Why does the breakdown voltage of transformer oil decrease over time?

The breakdown voltage of transformer oil decreases over time due to several factors that affect its insulating properties. Firstly, the presence of moisture in the oil can significantly reduce its breakdown voltage, as water acts as a conductive medium that facilitates electrical discharge. Additionally, the accumulation of particulates and contaminants, such as dirt and wear debris, can create conductive paths within the oil, further lowering its breakdown voltage. Oxidation of the oil occurs when it is exposed to heat and air, leading to the formation of acidic compounds and sludge, which impairs its insulating capabilities. Moreover, the thermal degradation of oil components can alter its molecular structure, diminishing its effectiveness as an insulator. Regular testing with Globecore oil testers is essential to monitor these changes and ensure the reliability and safety of transformers. Therefore, understanding why does transformer oil breakdown voltage reduce is crucial for maintaining optimal transformer performance and longevity.