空气湿度对导线电晕起始电压的影响

Influence of Humidity on Conductor Corona Onset Voltage

我国特高压工程中,输电线路要经过山地、湖泊等高湿度地区,空气湿度对架空输电线路电晕放电有较大影响。为研究湿度对导线电晕放电的影响,利用同轴线-筒电极研究了不同大气湿度对交流以及直流正负极性电晕起始电压的影响规律。试验结果表明:湿度对直流正极性电晕起始电压影响较小,而对直流负极性以及交流电压电晕起始电压影响较大:在相对湿度达50%～60%时,直流负极性与交流起晕电压最高。分析认为,空气湿度对空间电荷分布的影响以及湿度对导线表面状态的影响是导致起晕电压变化的主要因素。

UHV transmission lines in China may cross some high humidity areas such as lakes and mountains. Air humidity has great effect on corona performance of transmission lines. In this paper, AC and DC corona onset voltage under different air humidity was studied with the line-cylinder electrode. The results show that the change of the air humidity has slight effect on positive DC corona onset voltage. But the change of the air humidity has an obvious effect on AC and negative DC corona onset voltages. The AC and negative DC corona onset voltages are highest when the relative air humidity is about 50%-60%. The influences of humidity on space charge distribution and the rough rate of the electrode surface are the main reasons that may cause the corona onset voltage changes with air humidity.