In a voltage-source converter dc grid, a dc fault current limiter (FCL) is a key apparatus. When faults occur, it is supposed to effectively and immediately suppress transient short-circuit current to protect other equipment, e.g., converters. Additionally, it is required to bring as little negative effect as possible under normal operation. Although the respective advantages are highlighted in different FCLs, one or two key disadvantages can significantly decrease the overall performance. In this article, a novel magnetic coupling FCL (MCFCL) is proposed and achieves a good balance among its advantages and disadvantages. An MCFCL consists of a mutual inductor and some power electronic switch modules. The mutual inductor metallic primary winding is connected in series to the transmission line and magnetically coupled with the secondary winding. The secondary side impedance is controlled by the power electronic switch modules. The novel 4-segment model is proposed to demonstrate the current-limiting physics, formulate the current-limiting effect, and support the design. One medium voltage (10 kV) case study is carried out based on the numerical simulation. The MCFCL shows a better current-suppressing effect and a lower impedance under normal operation than the benchmark Reactor FCL. Finally, this article is validated on a scaled-down experimental facility.

中文翻译：

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VSC直流电网新型磁耦合故障限流器的拓扑建模与设计

在电压源转换器直流电网中，直流故障限流器 (FCL) 是关键设备。当故障发生时，应立即有效抑制瞬态短路电流，以保护其他设备，如转换器。此外，还要求在正常运行的情况下尽可能减少负面影响。尽管在不同的 FCL 中突出了各自的优势，但一两个关键劣势会显着降低整体性能。在本文中，提出了一种新型磁耦合 FCL (MCFCL)，并在其优点和缺点之间取得了良好的平衡。MCFCL 由互感器和一些电力电子开关模块组成。互感器金属初级绕组与传输线串联并与次级绕组磁耦合。二次侧阻抗由电力电子开关模块控制。提出了新颖的 4 段模型来演示限流物理、制定限流效果并支持设计。基于数值模拟进行了一个中压 (10 kV) 案例研究。与基准 Reactor FCL 相比，MCFCL 在正常操作下显示出更好的电流抑制效果和更低的阻抗。最后，本文在缩小的实验设备上得到验证。与基准 Reactor FCL 相比，MCFCL 在正常操作下显示出更好的电流抑制效果和更低的阻抗。最后，本文在缩小的实验设备上得到验证。与基准 Reactor FCL 相比，MCFCL 在正常操作下显示出更好的电流抑制效果和更低的阻抗。最后，本文在缩小的实验设备上得到验证。