How to operate, maintain and maintain dry-type transformers?

We know that the dry-type transformer can’t take too long from manufacture to put into use, so as not to damp and rain the insulation, otherwise it needs to be re-dried. By opening the transformer casing, the maintenance of the dry-type transformer body and the switching of the winding taps can be conveniently carried out. It is also very convenient to observe and monitor the operating status of the transformer. During installation, set a rubber pad between the transformer and the installation foundation to reduce the vibration and noise of the transformer.

How to operate and maintain dry-type transformers?

1. Regular cleaning: If the dust accumulates too much, it should be cleaned immediately to ensure air circulation. In dusty areas, dry-type transformers should be cleaned at least every six months. For dust in ventilation ducts. Vacuum cleaner or compressed air for cleaning. If it is not removed in time, it will affect the heat dissipation of the transformer, reduce the insulation performance of the transformer, and even lead to insulation failure. For example, the 35kV substation transformer of our company’s 220kV Weizhuang substation is undergoing a power outage test. The insulation resistance of the dry-type transformer core was measured with a 2500V optical ohmmeter. The insulation resistance of the core is reduced to 3 mΩ, well below last year’s test data of 100Ω. The main reason is that the dust in the transformer ventilation duct is not cleaned up. After cleaning, the insulation resistance of the core rose to 100Ω.

2. Actively carry out dehumidification and dehumidification to ensure dryness: in some humid places (such as rainy and dark places), such as using a dry-type transformer that has been stopped, check whether the humidity is abnormal. If so, start hot air to dry the surface to prevent insulation damage. For the oxygen-cast dry-type transformer, the surface moisture does not affect the insulation inside the winding, so it can be put into operation after treatment. Once the transformer is put into operation, the heat generated by its losses will restore the insulation resistance to normal.

3. Carefully check whether the fasteners and connecting parts are loose to ensure the mechanical strength of the dry-type transformer: For long-term operation of the transformer, due to external knowledge and other reasons, it is unavoidable that the fasteners and connecting parts are loose due to force and vibration . If the above phenomenon occurs, a hot spot may occur. To this end, the temperature indicating wax plate should be set at the high and low pressure ends and all places where overheating may occur, regular observation, combined with cleaning and preventive tests, tighten the ends and connectors of the wax plate.

4. Actively carry out the iron core derusting work to prevent the iron core from rusting: the dry-type transformer iron core is exposed to the air and is easy to rust. If the iron core is rusted in a large area, it will increase the loss and efficiency of the transformer, and even directly affect the service life of the transformer. Therefore, it is necessary to remove rust regularly to prevent the iron core from rusting.

Post time: Apr-23-2022
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