Analysis of the influence of specific humidity on positive streamer predischarges considering h/δ greater than 15 g/m/sup 3/

Abstract

The humidity correction factors specified by IEC Publication 60-1 (1989) and IEEE Std.4 (1995) for impulse voltages are restricted to 1 2 h/6 < 15. However, values of h/S 2 15 g/m3 in many regions of the world are present. The IEC-60 and the IEEE Std.4 procedures are based on the macroscopic observation that the atmospheric correction factors are larger when the discharge is governed mainly by positive streamers;while they tend to be lower when leaders or negative streamers are present. A better atmospheric correction factor implies to study the influence of atmospheric parameters on each discharge mechanism of the breakdown process. In this paper for standard lightning impulse voltages an analysis of the influence of absolute humidity divided by relative air density (his) greater than 15 gr/m3 on the positive streamer predischarges is reported.

Positive Switching Impulse Discharge Performance and Voltage Correction of 1 meter Rod-plane Air Gap

“…Reference [19] points out that humidity has little influence on discharge voltage, just within 2%. However, the specific humidity influence becomes stronger at the same absolute humidity, for the bigger value of h16 (>15 g/m3) at high-altitude areas, according to [20].…”