Dielectric response measurements in time and frequency domain on high voltage insulation with different response

Diagnostic measurements of dielectric materials can be performed either in time-domain or frequency-domain. If the dielectric material can be described as a linear system the acquired information in the two domains are in theory equivalent. In time-domain charging/discharging currents and recovery voltage are used and in frequency-domain capacitance and loss factor are measured as a function of frequency. These methods are today used as diagnostic methods for example for high voltage cables, transformers and rotating machines. The purpose of this paper is to discuss the relation between time-domain and frequency domain and how well the different existing measurement methods can characterise a dielectric material depending on the material´s response