bottom causes water intrusion.

2. Capillary action: The distribution transformer has a breathing tube on the upper part of the oil pillow, and a hygroscopic silica gel dryer is connected between the breathing tube and the atmosphere. When the air moisture is too high, the silica gel suction force is full, causing the dryer to fail. Moisture forms an annular water film around the breathing tube, and enters the transformer oil pillow along the breathing tube through capillary action.

Dry-type transformers have a simple structure and fewer accessories, and are better than oil-immersed transformers in terms of moisture resistance. But most of it is an open structure, which is easily affected by moisture condensation in the air. Generally speaking, the ideal working environment for dry-type transformers is an ambient temperature of 20 degrees and a relative humidity of 85%.

In addition, there are also product assembly quality issues such as loose sealing of the transformer and lack of sealing between gaskets and fasteners, which cause rainwater to leak into the transformer. This can generally be avoided by choosing qualified products from regular electrical equipment manufacturers.

Once we understand the ways in which water and moisture can enter the transformer, we can take appropriate countermeasures to prevent equipment damage and safety accidents caused by water and moisture in the transformer. The specific method is as follows:

1. Strengthen inspections of transformers, use an insulation resistance measuring instrument to measure the insulation resistance value, and determine whether there is water or moisture. Frequently check the rubber gaskets and washers of the transformer, and tighten loose parts in a timely manner;

2. There is a height difference of about 3cm between the top of the connecting pipe between the transformer oil pillow and the oil tank and the bottom of the oil pillow. After water enters the oil pillow, it first settles at the bottom of the oil pillow. You can use glycerin, vegetable oil, phenolphthalein, calcium oxide, etc. to prepare a water-sensing indicator paste to check whether there is water and the depth of the water layer in the oil pillow.

3. For transformers that have been affected by moisture, offline drying methods (heating to increase temperature, air blowing to drain moisture, vacuum moisture drainage) or online drying methods (no-load heating) can be used for drying.

Around Qingming Festival, there is also a high incidence of fires. In addition to fires caused by open flames such as burning incense, burning paper and setting off firecrackers, electrical fires caused by water short circuits in electrical equipment are also key hidden dangers that need to be guarded against. Leilang Electric reminds you: Electricity safety is no small matter, and safety inspections need to be carried out regularly, discovered in time, and dealt with as early as possible; choose regular electrical equipment merchants to purchase qualified products to ensure the safety of electricity use in production and life.

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