What role does a transformer oil inhibitor play in oil stability?

An inhibitor slows oxidation reactions that produce acids, sludge, and polar compounds. This stabilizes interfacial tension and resistivity, maintains dielectric strength, and prevents deposits that reduce cooling efficiency. Inhibitor concentration is monitored because it depletes over time. Proper inhibitor level helps keep oil within specification limits, extends oil service interval, and supports predictable aging behavior. If inhibitor is depleted, oxidation accelerates, especially in units with oxygen exposure or high thermal stress.