Section Locating of Water-tree Degraded Cable by Measuring Residual Charges Induced by Induced Voltage Pulses

To establish a novel section locating technique for a water-tree degraded 22 kV cross-linked polyethylene (XLPE) cable that is included in another undegraded cables, we measured a reflected injection pulse at the impedance mismatch which is dependent on water trees. The injection pulse was propagated into cables to be measured, and the measured arrival times of reflected pulses containing residual charges due to water trees were varied depending on the locations of water-tree degraded cables. The section locating was achieved by using arrival time of the reflected pulse.