How to check the insulation performance of dry-type transformers

In order to make dry-type transformers safer, the efficiency of dry-type transformers is continuously improved. To enhance the safety performance of dry-type transformers, it is also necessary to pay attention to improving the safety performance of dry-type transformers from the insulation performance of dry-type transformers starting out, the insulation performance of the dry-type transformer is continuously detected, and it is found that the insulation performance is not high, and it is necessary to perform inspection and improvement. So how to check the insulation performance of dry-type transformers?

1. Accurately measure the grounding resistance of dry-type transformers. For power engineering dry-type transformers with a rated voltage of 12 kV, people generally choose 3000V megohmmeters.

2. Before the test, solve the dry-type transformer’s high and low-pressure side pile heads to carry out sufficient charging and discharging, exhaust the internal residues of the dry-type transformer, and then detect.

3. When testing, the insulation layer shake table should be placed at a level position. Hold the insulation layer shake table and place the insulation layer. Watch the meter’s hands gradually rise with shaking and short-circuit the two wires when the speed exceeds infinity. Head: L and E. You will notice that the hands are “O”. Only then use the shaker to test the ground resistance.

4. The insulation layer of dry-type transformer is divided into “high voltage to low voltage, high voltage to ground, low voltage to ground and several conditions, such as the significant difference in the grounding resistance of dry type transformers that should be shielded. Drop detection method (short the copper core wire of the pile head on the high and bottom pressure side to the shake table to shield the top of the pile head). When applying the shield drop method, special attention should be paid to the shielded cable to sense the electrified position. Spacing of electrical locations.

5. If the grounding resistance of the dry-type transformer does not increase significantly after the test, it indicates that the dry-type transformer’s internal and high and bottom pressure waterproof bushing positions will have already regained moisture that dry-type transformers should be used to solve the problem. Another reminder is to remind you to touch the dry-type transformer pile head after charging and discharging.