DETECTING METHOD FOR PARTIAL DISCHARGE IN CROSSLINKED- POLYETHYLENE INSULATED POWER CABLE SYSTEM

摘要

PURPOSE:To detect the partial discharge of an insulating layer without fail before the occurrence of the breakdown of insulation property and thereby to prevent the outbreak of a large hazard, by detecting H2, CO and CO2 produced at the time of the partial discharge from a crosslinked-polyethylene insulated power cable system in which air or gas of SF6 or the like is filled up in a sheath. CONSTITUTION:In a power cable prepared by providing a cable conductor 1 with an internal shielding layer 2, a crosslinked-polyethylene insulating layer 3, an electrostatic shielding body 4 formed by winding a semi-conductive tape with butt gaps 4' provided, a tin-plated copper wire 5 (grounded), a cotton-tape winding layer 6 and a metal sheath 7 in this sequence, air or gas of N2, SF6 or the like is filled up in a gap 8 inside the sheath 7. The gas in this gap 8 is taken out and analyzed by the gas chromatography using an activator column. When one or more of H2, CO and CO2 in the gas is detected, it is determined that the layer 3 is decomposed due to partial discharge and thereby said three gases are produced inside a cable core. The partial discharge can be detected with high sensitivity in this way.