Corona Discharge Characteristics and Size Optimization of Large Fittings for Ultra-High Voltage Transmission Lines up to 4800 m

With the rise of the carbon neutrality strategy, there has been a global push to harness clean energy sources such as solar, wind, and hydropower, which are often located in remote areas from central cities. Long-distance transmission lines traverse various complex terrains, potentially crossing regions in China with altitudes ranging from 0 to 4800 m. In this context, this paper focuses on studying the corona inception characteristics of large transmission line fittings at different altitudes. Firstly, the corona characteristics of transmission line fittings at altitudes of 60 m and 4350 m are examined. The study obtained corona inception electric field characteristics for fittings with different type and size. Additionally, to understand the corona inception characteristics of fittings at intermediate altitudes, simulated altitude tests were conducted in an artificial climate laboratory. Based on these experimental results, this study provides recommended fitting parameters for transmission lines at various altitudes. Furthermore, considering that transmission towers, especially tension towers with special conductor structures, may exhibit increased corona characteristics due to conductor bending, the impact of jump lines on corona discharge characteristics in high altitude areas was also investigated. The series of conductor parameters obtained will benefit the construction of transmission lines in various regions globally.