Development of a sequential discharge data capture system

HV defect analysis and categorisation to date, has in general, been based on the use of statistically driven techniques. Pulse sequence analysis (PSA) proposes that PD activity is more deterministic, with the occurrence of pulses dependant upon the defect type and supply cycle but also the effects of charge deposition at the discharge site from previous PD and its dissipation rate. The main characteristic of interest is the supply voltage difference between points at which discharges occur, as opposed to the phase of occurrence. PSA therefore involves the capture and analysis of sequential PD activity. This paper details the development of a system, capable of capturing sequential PD activity for PSA. The system utilises advances in PC instrumentation techniques which have become available since PSA was first proposed. An examination of the limitations of the new system and the measures taken to reduce these are presented along with some PSA results obtained using a basic defect geometry.