Geomagnetically induced currents (GIC) are a phenomenon well known for its negative effects on the operations of power systems. To efficiently mitigate them requires different types of power system modeling, from GIC to alternating current harmonic generation, to three-dimensional finite element models of transformers. GIC are initiated by variations of the geomagnetic field in the presence of the conductive Earth, that is, the geophysical variables characterized by continuous frequency spectra, making GIC also exhibit continuous spectra. In order to adequately estimate their variations and peak values for mitigation purposes, an analysis is required of how sampling rate and spectral frequency content impact the measured characteristics of GIC and harmonics. The study is based on the geomagnetic measurements and the power network data (i.e., GIC and harmonics) with high sampling rates recorded during two geomagnetic storms, March 31, 2001 and July 26–27, 2004. Availability of data covering both the source and the result of geomagnetic storm impacts on power grid allows (a) analysis of the influence of spectral content on adequate representation of both geomagnetic and geoelectric variations during the intervals with significant increases in GIC and harmonics and (b) identifying the sampling rate sufficient to usefully represent the network response presented as GIC and harmonics variations. In summary, the adequate sampling rate is suggested and the deficiencies associated with undersampling of the geoelectric and GIC variations are identified and discussed.

中文翻译：

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GIC 应用中的频率注意事项

地磁感应电流 (GIC) 是一种众所周知的现象，它对电力系统的运行产生负面影响。为了有效地减轻它们，需要不同类型的电力系统建模，从 GIC 到交流谐波生成，再到变压器的三维有限元模型。GIC 是由导电地球存在时地磁场的变化引起的，即以连续频谱为特征的地球物理变量，使得 GIC 也表现出连续的频谱。为了充分估计它们的变化和峰值以用于缓解目的，需要分析采样率和频谱频率内容如何影响 GIC 和谐波的测量特性。该研究基于地磁测量和电力网络数据（即，GIC 和谐波）在 2001 年 3 月 31 日和 2004 年 7 月 26-27 日两次地磁暴期间记录的高采样率。在 GIC 和谐波显着增加的间隔期间，频谱内容对地磁和地电变化的充分表示的影响，以及 (b) 确定采样率足以有效地表示作为 GIC 和谐波变化呈现的网络响应。总之，建议采用适当的采样率，并确定和讨论与地电和 GIC 变化欠采样相关的缺陷。涵盖地磁风暴对电网影响的来源和结果的数据的可用性允许 (a) 分析频谱内容对充分表示 GIC 和谐波显着增加的间隔期间地磁和地电变化的影响和 (b ) 确定采样率足以有效地表示以 GIC 和谐波变化形式呈现的网络响应。总之，建议采用适当的采样率，并确定和讨论与地电和 GIC 变化欠采样相关的缺陷。涵盖地磁风暴对电网影响的来源和结果的数据的可用性允许 (a) 分析频谱内容对充分表示 GIC 和谐波显着增加的间隔期间地磁和地电变化的影响和 (b ) 确定采样率足以有效地表示以 GIC 和谐波变化形式呈现的网络响应。总之，建议采用适当的采样率，并确定和讨论与地电和 GIC 变化欠采样相关的缺陷。