The influence of dust particles on the DC breakdown voltage of rod-rod air gaps

Abstract

The rod-rod gap has been adopted by the IEC as a mean of measurement of direct voltages in HVDC transmission. However, its performance, in areas where dust suspension in air is a common meteorological characteristic, is not known. This paper investigates the influence of dust particles on the positive and negative DC breakdown voltage of rod-rod air gap clearances for voltages up to /spl sim/ 250 kV. It is shown that dust particles can have a serious effect on direct voltage breakdown characteristics of such gaps. Some prebreakdown discharge studies related to these effects are also presented.