Insulation components and insulation sheets made of pressboard are primarily used in oil-filled power transformers and distribution transformers because of their high purity, mechanical strength and optimum oil impregnability.
Due to a different drying process for calendered boards the shrinkage factors are higher compared to pre-compressed boards. Calendered boards are preferred when a flexible insulation board is required, such as for small angles, barriers or protections. Calendered boards are also used for different insulation applications in liquid-filled distribution transformers like core formers, cooling ducts, barriers and cylinders.
Hitachi ABB Power Grids produces calendered boards in different densities depending on the application.