Statistical characteristics and stochastic model of DC corona-generated sound pressure pulses from single corona source

The sound pressure level (SPL) has been generally accepted in the measurement and evaluation of degree of nuisance to the corona-generated audible noise from transmission lines. Quite many scholars have studied the spectrum and statistical characteristics of the SPL from transmission lines through the long-term frequency measurement. In fact, the corona sources on the transmission lines usually act as sound sources emitting sound pressure pulses with random amplitudes and random time intervals, yet the statistical characteristics of the random sound pressure pulses and their correlation to the SPL have barely been investigated. In this paper, a series of experiments with single positive corona source in a coaxial cylindrical structure were carried out to investigate the statistical characteristics of the pulse amplitudes and time intervals of sound pressure pulses. In the experiment, time-domain measurement for the audible noise was employed. Based on the statistical results, a stochastic model was developed to simulate the sound pressure pulses. The validity of the stochastic model was testified by comparing the simulated and measured A-weighted sound pressure levels. On the basis of the stochastic model, the influence of random pulse amplitudes and time intervals of the sound pressure pulses on the resultant SPL was demonstrated.