PD behaviour of basic test arrangements under different measurement conditions

The PD behaviour of so-called basic test arrangements as for corona discharge or other discharge sources seems to be well known from the physical point of view. On the other hand the measurement results and, in the same manner, their identification and interpretation can be different, because this is depending on the measurement or evaluation conditions. Therefore some typical basic arrangements representing corona discharges as needle-plane, needle-plane with insulating sheet and needle-sphere as well as artificial cavity into insulating material were investigated. In a previous paper the pd behaviour of the corona set-ups in air were already discussed. Additional to that the pd behaviour of typical internal pd source under different measurement condition is described. In this paper the most recognized values are compared at the well defined laboratory set ups as defined. During these investigations the standard evaluation methods according to IEC 60270, PRPD pattern and pulse sequence analysis is done. By comparing these three evaluation types the most significant method for the classification of failure types is discussed. For closer evaluation of image based evaluation methods like PRPD pattern and pulse sequence analysis different methods of classification are discussed. The presented results show surprisingly characteristic shapes of the PD pattern, which allow the better classification of the types of PD sources and their identification respectively.