What is the procedure for transformer oil change?

The procedure for transformer oil change involves several key steps. First, ensure the transformer is de-energized and isolated. Next, drain the old oil using a vacuum pump, ensuring proper containment for disposal. Inspect the transformer for any signs of damage or contamination. Then, replace the oil filter if applicable. Finally, refill the transformer with new, filtered oil to the appropriate level, and conduct tests to ensure proper insulation and functionality before re-energizing the unit.