The hottest way to prevent water from entering tra

2022-08-14
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Methods to prevent water from entering the high-voltage bushing of transformer

insulation accidents of power transformer caused by moisture entering the water continue to occur, accounting for about 20% of insulation accidents, posing a threat to the safe operation of electricity

the reason why the transformer is affected by water and moisture during operation is that the silica gel of the conservator respirator cannot be used to meet the purpose of this purchase, and the moisture in the air enters the transformer through the conservator. The probability of this situation is relatively small. Second, the sealing performance of the high-voltage bushing of the transformer is relatively poor, and water flows into the transformer through the top of the high-voltage bushing

the connection cap on the top of the high-voltage bushing of the transformer is poorly sealed, and moisture enters the winding insulation along the lead, causing a breakdown accident. Casing top connection is an ideal test equipment for scientific research institutions, colleges and universities, industrial and mining enterprises, technical supervision, commodity inspection and arbitration departments. The poor sealing of cap is due to unreasonable structure and incorrect installation of rubber gasket. It is known that the terminal block of the connecting cap on the top of the bushing is connected with the threaded lead nose. This connecting cap has the dual functions of sealing and conducting electricity, which brings many disadvantages. First, the manufacturing tolerance of fine thread thread is too large, and poor contact causes heating; Secondly, the copper pin for fixing the lead wire is too long, and the terminal block used for connecting the cap must also be consistent with the connection of the external bus, so that the gasket cannot be pressed tightly, and water will leak inward if it is slightly loosened. In an insulation accident, the burned out part of the winding is usually near the lead, which indicates that water enters along the bushing lead

Figure 1 high voltage bushing of transformer after transformation

during the inspection of bushing of main transformer, we found that the connection cap on the top of domestic bushing was poorly sealed. When the lead was blown by strong wind, the sealing rubber ring would squeeze to one side, and there would be a vacancy on the other side, which could not prevent rainwater from penetrating. In order to eliminate this potential accident, it is decided to add a copper cap on the top of the casing (see Figure 1). Its principle is: the joint on the winding lead is fixed on the copper cap through threads, and the copper cap is then connected with the external lead, so that the joint on the winding lead will not be in contact with the outside, and the future will be a painful debt repayment period, thus preventing the entry of rain. We transformed the high-voltage bushings of several transformers. After adding a copper cap on the top of the bushing, we found that no rainwater leaked into the transformer through the bushing

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