Measured PD pulses in vegetable-oil-impregnated insulation system

Results of PD tests in vegetable oil impregnated insulating system are discussed in this paper. The main objective of the study is to investigate the PD behaviour in the particular insulating systems at elevated temperature. Two different sample arrangements of electrical pressboard and insulating paper were used to simulate insulation defects. The sample was placed in a glass cell and was fully immersed in vegetable oil. The initiated PDs were detected and analysed using a wide band PD detector. The PD waveforms were picked up by means of a HFCT sensor and displayed using a digital oscilloscope. Investigation results show that there are some differences in intrinsic characteristics of PD pulses measured from the two different sample configurations.