Negative partial discharge in compressed air: sequential characteristics evolving over time

When erratic and low-intensity discharges were produced along a gap formed by the interface between compressed air and epoxy, a discharge regime could be described based on the recording and analysis of digitized real-time sequences. It was established that the discharge regime thus observed could be greatly modified, once the insulation system was submitted to partial discharge over time. Indeed our methodology of work allowed us to detect and describe the new discharge regime. The occurrence of the change was observed to be more drastic than progressive. The new regime showed a marked presence of discharge events consisting of isolated single pulses and short pulse sequences. These short sequences would be non-equilibrium discharge events.