Geomagnetically Induced Current-Monitoring Method Based on High Voltage Wires for Transformers

Hall sensors have a relatively low withstand voltage but have been used at the neutral point of transformers to monitor geomagnetically induced currents (GICs). However, when introduced into monitoring devices via sensor wiring, high voltages at the transformer neutral point can lead to damage to electronic components and increase the risk of serious power grid accidents. For monitoring GICs from the neutral point of the transformer, this paper proposes a transformer GIC monitoring method based on high-voltage wire equipotentials and a transformer GIC power (GIC-Q) algorithm based on the proportional coefficient K value method. A transformer monitoring device based on the proposed methods was tested at a 500 kV substation in China. In addition, we verified the accuracy of the proposed method and validity of the monitoring data produced using geomagnetic disturbance data with a Kp-index of 4 from the Man Zhouli Geomagnetic Observatory Station.