Effect of VLF/LF frequency and humidity on the breakdown of air

The paper reports the results from a study to investigate the effect of humidity and frequency on the breakdown of air. It is known from existing literature that humidity causes an increase in the breakdown voltage at power frequency (50/60 Hz), but the effect at frequencies in the very low frequency (VLF) radio range (10 kHz-30 kHz) remain largely unknown. Experiments were conducted on Rogowski-profile uniform field gaps ranging from 4 to 45 mm. Unlike at power frequency, results show that breakdown voltages have a nonlinear relationship to humidity and generally decrease with increasing humidity. The objective of this study is to determine correction factors for humidity at VLF and LF (low frequency).