Long-Term Statistical Study of the Corona Electric Field and Ion-Current Performance of a ±900-kV Bipolar HVDC Transmission Line Configuration

The corona, electric field and ion- current performnance of a 6 x 4.06-cm conductor bundle, chosen for use on a ±900-kV bipolar HVDC transmission line, was studied on a test line for a period of over 18 months. The results obtained provide a statistical evaluation of radio interference (RI), audible noise (AN), corona loss (CL), electric field and ozone generated by the line at the nominal voltage as well as furnishing data on the frequency spectra of AN and on the lateral profiles of RI, AN and ion-current density at ground level. In addition, the results were analyzed to obtain the influence of atmospheric variables such as air density, humidity and wind velocity on the corona performance characteristics and to draw conclusions about the influence of the test duration on the statistical significance of the results.