How to Clean Your Dry-Type Transformer

dry-type transformer. Periodically removing this dirt is necessary to keep your transformers running properly.

 

 

• Increase the risk of insulation failure.

A routine cleaning and inspection schedule is one of the simplest ways to extend the life of your transformer.

 

Why Dry-Type Transformer Cleaning Matters

Dry-type transformers rely on air cooling and solid insulation (e.g., epoxy resin) to operate safely. Unlike oil-immersed transformers, their internal components are more exposed to environmental contaminants. Here's why regular cleaning is non-negotiable:

 

• : Dust buildup on windings and cooling fins reduces heat dissipation, leading to increased core losses and potential thermal damage.
• : Debris (especially conductive particles) can compromise insulation resistance, raising the risk of short circuits or breakdowns.
• : Clean transformers experience less wear and tear, reducing the need for premature repairs or replacements.
• : Many industry standards (e.g., IEC 60076, GB/T 1094) require regular maintenance to meet safety and performance criteria.

 

Dry-Type Transformer Inspection and Cleaning Guidelines

 

Regularly inspect the transformer for signs of dust or debris accumulation. Conducting inspections at least once annually helps prevent overheating, arcing, or overvoltage tracking.
Ensure the transformer is de-energised before inspecting or cleaning the equipment.

• Live busbars, tap changers, and connection points: These exposed, non-insulated areas are prone to debris accumulation.
• Top and bottom of winding assemblies: Deposited dust often hides in the corners of the coils.
• Enclosure ventilation openings: Blockage here directly impacts cooling performance.

 

If insulation surfaces show signs of tracking or carbonisation, this indicates potential damage to the transformer – manifested as black scorch marks on the insulation layer.

 

 

If you see burn marks, immediately remove the unit from service. It should be inspected and tested before it is used again. It may need to be repaired or replaced.

 

 

For a light cleaning, you can use a vacuum or compressed air to clear your transformer's windings of debris. Or, use both:

 

1. Vacuum Cleaning

First use a vacuum to remove loose dust from coil surfaces and crevices.

 

2. Low-Pressure Compressed Air

 

After vacuuming, a second pass with compressed air helps loosen any particles the vacuum didn't reach.

• below 25 PSI to avoid damaging insulation or shifting conductors.

 

These two steps together provide a thorough dry cleaning without risking moisture intrusion.

 

 

 

• Use a dry, lint-free, non-abrasive cloth to wipe away any dust or debris.‍
• . Many solvents and detergents can degrade insulation materials or leave conductive residue.

 

 

Some larger dry-type substations have removable vent filters to help maintain clean airflow. These filters should also be inspected and cleaned regularly.

 

• Remove the steel filter cover by loosening the retaining screws.
• Pull the filter out using the provided tabs.
• .
• Allow it to dry completely before reinstalling.

 

 

If the transformer is installed in a relatively dust-free environment, an annual cleaning is enough. In a dusty environment, more frequent cleaning and inspection may be necessary.

 

 

Facing issues like excessive noise or decreased insulation resistance of dry-type transformers? Click to consult-GNEE technical team is available 24/7

 

Maintenance While the Dry Type Transformer Is De-energized
. Use either a vacuum or compressed air to avoid directly touching the components. Ideally, use both methods.

 

Dry-Type Transformer Maintenance Checklist
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between 20 and 30 years

Dry-type Transformers: Typically last between 20 and 30 years. Power Transformers (oil-filled): These can last anywhere from 30 to 50 years, depending on the operating conditions and the frequency of maintenance.

 

The most significant distinction between the two transformers is their cooling medium. Dry-type transformers employ air as a cooling medium, while oil-filled ones, as the name suggests, use oil.