How to Diagnose Faults in Dry-Type Transformers by Sound

How to Diagnose Faults in Dry-Type Transformers by Sound

Dry-type transformers typically operate without any noise, which is normal. However, some processes may produce significant noise, indicating that the sound can help identify potential faults. In fact, the sound of a dry-type transformer can reveal signs of damage. Problems with the sound indicate a fault in the transformer, requiring repair.

**Irrelevant Noises in Dry-Type Transformers:** If the transformer’s sound is louder than normal and contains extraneous noises, but the current intensity is normal, it may be due to loose clamps or nuts securing the core, causing vibration of the ferrite core.

**Charging/Discharging Sounds in Dry-Type Transformers:** If partial discharge occurs in the transformer or its external components, a crackling or popping charging/discharging sound will be present within the overall sound. When this phenomenon occurs, if a dark blue corona discharge or flame is visible near the transformer’s waterproof bushing at night or in rainy weather, it indicates severe contamination of the porcelain components or contact between the equipment clamps. If the transformer is charging or discharging, it is not due to electrostatic discharge from the grounding components, but rather a contact discharge from the tap changer. In this case, the transformer should be further inspected or taken out of service.

Dry-type transformers may make a boiling sound. If the transformer’s sound is mixed with a boiling sound and the ambient temperature changes, and the oil level rises, it indicates a short circuit fault in the transformer windings, or severe overheating of the tap changer due to contact. In this case, the transformer should be taken out of service for inspection.

Dry-type transformers may make a popping sound. If the transformer’s sound is mixed with uneven popping sounds, it indicates that the transformer or its surface insulation has penetrated. In this case, the transformer should be taken out of service for inspection.

The above sound issues are a crucial point that cannot be ignored and need to be carefully understood. Otherwise, the transformer will not function well, and its lifespan may be shortened!