Outdoor Distribution Transformer Enter Water

For outdoor distribution transformer working outdoors, especially in rainy days, transformers working outdoors have no moisture-proof countermeasures, and precipitation is very easy to enter the interior of the transformer, causing common transformer failures. How do you know whether there is water in the transformer? The following are the inspection methods and solutions to distinguish the water in the outdoor distribution transformer.

Inspection method: Transformer oil is sampled for full moisture test, which should be less than 50mg/L. Do dielectric loss and breakdown field strength experiments to check.

Solution: many exceeding the index value. Be sure to oil-water separator, which rarely works but needs to be continuously tested.

Specific steps: After filling the transformer with oil, keep it still for more than two days, then release the appropriate oil (with a capacity of 100 mm at the bottom of the dry-type transformer body) from the bottom, and perform the moisture test and chromatography on the released oil. Yes, it can operate with full oil, but if it is not passed, put some more and do experiments until it reaches the standard. Since water is denser than oil, the water will sink below, and the wet oil can be replaced.

After it is clear that the outdoor distribution transformer enters the water, it should:

1. Stop the operation as soon as possible;

2. Completely drain the transformer oil;

3. Try to air dry the dry-type transformer, especially the high-voltage winding;

4. After it is completely dry, it can be filled with new transformer oil;

5. Use the high-voltage grounding shaker to test the insulation layer of the AC withstand voltage, and then the capital can be put into operation after reaching the standard.

The above is the solution to distinguish the water inflow of the transformer. The water inflow of the transformer will cause a short-circuit fault of the transformer, resulting in the transformer being burned and a fire accident. Therefore, it must be dealt with immediately.