Investigations of the influence of semi-conductive shields on the frequency- dependent loss factor measurement of XLPE- insulated medium voltage cables

A possibility to diagnose the integral condition of a cable system is the measurement of the dielectric loss factor tan d. Thereby the measured dielectric loss factor tan d is frequency-dependent. Due to a high accuracy and reproducibility, the loss factor measurement over a certain frequency domain considers various factors of influence like the temperature or the humidity of the cable. Moreover, some constructive properties of the cable are also influencing the measurement. With the aid of this loss factor measurement method, the influence of the semi-conductive shields on the loss factor tan d is investigated in this paper. It has been determined that for lower frequencies up to a few Hz the loss factor tan d is dominated by the cable insulation. At higher frequencies, the…