Very low frequency (VLF) breakdown of air in non-uniform fields for varying humidity conditions

摘要

The effect of humidity on the breakdown voltage of air for frequencies in the kilo-Hertz range is largely unknown, especially for larger dimensions. This is of interest for high-power communication towers that can operate in a variety of climates. The very low frequency (VLF) and low frequency (LF) bands are used for long distance communication in the range of 10–30 kHz and 30–100 kHz, respectively. Results are reported for rod/rod gaps and rod/plane gaps in the range of 125–1000 mm at a frequency of 30 kHz. The breakdown voltage at 30 kHz is observed to be markedly lower than that at 60 Hz for non-uniform field configurations with corona pre-discharges. Electric field calculations have been completed for the experimental configurations to attempt to explain the difference in breakdown voltage.