城市轨道交通供电系统在一座主变电所支援供电运行方式下运行，供电电缆较长，电缆的对地电容与主变压器漏感可能发生谐波参数匹配，放大系统内的背景谐波，引发谐振。本文以某市1号线地铁供电系统调试期间发生的一起11次谐波谐振事故为背景，搭建谐振电路模型，分析了城市轨道交通供电系统谐波谐振产生原因，即系统背景中的11次谐波被供电电缆对地分布电容和主变压器漏感构成的并联回路放大，分析结果与现场记录数据一致。同时，本文提出采取前期工程设计计算系统谐波阻抗参数，严格限制背景谐波含量满足规范要求，评估整流器生产工艺，以及明确SVG滤波功能等措施来提高供电系统抑制谐波的能力。

When the Urban transit power supply system (UTPSS) operates in the power supply mode supported by only one main substation, the power supply cable is long. It can result in the harmonic parameter matching between the ground-to-ground capacitance of the cable and the main transformer leakage inductance which may amplify the background harmonics in the system. Based on a UTPSS resonant accident occurred during the commissioning of the subway of Line 1 in a city, this paper builds a resonant circuit model and analyzes the reason of the harmonic resonance of this UTPSS. More specifically, the resonance is originally generated by 11th background harmonic and amplified by the parallel circuit consisting of the ground-to-ground capacitance of the cable and the main transformer leakage inductance. The analysis result is consistent with the field recorded data. Meanwhile, this paper puts forward several measures to suppress resonance of the UTPSS in subway: calculate the harmonic impedance parameters in the preliminary engineering design stage, strictly limit background harmonics to meet requirements, evaluate converter manufacturing technique, and confirm the filter functions of SVG.

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