Evaluation and limitations of corona discharge measurements - an application point of view

The phenomenon of corona discharge has been extensively discussed in numerous publications. However, those studies mostly focused on physical and chemical processes or the comparison of the corona effect for different isolation materials such as air, oil, etc. In this paper the effect of corona partial discharges is investigated from an application point of view. Corona characteristics and discharge patterns are explained and discussed starting from an initial phase which is dominated by Trichel pulses up to the onset of breakdown (pre-breakdown streamers). The limitations of electrical partial discharge measurements for the evaluation of corona discharges are examined.