尖端导体电晕放电辐射场的计算与实验

Calculation and Experiment of Radiation Fields from Tip Corona Discharge

为研究输电线电磁辐射问题,以尖端导体电晕放电为研究对象,利用偶极子模型和传输线模型尖端导体电晕放电辐射场进行理论计算,得出了电磁辐射信号特征;在实验室进行直流高压下尖端电晕放电模拟和实验研究,验证了理论分析的正确性。研究结果表明,电流注入导体产生的辐射场要比空气电晕区产生的辐射场强的多,在对尖端导体电晕放电辐射场的远距离探测时,空气电晕区产生的辐射场可以忽略不计;尖端导体电晕放电辐射场主要是垂直极化场,由电晕电流在导体两端来回反射引起的;信号的时域波形呈衰减振荡形式,信号的峰值随外加电压的升高而增大,正电压下信号的强度明显比负电压下信号的强度大;信号首脉冲的方向随外加电压的极性不同而相反;信号的持续时间在几百ns数量级,而且随着导体长度的增加,信号的持续时间有增大的趋势。该研究结果对于输电线电晕抑制及周围电磁环境评价具有重要意义。

To understand the electromagnetic radiation of power transmission lines, we theoretically calculated the tip conductor corona discharge radiation field by using the dipole model and the transmission line model, obtained the mechanism and the signal characteristics of the corona discharge electromagnetic radiation field, simulated and tested the tip conductor corona discharge in the lab, and verified the correctness of the theoretical analysis. The results show that the radiation field produced by the current injected into the conductor is much stronger than that in the air corona district. In the remote detection of the radiation field of tip conductor corona discharge, the radiation field generated by the air corona district can be ignored. The tip conductor corona discharge radiation field is vertically polarized field, which is caused by the corona current echo at both ends in the conductor. The time domain waveform of the signal shows a damped oscillation, the peak of the signal increases with the increasing of the applied voltage, and the strength of the positive voltage signal is significantly larger than the negative voltage. The direction of the first pulse of the signal is opposite with the different polarity. The duration time of the signal is a few hundred ns, and the duration time increases with increasing of the conductor. The results are of great significance for the transmission line corona suppression and the surrounding electromagnetic environment evaluation.