Analysis of sound characteristics produced by high voltage discharges under DC and pulsed voltages

The mechanism of audible noise caused by corona discharge of UHV transmission lines is not well resolved. The sound characteristic produced by discharge is the foundation to analyze the intrinsic relation of audible noise and corona discharge. The experiment of sing point corona discharge under DC voltage was developed and the sound pressure produced by corona discharge was measured. The sound pressure in time domain was measured by capacitor microphone. The research results indicate the corona discharges in DC voltage are composed of a series of single discharge pulses. The rising edge and pulse width of single discharge pulse have relation to discharge voltage and electrode polarity. The corona discharge produces the sound pressure with a microsecond pulse lagging behind the single discharge pulse in their waveforms. The time delay between current pulse and sound pulse is mainly caused by sound propagation time from discharge spot to measurement spot. The nanosecond pulsed discharge platform was set up to study the relation of discharge parameter and sound characteristic. The sound pressure waveforms in different discharge parameters were obtained. Experiment results showed that pulsed discharge produce the similar sound pressure with corona discharge. The pulsed discharge platform could be used to study the mechanism of audible noise caused by corona discharge.