交流线引起同塔的嵌入式直流工频感应及直流偏磁研究
赵继超1，李金科1，田清2
(1 中国能源建设集团江苏省电力设计院有限公司，江苏 南京 211102；
2 东南大学 艺术学院，江苏 南京 211189)
摘 要：针对交流线引起同塔的嵌入式直流工频感应及直流偏磁问题，分析了直流线路上工频感应电流的等值回路和检修状态下交流线路上工频感应电流等值回路的差异，探讨了 LCC 换流站直流侧工频阻抗的等值方法，给出了直流线路上工频感应电流的简化计算方法。以江苏扬州—镇江 ±200 kV 嵌入式直流输电工程为例，计算其直流线路上产生的工频感应电流，研究交直流线路同塔架设对 LCC 换流变直流偏磁的影响。结果表明，简化计算法与详细建模法感应电流计算值接近，采用简化计算工程上是可行的；嵌入式 LCC 换流站直流侧工频等值阻抗与直流线路工频阻抗相比具有相同的数量级，忽略 LCC 换流站阻抗将使工频感应电流计算值偏大；交直流线路同塔长度越长，换流变直流偏磁越严重，交流线路换位和加装工频阻波器均可显著降低换流变直流偏磁电流。
关键词： 交直流输电；嵌入式直流；电磁感应；直流偏磁
中图分类号：TM726 文献标识码：A 文章编号：1007-3175(2025)08-0024-06
Research on Embedded DC Frequency Induction and DC Bias
Caused by AC Lines in Same Tower
ZHAO Ji-chao1, LI Jin-ke1, TIAN Qing2
（1 Jiangsu Electric Power Design Institute Co., Ltd, China Energy Engineering Group, Nanjing 211102, China;
2 School of Art, Southeast University, Nanjing 211189, China）
Abstract: For the issues of embedded DC frequency induction and DC bias caused by AC lines in the same tower, this study analyzes the differences between the equivalent circuits of AC-induced currents on DC lines and those on AC lines under maintenance conditions. It explores the equivalent methods for the AC frequency impedance on the DC side of LCC converter stations and proposes a simplified calculation approach for AC-induced currents on DC transmission lines. Taking the ±200 kV embedded DC transmission project from Yangzhou to Zhenjiang in Jiangsu province as an example, the power frequency induced current generated on the DC line is calculated, and the influence of the AC and DC lines installed on the same tower on the LCC converter transformer’s DC polarization of is studied. The results indicate that the simplified calculation method and the detailed modeling method have similar induced current calculation values, and adopting the simplified calculation method is feasible in engineering. The DC-side power frequency equivalent impedance of embedded LCC converter stations is in the same order of magnitude as the power frequency impedance of DC lines. Neglecting the converter station impedance will lead to overestimation of power frequency induced current calculations. The longer the same tower length of AC/DC lines, the more severe the DC bias magnetization becomes in converter transformers. Both AC line transposition and installation of power frequency traps can significantly reduce DC bias currents in converter transformers.
Key words: AC/DC transmission; embedded DC; electromagnetic induction; DC bias
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