基于D-dot传感器的弓网离线放电瞬态电场时域测试方法

Time-domain measurement of the transient electric field caused by pantograph-catenary off-line discharge based on D-dot Sensor

弓网离线放电电磁辐射具有瞬态、宽频带的特性,可使用D-dot传感器对其进行时域瞬态电场测量,但在对传感器所测微分信号积分还原时,存在信号恢复失真问题严重。搭建了包含脉冲电场发生装置和测量装置的瞬态电场时域波形还原系统,开展了基于D-dot传感器的去直流、数值积分、消除趋势项以及系统辨识低频补偿在内的瞬态电场时域波形测试方法的研究,利用该方法测试了不同电压下弓网离线放电电磁辐射的电场时域波形。理论与实验结果表明:本文所提出的方法能准确、稳定地还原弓网离线放电所辐射瞬态电场的原始时域波形,还原信号与实测微分信号的主要频率分量均在7.5 MHz,二者的相关系数达到93%以上。

The electromagnetic radiation of pantograph-catenary offline discharge has the characteristics of transient and broadband.We can use the D-dot sensor to measure its transient electric field in time domain.However,the direct integral operation of the differential signal seriously distorts the original signal.To solve this problem,a transient electric field time-domain waveform restoration system including a pulse electric field generating device and a measuring device is built in the laboratory firstly.Then,we propose a time-domain waveform restoration method for transient electric field including DC removal,numerical integration,elimination of trend items and low frequency compensation.Finally,the method is used to test the electric field time domain waveform of electromagnetic radiation of pantograph-catenary offline discharge under different voltages.Theoretical and experimental results show that the proposed method can accurately and stably restore the original time-domain waveform of the transient electric field radiated by off-line discharge of the pantograph.The main frequency components of the reduced signal and the measured differential signal are both at 7.5MHz,and the correlation coefficient between them is more than 93%.