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The frequency effect of HV and electroluminescence in XLPE

The frequency effect of the ac voltage used for on-site diagnostic tests of underground HV cables is determined with the Electroluminescence (EL) technique. HV up to 28 kV at frequencies from 30 to 600 Hz is applied to semicon tips embedded in cross-linked polyethylene (XLPE). The number of EL pulses detected by a photomultiplier and the area of the space charge region, simultaneously obtained by the CCD camera, are studied. The implications of the frequency range on diagnostic tests performed on the polymeric insulation of underground power cables are discussed.