Corona onset gradient of the bundle conductor on AC power lines under sand and dust weather condition at 2,200 m altitude

During spring and autumn, sand storms occur frequently in high-altitude areas of Northwest China. The presence of sand particles may affect the corona characteristics of the bundle conductor on AC power lines. A simulation system of sand and dust weather conditions was established to investigate the corona characteristics of 23 types of bundle conductors in Ping'an County (elevation 2200 m). By using tangent method, the corona onset gradient (COG) was obtained for the first time. Finally, the prediction formula for the COG was proposed considering the sub-conductor radius, bundle number, sand and dust concentration, and sand particle size.