Development of 275kV metal sheath-less XLPE cable

The metal sheath XLPE cables are usually adopted for 275kV underground power cables. Recently it has been desired to omit the metal sheath from the viewpoint of cost reduction. Therefore, the authors researched and developed the 275kV metal sheath-less XLPE cable. The aluminum-laminated tape is selected for the water shielding layer, considering the influence on environment. First they tested how much the water shielding layer would be damaged by the motor-rollers and free-rollers used in the long cable laying. They found that the aluminum-laminated tape had more advantages than the lead-laminated tape in mechanical characteristic. Next they carried out the long distance cable laying test and they examined the thermomechanical behavior of the metal sheath-less cables in snaking form. There was no damage at aluminum laminated tape and insulation materials for each test and there is no problem in the thermomechanical behavior.