Other parts of power transformers

Insulating Materials

Insulating materials are used to isolate the windings from the core, the primary and the secondary windings, and each turn of the windings. These materials protect the transformer from damage. Transformer insulators should have high dielectric strength, good mechanical properties, and can withstand high temperatures.

Paper and pressboard can be used as an insulator (i.e., dry-type transformers); however, they have limited service lives and require frequent replacement as these materials can degrade. Hence, transformer oils are more common compared to solid insulating materials. They provide enhanced insulation between conducting parts, act as a coolant for the coil and windings assembly, and have fault detection features. Hydrocarbon mineral oils consisting of aromatics, paraffin, naphthene, and olefins are used as transformer oils. Oil contamination must be prevented to preserve the oil’s dielectric properties and insulating features.