高速铁路环境电磁兼容测试场地衰减的修正

The Correction to the Site Attenuation of the EMC Test Site in High-Speed Railway Environment

根据John Berry的理论,基于特定平衡不平衡转换器的等效电路,建立测试场地的仿真模型,采用矩量法仿真计算场地衰减(SA)。将仿真计算的实际测试场地SA与理想测试场地SA的差值(ΔSA)作为修正值,用于修正实际场地的测量SA。分别仿真计算测试场地、控制室和避雷针3种影响因素单独存在和同时存在时的ΔSA。并将实际场地的仿真计算SA与测量SA进行比较。结果表明:这3种因素均对SA有影响;ΔSA的最大值达到0.74 dB;可将ΔSA用于对实际场地的测量SA的修正;仿真计算的实际场地SA结果与测量的结果基本吻合,验证了仿真计算方法的有效性。

According to the theory of John Berry,the moment method was adopted to compute the site attenuation（SA） through establishing a simulation model of a test site based on the equivalent circuit of the specific balun.The differences（ΔSA） between the simulated SA of an actual site and the SA of the ideal site was used as the correction values for correcting the measured SA on the actual site.The influences（ΔSA） of the site size,the controlling room and the lightening rods on SA were computed respectively.The integrated influence of all factors was computed too.The simulated SA of the actual site was compared with the measured SA.Results show that these three factors all have effect on SA.The maximum difference（ΔSA） is up to 0.74 dB.The computed ΔSA can be considered as the correction of the measured SA on an actual test site.The computed SA basically agrees with the measured SA of the actual site,which demonstrates the effectiveness of the proposed method.