What specific properties of transformer oil are most affected by oxidation, and how does this impact the transformer's lifespan and performance?

Oxidation is a chemical reaction where transformer oil reacts with oxygen, leading to degradation of the oil's properties. Several specific properties of transformer oil are most significantly affected by oxidation. Acidity increases as oxidation produces organic acids. Increased acidity corrodes the transformer's internal components, such as windings and core, and accelerates the degradation of the paper insulation. Interfacial tension (IFT) decreases. IFT is a measure of the surface tension between the oil and water. As oil oxidizes, it forms polar compounds that reduce IFT, indicating the presence of contaminants and degradation products. Color darkens. Oxidation causes the oil to become darker, which is a visual indicator of degradation. Dielectric strength decreases. Oxidation products reduce the oil's ability to withstand electrical stress, increasing the risk of electrical breakdown and flashovers. Viscosity increases. Oxidized oil becomes thicker, which reduces its ability to circulate and cool the transformer effectively. Sludge formation occurs. Oxidation leads to the formation of sludge, which is a thick, insoluble substance that can deposit on the transformer's windings and core, impeding heat transfer and reducing cooling efficiency. The dissolved gas analysis (DGA) results are also impacted. Oxidation can affect the generation rates of certain dissolved gases, complicating fault diagnosis. These changes due to oxidation significantly impact the transformer's lifespan and performance. Reduced cooling efficiency due to increased viscosity and sludge formation can lead to overheating, accelerating the aging of the paper insulation. Decreased dielectric strength increases the risk of electrical failure. Corrosion caused by increased acidity damages the transformer's internal components, reducing its reliability. The overall result is a reduction in the transformer's lifespan, increased maintenance requirements, and a higher risk of catastrophic failure. Monitoring oil properties and implementing mitigation measures, such as oil reclamation or replacement, are essential to minimize the impact of oxidation and extend the transformer's service life.