What performance properties define transformer insulating oil for HV applications?

For high-voltage applications, transformer oil must exhibit high dielectric strength, excellent oxidation stability, low dielectric loss, and strong moisture tolerance. It should maintain consistent viscosity across temperature ranges and have a high flash and fire point for safety. Chemical stability is critical to prevent sludge formation under thermal stress. HV oils must also be compatible with paper insulation and meet strict international standards to ensure reliable long-term operation.