Corrugated Board 

Corrugated pressboard is used to build barrier type insulation in electrically stressed volumes of oil. One such application is as filler around HV exit conductors from winding ends, where they pass through the system of “common clack rings” and pressure plates. The thin corrugated strip is interleaved with flat sheet strips to prevent the corrugations to fall into each other from turn to turn. Another application is for main ducts in transformers as an alternative to combinations of flat board cylinder wraps and duct strips. The use of corrugated board is dependent on the requirements of mechanical rigidity against radial forces. A third application is building of barrier systems around unwound outer limbs – again as an alternative to flat-board wraps and duct strips.

There is a variety of different patterns available. Some are indicated as examples in the figures below, and closer information may be supplied on request. Only two standard types are detailed in this catalogue – one for the HV conductor wraps, and one for larger barrier systems.

 
Material and manufacture
Thin corrugated material is rolled between corrugated rollers (sinusoidal corrugation with small pitch).

Thicker material is manufactured by hot pressing, pitch by pitch, between linear pressing beams.

Dimension