Maintenance of oil-immersed transformers is crucial for ensuring their long-term stable operation, extending their service life, and preventing failures. Below is a detailed maintenance guide covering daily inspections, regular maintenance, common issue resolution, and safety precautions:

　　I. Daily Inspections and Maintenance

　　1. Visual Inspection

　　Inspection Frequency: Daily or weekly.

　　Inspection Contents:

　　Check if the transformer casing is intact, with no signs of rust or oil leakage.

　　Ensure that accessories such as radiators, oil conservators, and breathers are clean and free from blockages.

　　Verify that the grounding wire is secure, with no breaks or loosening.

　　2. Oil Level and Temperature Monitoring

　　Inspection Frequency: Daily.

　　Inspection Contents:

　　Observe the oil level through the oil level gauge to ensure it is within the normal range (typically between 1/4 and 3/4 of the gauge).

　　Monitor the oil temperature using an infrared thermometer or the built-in thermometer of the transformer to ensure it stays within the normal range (usually not exceeding 85°C).

　　3. Sound and Vibration Check

　　Inspection Frequency: Daily.

　　Inspection Contents:

　　Listen to the sound of the transformer during operation, which should be a uniform humming noise.

　　Check for abnormal vibrations in the transformer and its accessories, ensuring that the vibration amplitude is within acceptable limits.

　　II. Regular Maintenance and Testing

　　1. Oil Sample Analysis

　　Maintenance Frequency: Every six months to one year.

　　Maintenance Contents:

　　Collect oil samples from the transformer for laboratory analysis to check indicators such as acid value, moisture content, and breakdown voltage.

　　Decide whether an oil change or filtration is necessary based on the analysis results.

　　2. Insulation Testing

　　Maintenance Frequency: Annually.

　　Maintenance Contents:

　　Measure the insulation resistance of the transformer using an insulation resistance tester to ensure good insulation performance.

　　Perform a DC resistance test on the windings to check for short circuits or open circuits.

　　3. Cleaning and Tightening

　　Maintenance Frequency: Every six months.

　　Maintenance Contents:

　　Clean dust and dirt from the transformer casing and accessories.

　　Check and tighten all terminal connections, bolts, and nuts to ensure secure connections.

　　III. Common Issues and Solutions

　　1. Oil Leakage

　　Issue Manifestation: Oil stains appear on the transformer casing or accessories.

　　Solution:

　　Identify the leakage point and replace the sealing gasket or tighten the bolts.

　　For transformers with severe oil leakage, shut down for maintenance and replace damaged components.

　　2. Abnormal Oil Level

　　Issue Manifestation: The oil level is too high or too low.

　　Solution:

　　If the oil level is too high, check if the breather is clogged and, if necessary, release oil to the normal level.

　　If the oil level is too low, promptly replenish oil to the normal level and check for oil leakage.

　　3. Excessive Oil Temperature

　　Issue Manifestation: The transformer oil temperature exceeds the normal range.

　　Solution:

　　Check if the load is too high and, if necessary, reduce the load.

　　Check if the radiator is clogged and clean its surface.

　　Check for internal faults in the transformer, such as winding short circuits.

　　IV. Safety Precautions

　　Power-Off Operation: Before performing any maintenance or inspection, ensure that the transformer is de-energized and hang a "Do Not Close" warning sign.

　　Personal Protective Equipment: Maintenance personnel should wear appropriate personal protective equipment, such as insulating gloves and shoes, to ensure personal safety.

　　Fire Prevention Measures: Equip the area around the transformer with sufficient fire-fighting equipment, such as fire extinguishers and sandboxes, to prevent fire accidents.

　　Professional Maintenance: For complex maintenance tasks or fault handling, seek the assistance of a professional maintenance team to avoid accidents caused by blind operation.

　　V. Professional Maintenance Recommendations

　　Regularly Hire Professional Teams: It is recommended to hire a professional maintenance team at least once a year to conduct a comprehensive inspection and maintenance of the transformer.

　　Establish a Maintenance Archive: Record the transformer's maintenance history, oil sample analysis results, insulation test data, etc., to provide references for future maintenance.

　　Train Maintenance Personnel: Regularly train maintenance personnel to improve their professional skills and safety awareness.

　　By following the above maintenance guide, you can ensure the long-term stable operation of oil-immersed transformers, extend their service life, and reduce the probability of failures.