What is the correct transformer oil sampling procedure?

The correct transformer oil sampling procedure involves several key steps: First, ensure the transformer is offline and cool. Use a clean, dry sampling device to avoid contamination. Remove the sampling valve cap and allow a small amount of oil to flow to purge contaminants. Collect the oil sample in a clean, labeled container, filling it to the recommended level. Finally, seal the container tightly and store it in a cool, dark place until analysis.