Study on corona loss characteristics of two types of 8 bundle conductors at an altitude of 4300m

Corona loss is an important factor in the construction of ultra-high voltage (UHV) alternating current (AC) transmission lines. There is little research on the corona loss associated with multiple bundle conductors for UHV AC projects situated at altitudes exceeding 4000 m. To address this gap, this paper conducted a study at the Yangbajing Experimental Base in Tibet at an altitude of 4300m. Utilizing a large UHV corona cage and an integrated photoelectric corona loss measurement system, the study investigated the corona loss characteristics of two types of 8-bundle test conductors under dry, heavy rain, and wet conditions. The investigation yielded corona loss values under varying field strengths and analyzed the impact of rainfall and field strength on conductor corona losses at extreme altitudes. Subsequently, by taking the 1000 kV UHV AC single circuit transmission project as an example, the equivalent method of corona loss was employed to evaluate the corona loss of transmission line conductors at an altitude of 4300 m. The research results can serve as a reference for the construction of UHV AC transmission lines in extremely high-altitude areas of China.