Essential Dry-Type Transformer Maintenance Steps

Routine Maintenance and Care of Dry-Type Power Transformers

Due to their flame-resistant and self-extinguishing properties, high mechanical strength, and ability to withstand large short-circuit currents, dry-type transformers are easy to operate and maintain. However, under poor ventilation conditions, their heat dissipation performance is inferior to that of oil-immersed transformers. Therefore, the key focus in the operation and maintenance of dry-type transformers is controlling the temperature rise during operation.

How should dry-type transformers be maintained and cared for?

• Regular cleaning of the equipment. Dust accumulation must be removed promptly to ensure proper airflow and prevent insulation breakdown. Transformers should be thoroughly cleaned and dusted every six months, and the surrounding environment should remain dry and well-ventilated.

• Enhance operation and maintenance of ventilation systems. Ensure cooling fans operate normally. For high-capacity transformers, turbo fans should be used to improve cooling efficiency.

• Monitor temperature and humidity changes. Maintain a balanced temperature and humidity level, paying close attention to sudden changes in relative humidity readings. Ensure the temperature controller functions properly to prevent failures. Equip the transformer with built-in thermal resistors in a redundant configuration to enhance reliability and prevent transformer faults.

• Inspect for moisture and condensation in cold, humid conditions. If operation is suddenly interrupted in cold and humid environments, check for abnormal moisture or frost formation. Any ice or frost on the surface must be removed to prevent insulation breakdown and ensure normal operation of the insulation windings. As long as the insulation resistance is not less than 2 MΩ per 1000 V, the transformer can operate normally. The heat generated during operation will restore the insulation resistance to normal levels. Under normal operating conditions, the transformer’s body temperature is higher than the ambient temperature, so insulation resistance typically does not decrease.

• Inspect fasteners and connections for looseness. In addition to short circuits, prolonged operation may cause vibration-induced loosening of fasteners and connecting parts, potentially leading to overheating. Regular inspections, temperature monitoring (e.g., using temperature-sensitive wax), preventive testing, and tightening of loose components are essential to ensure safe and reliable operation.