Aging behaviour of polypropylene under various voltage stresses

Practical HVDC systems have superimposed AC or transients and the synergistic effect of these factors on polymer aging would be of interest.Although it is clear that partial discharges under AC stress will gradually degrade the insulation behavior of a polymeric material, there are not many publications detailing the effect of superimposed AC voltages on polymer performance in a HVDC power system.Assuming polypropylene (PP) is suitable for use as electrical insulation, this paper considers the behavior of PP under various voltage ratios and temperatures.Factors which cause the degradation of PP will be summarized and explained.To simulate the working condition, electro-thermal aging equipment will be used.Fourier transform infrared spectroscopy -attenuated total reflection (FTIR-ATR) measurement and dielectric spectroscopy measurement will be carried out before and after aging.