Constructionally, pressure cable is similar to that of an ordinary solid type’s cable except that it has a triangular shape. Triangular formation helps to reduce the weight of the cable also the thickness of the lead sheath is 75 per cent of that of a solid type of cable Bedding and serving are not provided to pressure cable which helps in decreasing the thermal resistance.
But cable is provided with a thin layer of armouring so that the formation of any abnormal ties over its surface is avoided. Cable is installed in a gas-tight pipe of the somewhat large area and the pipe is filled with nitrogen gas at a pressure of 12 to 15 atmospheres which continuously compresses the cable radically from outside so that radial breathing o cable occurs and any voids etc. are closed.
- These cables are used for voltage above 132kV.
- These are at HT terminal of the power transformer.