| 引用本文: | 谢昱韬,林 圣,范浩然,王爱民.地铁杂散电流影响下的电流互感器传变特性分析[J].电力系统保护与控制,2026,54(01):17-27.[点击复制] |
| XIE Yutao,LIN Sheng,FAN Haoran,WANG Aimin.Analysis of the transfer characteristics of current transformers under the influence of metro stray currents[J].Power System Protection and Control,2026,54(01):17-27[点击复制] |
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| 摘要: |
| 我国直流地铁系统大多采用钢轨进行回流，因钢轨对地无法实现完全绝缘，部分回流电流泄漏将形成杂散电流。杂散电流入侵城市电网将导致电磁式电流互感器传变误差增大，甚至造成铁芯饱和、二次电流畸变等不利影响。现有研究普遍基于恒定直流影响下的电流互感器传变特性展开分析，并不能准确刻画杂散电流低频正负交变、随机波动的特性以及其对电流互感器传变特性的影响。因此，将杂散电流等效为直流与各低频分量的叠加；结合电流互感器等效电路模型建立微分方程组，推导了电网暂稳态下杂散电流对电流互感器传变特性的影响机理、影响规律及影响因素，并通过仿真分析进行对比验证。结果表明，杂散电流长期作用将引发电流互感器直流偏磁，增大一、二次侧电流幅值差与相角差。杂散电流频率越低、幅值越大，电流互感器饱和程度越深，二次侧电流畸变越严重。 |
| 关键词: 地铁杂散电流 直流偏磁 电流互感器 传变特性 |
| DOI：10.19783/j.cnki.pspc.250394 |
| 投稿时间：2025-04-12修订日期：2025-10-08 |
| 基金项目:国家自然科学基金项目资助(U2166212) |
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| Analysis of the transfer characteristics of current transformers under the influence of metro stray currents |
| XIE Yutao1,LIN Sheng1,FAN Haoran1,WANG Aimin2 |
| (1. School of Electrical Engineering, Southwest Jiaotong University, Chengdu 611756, China; 2. School of Electrical
Engineering and Electronic Information, Xihua University, Chengdu 611039, China) |
| Abstract: |
| In China, most DC metro systems utilize steel rails for current return. Because complete insulation between the rails and the ground cannot be achieved, part of the return current leaks and forms stray currents. When stray currents intrude into urban power grids, they can increase the transfer errors of electromagnetic current transformers (CTs) and may lead to core saturation and secondary current distortion. Existing studies generally analyze CT transfer characteristics under constant DC influence, which cannot accurately characterize the low-frequency alternating and randomly fluctuating nature of stray currents, nor their impact on CT transfer characteristics. Therefore, this paper models stray currents as the superposition of DC and multiple low-frequency components. By establishing differential equations based on the CT’s equivalent circuit model, this paper derives the mechanisms, patterns, and influencing factors of stray currents on CT transfer characteristics under both transient and steady-state conditions, which are further cross-validated through comparative simulations. The findings indicate that long-term exposure to stray currents induces DC bias in CTs, increasing the amplitude and phase angle discrepancies between the primary and secondary currents. The lower the frequency and the larger the amplitude of the stray current, the deeper the CT core saturation and the more severe the distortion of the secondary current. |
| Key words: metro stray currents DC bias current transformer transfer characteristics |
