Impact of Icing Severity on Positive Corona Generated Audible Noise Characteristic of Rime Ice-Covered Conductor

This research studies the impact of icing severity on audible noise (AN) characteristics of a rime ice-covered smooth conductor. The conductor is energized with positive polarity voltage during artificial icing experiment and corona performance experiment. The experiments are performed in a corona cage located in an artificial climate chamber. Test results show that harsher icing severity causes higher AN and the AN approaches saturation. The empirical formula for different icing severities is also given, which can help predict the AN, once the icing thickness and nominal electric field intensity are given. The studies of the one-third octave band spectra indicate that the audio frequency can be divided into three sections: background noise section, transitional section, and corona discharge section. The A-weighted AN is independent of the frequency components in the background noise section. However, in the corona discharge section, the differences between A-weighted AN and frequency components are constant once the frequency component is designated. Especially, the 3.15-kHz component is recommended to extract the corona-generated AN during the long-term AN monitoring, and its relative error is less than 3.6%.