Investigations of Corona Discharge Images for Rod-Rod Electrode System Under HVDC

This study presents the investigations of visual images originating from various corona discharge forms occurring under +DC and −DC voltages. The experimental setup included two hemispherical tip rod electrodes with a tip radius of 2 mm, and the gap spacing between them was set to 5 cm to observe corona discharge forms. The voltage was increased in steps, and a corona camera was used to determine the corona inception voltage. The transitions between different forms of corona discharges were observed. Images of corona discharges were taken at each voltage level using a digital single-lens reflex (DSLR) camera. Furthermore, the pulses generated by the corona discharges were examined using a high-frequency current transformer (HFCT) and a shunt resistor. The main objective of this investigation was to analyze the severity of corona discharge on the system based on the obtained corona images. Also, the usability of the HFCT and shunt resistors as measurement sensors was discussed.