Experimental research on influences of air pressure and humidity on characteristics of streamer propagation along insulation surfaces

At present, most of the UHV transmission lines, under construction and planning, will pass the high altitude area. The complex weather conditions along the transmission lines will make the insulation condition of the transmission lines and electrical equipment face the ordeal. Therefore, it is necessary to study the influence of air pressure and humidity on characteristics of flashover along the insulation surfaces. The research results will provide a theory basis for the insulation design of the UHV transmission lines. In the paper, the influence of environment factors (air pressure and humidity) on characteristics of flashover along the insulation surfaces was discussed through inquiring into the mechanism of streamer discharge. In three-electrode arrangement, the characteristics of streamer propagation along insulation surfaces under the different air pressure and humidity were measured by photomultipliers. The test results show that the streamer stability propagation field is in proportion to air pressure or humidity. Under the same electric field, the streamer propagation velocity or streamer luminous intensity is in inverse proportion to air pressure or humidity. Therefor, It is easier for streamer propagation in the lower air pressure and humidity. The streamer stability propagation field is lower, under the same electric field, the streamer propagation velocity or streamer luminous intensity is higher. © 2014 Chin. Soc. for Elec. Eng.