现场环境下弓网离线放电辐射测量方法

为了在现场有噪情况下准确测量动车组弓网离线放电引起的辐射发射,提出了一种基于稀疏分解的瞬态电磁信号提取方法。结合弓网离线放电辐射信号波形非对称衰减的时域特征,构建了一种改进的Gabor原子库,在Gabor原子库的基础上,通过引入不对称参数和衰减参数建立了一个非对称高斯模型,使改进的原子库在时域上更符合弓网离线放电辐射信号的不对称包络和不同衰减率特性。基于改进的原子库,对弓网离线放电辐射信号进行稀疏重构提取,实现现场条件下弓网离线放电辐射地精确测量。模拟与实测实验表明,该方法能有效抑制传统Gabor原子库稀疏分解的预回波现象,重构精度更高;窄带干扰下该方法的去噪能力比基于经验模态分解(EMD)理论的去噪方法高17 dB左右,恢复出的瞬态信号与原信号误差在3 dB以内。

In situ measurement method for radiation of pantograph arcing

In order to accurately measure the radiated emission caused by the pantograph arcing of EMU in the presence of environment electromagnetic noise, a transient electromagnetic signal extraction method based on sparse decomposition is proposed. Based on the Gabor atom library, an asymmetric Gaussian model is established by introducing an asymmetric parameter and an attenuation parameter, which makes the improved atom library more consistent with the asymmetric envelope and different attenuation rate characteristics of the pantograph arcing radiation pulses in the time domain. Based on the improved atomic library, the pantograph arcing signal is reconstructed by the sparse decomposition, thus realize the accurate measurement of pantograph arcing radiation. Simulation and laboratory experiments show that the method can effectively suppress the pre-echo phenomenon in the sparse decomposition based on traditional Gabor atomic library, and the reconstruction accuracy is higher;the denoising capability of the method under narrow-band interference is about 17 dB higher than the denoising method based on EMD theory, and the error between the recovered transient signal and the original signal is within 3 dB.