采用HHT变换方法对线缆耦合雷电波特性的分析

Research on the Features of Lightning Electromagnetic Wave Coupled with Cable Based on HHT

线缆耦合雷电波形成感应电压会给电力设备带来损害。使用希尔伯特黄变换（Hilbert-Huang transform，HHT）对室外线缆耦合的近距离云闪辐射的电磁波进行分析。结果表明：线缆耦合的云闪辐射雷电波呈阻尼振荡，其频谱主要集中在2 μs内。通过HHT变换，线路耦合的雷电波能量主要集中在1.65-3.2 MHz和3.5-6.5 MHz，而使用FFT变换得到的线缆耦合的能量集中在5-9 MHz。与FFT相比，HHT变换得到的频谱结果更详细，因此适合分析线缆中耦合的雷电波。

To explore the overvoltage frequency domain features caused by lightning electromagnetic wave （LEMW） coupled with overhead line, an experimental installation to receive the intra-cloud lightning is installed outdoors. In this paper, the Hilbert-Huang Transform （HHT） is used to analyze the electromagnetic wave coupled with cable. The results show that the lightning electromagnetic wave coupled with cable appears in damped oscillation and the spectrum concentrates in 2 μs. The energy of lightning electromagnetic wave by HHT concentrates in 1.65-3.2 MHz and 3.5-6.5 MHz, which is different from the 5-9 MHz by FFT. Compared with the results by FFT, the HHT, giving the more detailed spectrum, is more suitable for analyzing LEMW coupled with cable.