New proposal of correction factors for dc voltages

The IEC-60-1989 and IEEE Std. 4-1995 procedures for dc voltages are not suitable for high altitudes. The assumption that the streamer propagation field varies linearly with the relative air density does not apply to high-altitude dc breakdown. Recently it has been published some work related to the positive polarity, in this paper, finally, considering both positive and negative polarities a new proposal of correction factors for dc voltages is presented. It has been concluded that the effect of air density and humidity can be accounted for independently, that in positive polarity it is necessary to correct both for relative air density and for humidity, but in negative polarity only by relative air density, furthermore, a gap factor for different arrangements of electrodes is introduced.