Surface roughness effects on corona-generated radio noise for long-term operating conductors

An investigation into the effect of surface roughness on corona-generated electromagnetic interference of long-term operating conductors is presented. The surface texture and roughness of typical long-term operating conductors is measured. The radio noise measurement system based on the corona cage is developed and discussed. As a result of the rough surfaces, the corona discharge intensity of long-term operating conductors turns to be stronger than that of the new conductors. The decrease rates of the corona inception voltages between the long-term operating conductors and new conductors were found to increase linearly with the raise of surface roughness degree R_a. The deviation of radio noise between the long-term operating conductor and new conductor is found to increase linearly with the raise of R_a.