Influence of humidity on the breakdown voltage of a sphere-sphere gap,at the 2 600 M O.S.L

摘要

An investigation report of the possibleeffects of humidity on the 50% probability breakdownvoltage of a sphere-sphere gap configuration in air atthe altitude of 2 600 meters over sea level is presentedin this paper. Positive lightning impulse voltages wereapplied. The tests were carried out at the HighVoltage Test Laboratory of the Universidad Nacionalde Colombia in Bogotá, Colombia. Environmentalconditions of humidity and temperature werecontrolled. The multiple level test method MLM wasused. Additionally, 20 breakdown impulses of the lastMLM level were recorded and analyzed. Nosignificant differences in 50% probability breakdownvoltage for different values of humidity andtemperature at the test conditions were found. In the20 recorded breakdown impulses no evidence onpredisruptive events were observed. Nevertheless, theresults show that the correction factors for the relativedensity of air proposed in IEC Standard 52 and IECStandard 60-1 are not adequate for Bogotá testconditions. For this reason, correction factors for therelative air density of the experimental conditions aresuggested.