Results from the UHF sensor show that PD events in point
cathode consist of a train of single pulses with ascending
magnitude which cannot be resolved by the lower bandwidth
of standard capacitive coupling circuits. Meanwhile, during
positive discharges, only one single event is seen with much
higher magnitude than negative discharges. These results are
in line with previously published observations [3].
It is difficult to quantify PD magnitude from UHF measurement
due to the variability in the energy received by the
sensor. This is thought to be because of the chaotic behaviour
of charge dynamics during streamers, which results in the
variability of the UHF pulse shapes