1. Introduction

2. Preventive Maintenance

• Regular Visual Inspection
  • Check the exterior of the transformer for any signs of damage, such as cracks or deformations in the casing. Ensure there is no foreign matter attached to the surface, which could affect heat dissipation.
  • Examine the terminal connections to make sure they are tight. Loose connections can cause overheating and affect the normal operation of the transformer.
  • Inspect the insulation protection to ensure it is in good condition, without any signs of damage or aging.
• Environmental Management
  • Ensure that the installation environment of the transformer has good ventilation to prevent overheating. In high - humidity or coastal areas, special attention should be paid to preventing moisture and salt - fog corrosion, as they can cause insulation breakdown or metal part rust.
  • Keep the area around the transformer clean, free from dust and corrosive gases.
• Insulation Oil Maintenance (for oil - immersed transformers)
  • Regularly test the quality of the insulation oil, including indicators such as insulation strength, water content, acid value, and breakdown voltage. If the oil quality deteriorates or the water content increases, timely replace or filter the oil.
  • Use an infrared thermal imager to regularly detect the oil temperature and winding temperature to prevent local overheating and reduce thermal aging. Monitor the dissolved gas in the oil (DGA) to analyze the gas components in the oil and detect potential internal faults of the transformer, such as partial discharge, overheating, or short - circuit.
• Winding and Core Maintenance
  • For windings, focus on checking the inter - turn insulation, the tightness of joints, and the mechanical fixation of coils. Due to the electromagnetic force and temperature changes during operation, the coils may vibrate, which could lead to looseness or even disconnection over time. Therefore, mechanical fixation and vibration detection are very necessary.
  • For the core, check for any abnormal noise and local overheating. If the core is not tightly clamped or is loose, it may cause increased vibration noise and even local short - circuits. In necessary cases, demagnetize the core to prevent residual magnetism from affecting the next operation.
• Cooling System Maintenance
  • For natural - cooling transformers, regularly clean the dust and debris on the heat - dissipation fins to avoid blocking air circulation.
  • For forced - oil - circulation cooling systems, pay attention to the operation status of the oil pump and the tightness of the pipeline to avoid cooling oil leakage. Ensure that the temperature control and alarm devices of the cooling device are sensitive and accurate to prevent winding overheating caused by insufficient cooling. Regularly lubricate the cooling fans to keep the heat - dissipation capacity in the best state.
• Grounding System and Protection Device Inspection
  • Verify that the grounding wire is firm and the grounding resistance meets the design requirements. A loose or poorly - connected grounding wire can cause the potential to rise, increasing the safety risk of the equipment and operators.
  • Regularly detect the sensitivity and triggering function of protection devices such as over - current protection, differential protection, and temperature - protection devices. Use the method of regularly simulating fault signals to verify whether the relays and control circuits respond normally, ensuring that the protection device can cut off the power in a timely manner when the transformer malfunctions.

3. Predictive Maintenance

• Oil Analysis (DGA)
  • Collect oil samples periodically and use gas chromatography to measure the levels of gases such as hydrogen, methane, acetylene, and ethylene dissolved in the insulating oil. An abnormal increase in the concentration of these gases may indicate potential faults such as overheating, arcing, or insulation breakdown inside the transformer.
• Partial Discharge (PD) Monitoring
  • Use sensors and monitoring equipment to detect electrical discharges occurring within the transformer's insulation system. Regular analysis of partial - discharge data helps predict insulation deterioration, allowing for timely maintenance to prevent insulation failure.
• Thermography (Infrared Scanning)
  • Use infrared cameras to scan the transformer's external surfaces, bushings, and connections to identify hotspots and abnormal heating. This can help detect potential faults such as loose connections, high - resistance joints, or overloading.

4. Corrective Maintenance

• When the transformer shows abnormal symptoms such as output voltage anomalies, increased noise, overheating, or frequent tripping, timely troubleshooting is required.
• For voltage - abnormal problems, if it is caused by insufficient input voltage, check the power supply line and equipment; if it is a winding problem, repair or replace the winding.
• For noise problems caused by mechanical vibration, check and reinforce the loose parts and ensure that the equipment is not overloaded.
• If overheating occurs, immediately limit the load operation and check the ventilation situation. If necessary, add heat - dissipation equipment.
• For frequent - tripping problems, detect the settings of the protection device to ensure that they meet the requirements of the equipment operation.

5. Maintenance Records and Documentation

• Keep detailed records of each maintenance, inspection result, and abnormal situation. This includes the date of maintenance, the items inspected, the test results, and any problems found and their solutions.
• Analyze historical data regularly to track the operating trend of the transformer, predict potential hidden dangers, and adjust the maintenance plan in a timely manner.