Conservator level protects the main tank by ensuring proper oil volume for insulation and cooling while accommodating thermal expansion. Low level increases risk of air ingress, moisture absorption, and exposure of active parts, reducing dielectric margin and accelerating aging. High level can indicate overfilling or gas generation and may stress seals or breathers. Level monitoring supports early leak detection and helps maintain stable oil quality by minimizing oxygen and water contamination, especially when paired with breathers and moisture control systems.