抄録
A comparison of the observed relative magnitude of the 3rd harmonic wave to the fundamental one of ac loss current I3/I1 and phase of the 3rd harmonic wave θ3 with the calculated ones has been done for water tree cross-linked polyethylene. The model used for this calculation takes account of non-linear electrical conduction mechanism in the water tree region and contains two parameters; one of them is a parameter characterizing the effect of electric field on the non-linear electrical conduction and the other is a conductivity at low electric fields depending on frequency of applied voltage. It has been found that this model can explain qualitatively the changes in I3/I1 and θ3 for applied voltage and its frequency.
