What does the color of transformer oil indicate?

The color of transformer oil is an important indicator of its condition and quality; typically, fresh transformer oil is pale yellow to light amber in color, indicating purity and low levels of contaminants. As the oil ages or becomes contaminated, its color may darken, ranging from amber to brown or even darker shades, suggesting the presence of oxidation products, moisture, or particulates. A noticeable change in transformer oil color can signify reduced insulation properties, potential degradation of electrical performance, and the necessity for testing or replacement. Regular monitoring of transformer oil color, along with other tests, is essential for maintaining the efficiency and reliability of transformers.