Improvement of the XLPE-insulated distribution cables and development of the hot line cable monitoring systems

Crosslinked polyethylene insulated power cables (XLPE cables) were first used for 6 kV distribution lines in Japan in 1959. Since then, XLPE cables have been widely used in transmission and distribution systems because of their many advantages in comparison with oil-filled cables, such as good electrical properties and easy-maintenance and handling. XLPE cable, however, involves a problem of water tree deterioration. Water treeing began to be an actual problem in about 1967, mainly with 6 kV XLPE cables for power distribution, and a solution has since been urged. The authors introduce actual instances of water tree deterioration and describe some improvements to the cable which may solve the problem. Development of an instrument that enables live line diagnosis of the deterioration is also described in detail.<
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