Corona Onset Characteristics of the 750-kV Bundle Conductor in Sand and Dust Weather in High-Altitude Area

In high-altitude areas of Northwest China, sand and dust weather is frequent, which may have an influence on the corona onset characteristics of the bundle conductors of the 750-kV power transmission lines. So the corona resistive currents of the used conductors of the 750-kV power transmission lines were measured based on the movable corona cage in fine and simulated sand and dust weather in Xining City, Northwest China, and the altitude of the test spot is 2200 m. The corona onset electric-field strength was gained according to the IEEE definition. The test result shows that compared with the no sand weather, the corona onset electric-field strength decreases in the sand and dust weather. When the sand concentration and sand particle size increase, the corona onset electric-field strength decreases accordingly. With further analysis, the roughness factor decreases with the increase of the sand concentration and sand particle size.