Wideband and Narrowband HVDC Conductor Corona Test Methods for Radio Noise Prediction

Various conductor corona test methods have been used to predict corona performance of HVAC transmission lines. Due to the formation and build-up of space charge, it is unclear whether the same methods can be used for corona performance of HVDC conductors. We investigate the use of a large corona cage, a short test line, and a small corona cage at high altitude to generate RI data. Wideband excitation functions are derived using time- and frequency-domain techniques. These generation functions are compared to CISPR standard narrowband measurements as well as published empirical RI prediction formulas. We find that a small corona cage cannot be used to accurately predict the RI performance of HVDC transmission lines at high altitude.