Techniques for Localization of Water-treed Regions along Medium-Voltage Power Cables

R. R. Papazyan, U. Gäfvert, R. Eriksson and K. Johansson

o distinguish between the effects of water-tree in XLPE and all other measurement artifacts a measurement procedure was used, based on the voltage nonlinearity of water treed insulation. TDR measurements have been performed before, after and during the application of high AC voltages in order to distinguish the signals related only to insulation ageing. These high stresses affect the cable characteristic impedance and speed of wave propagation in the water-treed region. The possibility to detect local changes in the velocity of wave propagation has been presented as a technique for localization of insulation ageing.

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