Comparative phase-resolved analysis of AC corona discharges at very low (0.1 Hz) and power frequencies

Very-low-frequency (VLF) high voltage excitation emerges as a promising alternative diagnostic tool to conventional testing at power frequency. In this paper, a comparative analysis of corona discharge in air at power and VLF frequencies is conducted under different levels of voltage excitation. Here, the discharge characteristics are presented in terms of IEC 60270 standardized parameters. Experimental results show that under VLF testing, the discharges exhibit comparatively higher average magnitude, repetition rate per cycle, current and power than testing at power frequency.