Radio interference of Ultra HVDC transmission lines in high altitude region

Corona phenomenon of Ultra High Voltage DC in high altitude region is more serious, and corresponding electromagnetic environment is more severe as well. Radio Interference is the most important consideration during the design and operation. Characteristics of RI and its influence factors were studied based on an UHVDC test line with an altitude of 2100 m in the National Engineering Laboratory for UHV Technology, located in Kunming, China. The measuring system of RI long term tests was introduced. Lateral and longitudinal distribution and spectrum of RI near the transmission line were analysed at various voltages, weather conditions.