南京地磁台地铁干扰特征分析与抑制处理

地铁运行时产生的漏电流而形成的附加磁场会对附近的地磁观测造成严重干扰。通过对地铁供电系统的模拟分析得出了地铁干扰的一些基本特征。选取了2008年5月1日到30日南京地磁台受地铁干扰的日变数据和泉州参考地磁台日变数据，利用Welch功率谱估计法进行功率谱对比分析，发现地铁干扰主要对地磁场的Z分量、D分量的功率谱的高频部分造成影响，并且影响的频带范围几乎一致，主要集中在0．004-0．03Hz范围，而对H分量的影响比较微弱。在此基础上，通过小波变换对受干扰数据的Z分量和D分量进行干扰抑制处理，处理结果表明该方法能够有效抑制地铁造成的地磁场干扰。因此本文研究也提供了地磁台站干扰抑制的一种方法。

The characteristic analysis and inhibition of the MTR disturbance imposed on Nanjing Geomagnetic Station

Magnetic field generated by leakage current of DC electrified railways（MTR） may cause serious disturbance to the geomagnetic observation of the nearby stations. Via simulation analysis on the power supply system of the MTR we get some basic characteristics of the MTR disturbance. In this paper, we choose diurnal variation data from Nanjing and Quanzhou stations in May 2008 to make comparative analysis, the power spectral analysis by Welch power spectrum estimation method shows that the MTR disturbance mainly impacts the vertical（Z） component and deviation（D） component in the High frequency band unanimously, especially in the bandwidth of 0. 004-0.03 Hz, and that it has relatively weaker impact on the horizontal（H） component. On this basis, we apply the Wavelet Transformation （WT） approach to inhibit the MTR disturbance imposed on the Z-component and D-component of Nanjing station, the preliminary results show that the WT method can effectively inhibit MTR disturbance, which suggests that the method provided in this paper may also useful for the inhibition of geomagnetic disturbance.