直流电压下尖板电晕放电及其声特性试验分析

Experimental Analysis of Corona Discharges and Sound Characteristics of Needle-plane Electrodes Under DC Voltage

为分析特高压输电线路电晕放电产生可听噪声的机理,开展了直流电压作用下单点电晕放电的试验分析,测量并分析了脉冲放电产生的声压信号及其特征。采用尖-板电极研究了单点直流电晕放电的幅频特性,获得了不同电压(0～35kV)、不同间隙(6～8cm)及不同极性下的放电电流波形及放电图片。研究表明,直流电晕放电由一系列单个的放电脉冲组成,脉冲上升沿与脉宽主要分别集中在10ns、30ns附近;单个放电脉冲的幅值、重复率随直流电压的增加而增加,放电重复性随直流电压的增加而变差,且放电有一定的随机性。根据尖板直流电晕放电的特点,搭建脉冲放电回路来模拟不同条件的电晕放电,以实现电晕放电参数的可控性。利用传声器在消声室测量了单次脉冲放电产生的可听噪声,初步获得了放电电压和声压之间的关联特征:随着放电电压增加,声压线性增加。

In order to analyze the mechanism of audible noise on UHV transmission lines,experiments of single point corona discharge under DC voltage was developed and the sound pressure produced by pulsed discharges was measured.Based on needle-plane electrodes,the amplitude and frequency characteristics of single point corona discharge were studied,and the discharge current waveforms and discharge pictures under different voltages（0-35 kV） in different spaces（6-8 cm） with different polarities were obtained.The results indicate that the DC corona discharges are composed of a series of pulsed discharges,of which the rising edge and pulse width of single pulsed discharge are mainly 10 ns and 30 ns,respectively.The amplitude and repetitive frequency of single pulsed discharge increase with DC voltage,but the discharge parameters have some randomization and the repetition of pulses turns worse with increasing DC voltage.Moreover,based on the features of single point corona discharges,a pulsed discharge circuit was set up to simulate different corona discharges to keep the discharge parameters controllable.By using capacitor microphone,the sound pressure produced by pulsed discharges was measured in an anechoic chamber,and the correlation features between discharge voltage and sound pressure were preliminarily obtained： sound pressure increased linearly with discharge voltage.