Frequency Dependence of Conductivity of the Open Channel Region in Water Treed XLPE

Abstract

Loss current through a non-penetrated water treed polyethylene sheet has been studied by changing the applied voltagefrequency from 50 Hz to 1000 Hz of 1000 V. The change of the fundamental and 3rd harmonic components of the loss current for frequency is discussed by taking the capacitance of the water treed sheet sample to be Maxwell-Wagner two-layer capacitor: the capacitance both for the non-treed region and the closed channel region is connected in series to the parallel combination of the capacitance and the conductance for the open channel region. By assuming a non-ohmic dependence of the conductance for the open channel region, the fundamental and 3rd harmonic components of the loss current have been numerically calculatedbased on the equivalent circuit. It has been concluded that the conductance of the opened channel region in the water treedregion is directly proportional to frequency and the conductivity at 1kHz is in the order of 10^-7 S/m.