Determining if a transformer tank needs maintenance involves a comprehensive assessment of its sealing performance, oil quality, and operational stability through daily inspections, cleaning, and periodic testing. The following are specific inspection items and standards applicable to oil-immersed transformers.
Daily Inspection (Recommended once daily or per shift)
Daily inspection is the first line of defense against abnormalities, focusing on "seeing, listening, and measuring."
Oil Level Check
Inspection Item: Is the oil level in the conservator (oil tank) within the normal range?
Standard: The oil level should correspond to the current ambient temperature, avoiding being too high or too low. A low oil level may cause winding exposure, while a high level can easily lead to leakage.
Abnormal Signal: Significant drop in oil level → Check for leaks or a blocked breather.
Oil Temperature Monitoring
Inspection Item: Upper oil temperature reading (using an oil temperature gauge).
Standard: Generally not exceeding 85℃, and a maximum of 95℃. Temperature rise should not exceed 55℃ (at an ambient temperature of 40℃).
Abnormal Signal: Continuous increase in oil temperature under the same load → Poor heat dissipation or increased internal losses.
Leakage Inspection
Inspection Items: Check for oil leaks or drips in the oil tank, valves, flanges, radiators, etc.
Standard: No visible signs of leakage.
Abnormal Signal: Oil stains on the ground or oil marks on the surface of the oil tank → Aging seals or cracked welds.
Sound Monitoring
Inspection Items: Whether the operating sound is uniform.
Standard: Normal is a continuous "humming" sound.
Abnormal Signal: "Crackling" discharge sounds or irregular vibration sounds → Possible short circuit in the windings or loose iron core.
Appearance and Accessory Inspection
Inspection Items: Check for deformation or corrosion of the housing; whether the silicone breather has changed color (blue → pink indicates moisture absorption); whether there is gas inside the gas relay.
Standard: The enclosure is intact, the breather is dry, and the gas relay is free of air bubbles.
