Transformer Bushings

The insulators used where an HV conductor passes through an earthed metal wall (or similar) are known as 'bushings'. Foil grading is used to control the voltage distribution in the
bushing. The porcelain covering added to the external half of the bushing consists of a stack of discs (referred to as 'shedding'). It is used to increase the creepage distance and break up the flashover path.