交流線引起同塔的嵌入式直流工頻感應及直流偏磁研究
趙繼超1，李金科1，田清2
(1 中國能源建設集團江蘇省電力設計院有限公司，江蘇 南京 211102；
2 東南大學 藝術學院，江蘇 南京 211189)
摘 要：針對交流線引起同塔的嵌入式直流工頻感應及直流偏磁問題，分析了直流線路上工頻感應電流的等值回路和檢修狀態下交流線路上工頻感應電流等值回路的差異，探討了 LCC 換流站直流側工頻阻抗的等值方法，給出了直流線路上工頻感應電流的簡化計算方法。以江蘇揚州—鎮江 ±200 kV 嵌入式直流輸電工程為例，計算其直流線路上產生的工頻感應電流，研究交直流線路同塔架設對 LCC 換流變直流偏磁的影響。結果表明，簡化計算法與詳細建模法感應電流計算值接近，采用簡化計算工程上是可行的；嵌入式 LCC 換流站直流側工頻等值阻抗與直流線路工頻阻抗相比具有相同的數量級，忽略 LCC 換流站阻抗將使工頻感應電流計算值偏大；交直流線路同塔長度越長，換流變直流偏磁越嚴重，交流線路換位和加裝工頻阻波器均可顯著降低換流變直流偏磁電流。
關鍵詞： 交直流輸電；嵌入式直流；電磁感應；直流偏磁
中圖分類號：TM726 文獻標識碼：A 文章編號：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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