Investigation of polarization processes on thin PVC film insulations by the comparison of frequency domain spectroscopy and Extended Voltage Response measurements

In this paper the slow polarization processes were investigated on 1 mm thick PVC samples. The specimens contained four different mass fraction of di-octyl phthalate (DOP) plasticizer. This polymer type is a widely used cable insulating material in the electrical industry e.g. low voltage distribution cables, cables in nuclear power plants etc. By means of a Megger IDAX 300 device, dissipation factor and complex capacitance were measured. Extended Voltage Response measurements, that not only allows the separate investigation of conductive and polarization processes but various time constant polarization processes can be also examined, were also carried out and the results were compared. By means of an iteration method, from the results of the Extended Voltage Response measurements the changing of the slower polarization processes' properties were investigated. The parallel measurements have opened the door to examine the slow polarization processes more precisely.