HVDC/GIC型直流偏磁的差异性分析

考虑到地磁感应电流(geomagnetically induced current, GIC)具有低频性，过去一直将其近似等效为高压直流输电(high voltage direct current, HVDC)诱发的不平衡电流进行研究。然而，与HVDC型直流偏磁相比，GIC型直流偏磁具有显著的随机性与时变性，因此简单地将两者完全等效处理并不合理，在特定场景下应加以区分。为此，首先，从理论上分析了两种类型直流偏磁在诱发原因及特点上的差异。其次，通过研究直流偏磁对变压器本体以及电流互感器的不利影响，进一步探究两种类型直流偏磁对电网一/二次设备的影响差异，为后续的偏磁治理提供有效参考。最后，基于PSCAD/EMTDC仿真平台搭建了等效仿真模型，并通过仿真验证了理论分析的正确性。

Difference analysis of HVDC/GIC type DC bias

Considering that geomagnetically induced current (GIC) has low frequency, it has been approximately equivalent to the imbalance current induced by high voltage direct current (HVDC). However, compared with the HVDC-type DC bias, the GIC-type DC bias has significant randomness and time-varying, so it is not reasonable to simply treat the two as completely equivalent, and they should be distinguished in specific scenarios. For this reason, first, the differences in the induced causes and characteristics of the two types of DC biases are analyzed theoretically. Second, by studying the adverse effects of DC magnetic bias on transformer body and current transformer, the differences of the influences of the two types of DC magnetic bias on primary/secondary equipment of power grid are further explored to provide effective reference for subsequent magnetic bias treatment. Finally, an equivalent simulation model is built based on the PSCAD/EMTDC simulation platform, and the correctness of the theoretical analysis is verified by simulation. This work is supported by the General Project of National Natural Science Foundation of China (No. 51877088).