The quality of variable pressure oil can only be identified through pressure test. But unqualified oil can be roughly identified from its appearance. Precautions for taking oil samples from transformers: Oil samples should be taken on dry and sunny days; The container containing oil should be clean, dry, and opaque; Take an oil sample from the valve at the bottom of the transformer, and the oil sample should be promptly sent to the testing unit without prolonged delay.
1. Color: New oil is usually light yellow, but after long-term operation, it turns dark yellow or light red. If the oil quality deteriorates, the color will darken and have different colors; If the oil turns black, it indicates severe carbonization and cannot be used.
2. Transparency: The oil should be transparent when observed in a glass test tube at temperatures above -5 degrees Celsius. Poor transparency indicates the presence of free carbon and other impurities.
3. Fluorescence: A new oil placed in a test tube that, when viewed against light, exhibits milky green or blue purple reflections on both sides, known as fluorescence. If the used oil has no fluorescence at all, it indicates impurities and decomposition products in the oil.
4. Odor: Good transformer oil only has a slight smell of kerosene or odorless. If the oil has a burnt smell, it indicates that the oil is not dry; If the oil has a sour taste, it indicates that the oil has severely aged. When measuring the odor, the oil sample should be stirred well and slightly heated. If you feel suspicious, you can also add a few drops of oil and rub it on a clean hand to identify the odor.
Precautions for taking oil samples from transformers: Oil samples should be taken on dry and sunny days; The container containing oil should be clean, dry, and opaque; Take an oil sample from the valve at the bottom of the transformer, and the oil sample should be promptly sent to the testing unit without prolonged delay. (Test Article)