Investigating Partial Discharge Behaviour and Extracting Diagnostic Markers for Partial Discharge Aging of Type i Insulating Materials

This paper deals with investigation of Partial Discharge (PD) and surface erosion endurance on Type I (organic) insulation. Considering two types of reference materials of the Kapton family, one having enhance resistance to PD (CR, corona resistant), a short-term PD test procedure using needle-plane electrodes was devised in order to get fast characterization of the capability of an insulating material to endure PD. Partial Discharge data and surface erosion were acquired and measured hourly, in order to obtain both a life line plot and a time behaviour of the erosion depth. Life lines were also obtained through accelerated electrothermal life tests, using cylindrical-shape electrodes. The results show significantly different PD endurance and erosion rate between the two tested materials, thus indicating that the investigated short-term procedures may be useful for the selection of insulating materials and for the estimation of the design field.