The life of the transformer is really the life of the insulation system. The most widely used transformer insulation system comprise of liquid insulation (transformer oil) and solid insulation (Kraft paper, pressboard, wood, i.e. cellulose products). The insulating oil provides approximately 80% of the dielectric strength of a transformer. The majority (Approximately 85%) of transformer breakdowns are attributable to the failure of the insulating system. Transformer oil is a good liquid insulation medium and when impregnated in paper, boards and cloths, increases the dielectric strength of these winding insulation materials. The low viscosity of the oil allows it to penetrate the solid insulation and allows convection currents to form, conveying the heat of the core materials to the radiators. The liquid insulation therefore also serves as a coolant. Its oxidation stability allows it to operate at high temperature for long periods without serious breakdown.
Oil, Cooling, Regeneration, Aging
