Analysis on the spectrum characteristic of corona Current and its relationship with Radio Interference on UHVDC transmission line

Corona current is the key parameter to characterize the corona discharge. Researches on the spectrum characteristics of corona current and the relationships between corona effects are of great significance on optimization design of Ultra High-Voltage Direct Current (UHVDC) transmission line. Basing on the corona current experimental data measured on an actual UHVDC test line, the spectrum characteristics and variation regularity of corona current within the spectrum band of 0.15-4 MHz were studied, and the correlation between energy spectrum of corona current and Radio Interference (RI) under the same conditions was also analyzed in this paper. It was found that variation regularity of logarithmic energy spectrum of corona current was remarkably similar to that of RI within 0.15-4 MHz. Basing on the conclusions above, a formula for estimating the logarithmic energy spectrum of corona current with the maximum nominal surface electric field strength of line was proposed, and the key parameters in the formula were established for a particular typed conductor which was 6-bundled. Those results not only can improve the theoretical understanding of the relationships between corona current and RI, but also provide a new method for estimating the spectrum characteristics of corona current.