Corona Discharge Modes and Their Detections Under DC and AC Voltages

This article presents the corona discharge light patterns for three different electrode systems under +DC, -DC, and AC voltages and also compares the availability of corona discharge detection sensors. The electrode gap spacing was selected as 6 cm for these electrode systems to observe several corona discharge modes under atmospheric air. Using a digital single-lens reflex (DSLR) camera, corona discharge light patterns were captured from the corona initiation to the gap breakdown. The resultant corona light discharge patterns were compared according to electrode type, voltage type, and voltage level. Also, corona discharge pulses were investigated using a high-frequency current transformer (HFCT) or a shunt resistor, and an acoustic sensor measured the sound levels generated by corona discharges. The light intensities of corona modes, corona inception voltages (CIVs), and extinction voltages were identified via a corona camera. The key motivations of this study are to create a dataset of corona light patterns for different electrodes at various voltage levels and to conduct a severity analysis using these images. In addition, the study shows the practicability of digital cameras for corona discharge detection compared with costly corona detection equipment, such as corona cameras, and the inability of the other sensors to identify some corona discharge modes.