Study on negative corona characteristics at different altitudes

With the rapid development of UHV DC transmission projects, a large number of transmission lines need to cross high altitude areas. The reduction of corona inception field strength in high altitude areas makes corona discharge more intense. The resulting electromagnetic environment problems such as audible noise and radio interference are one of the key factors restricting the development of UHVDC transmission projects. In order to study the influence of altitude on the corona effect of negative conductor, four different altitude points in the range of 1120m-4320m were tested by using mobile small corona cage. The current pulse, audible noise and radio interference level of 0.8mm diameter fine copper conductor were collected. Through the analysis of the experimental data, the following conclusions are obtained: with the increase of altitude, the amplitude and number of current pulses increase. The audible noise and radio interference levels increase with the increase of altitude. The conclusions obtained in this paper have certain reference significance for the control of electromagnetic environment of UHVDC transmission project.