Research on the Corona Inception Characteristics of AC Conductors at High Altitude Based on Ultraviolet Imagery

AC transmission lines in China have been built at high-altitude areas. Corona onset characteristics of AC conductors may be affected by altitude, and corona onset characteristics of conductors are important guidances for practical engineering construction, therefore, it is of great significance to study the corona onset characteristics of conductors at high altitude. Based on the UHV corona cage at an altitude of 2200m in Ping’an, the experimental investigation for corona inception characteristics of AC conductors at high altitude were carried out with commonly used 4, 6, 8, 10, 12 bundle conductors of LGJ400 tested and ultraviolet imager was used to observe the corona discharge intensity. In this paper, the experimental results of corona discharge intensity of LGJ400 conductors and the typical ultraviolet spectrum of corona discharge were obtained under the voltage from 0-475kV, in addition, the corona onset voltage and corona onset electric field were calculated.