When is it necessary to perform traction transformer oil replacement?

Oil replacement is necessary when the oil’s insulating and cooling properties degrade beyond acceptable limits, which cannot be restored through purification or regeneration. Indicators include high acidity, excessive moisture content, significant sludge formation, or irreversible chemical changes detected through oil analysis. Replacement may also be required after severe faults or contamination events. Timely oil replacement prevents insulation failure, overheating, and potential transformer breakdowns, ensuring continued safe and efficient operation.