Analysis and Fitting of the Time-domain Waveform of the Audible Noise Caused by Single Positive Corona Source on the Conductor

The time-domain waveform of audible noise caused by the discharge of single positive corona source is obtained by the time-domain test platform set up in the laboratory. According to the pulse characteristic of time-domain waveform of audible noise it is proposed to utilize segmented double-exponential function to fit single time-domain pulse waveform of single audible noise to obtain empirical waveform, and through the comparative research on fitting results and measured results in time-domain and frequency-domain the reasonableness of the proposed method of the fitted waveform is validated. Finally, based on the measured results of long-term audible noise in time-domain the statistical characteristics of fitting parameters of the segmented double-exponential function under different voltages and that of waveform parameters of audible noise. Experimental results show that due to the randomness of corona discharge, the pulse waveform parameters and waveform fitting parameters evidently fluctuate under the same voltage; the time interval of audible noise pulse decreased with the increase of the applied voltage, however the pulse width and its apparent duration slightly varies under different voltages.