Dry-type transformers are completely noiseless during normal operation. Therefore, when there is a lot of abnormal sounds, it is an indication that the operation is not normal. At this time, the sound can be used to determine whether the transformer is faulty.

Generally speaking, when the dry-type transformer has the following abnormal sounds, it means that the transformer has a fault.

The specific sound problems are as follows:

If the sound of the transformer is mixed with the sound of boiling water and the temperature changes sharply, and the oil level rises. It should be assumed that the transformer winding has a short circuit fault, or that the tap switch is seriously overheated due to poor contact. In such cases, the transformer should be immediately stopped for inspection.

The dry-type transformer has noise. If the sound of the transformer is louder than usual and there are no obvious current or voltage issues. It may be caused by the loosening of internal clamps or screws that tighten the core, which could result in increased vibration of the silicon steel sheet.

A dry-type transformer may exhibit a crackling sound. If the transformer sound is accompanied by uneven crackling. This indicates that the insulation inside or on the surface of the transformer may have been compromised. In such instances, it is advisable to immediately halt the transformer for inspection.

A dry-type transformer may also emit a discharge sound. In the event of partial discharge occurring inside or on the surface of the transformer, the sound will be accompanied by a "crackling" discharge sound.
If it is at night or in rainy weather, you may observe blue corona or sparks near the transformer bushing. This indicate that the porcelain parts are severely dirty or that the equipment wire clamps are not making a good connection.
If the transformer is discharging internally. It is likely due to static discharge from ungrounded parts, or the tap changer is not making a good connection and discharging. In such cases, the transformer should be further tested or deactivated.

All the above abnormal sounds problems are important to address. It is important that all staff are aware of these issues and that they are maintained in a timely manner. Failure to do so may result in poor use of the dry-type transformers and may also shorten their service life.