Characteristic analysis and treatment of Shanxi geomagnetic array interfered by ground pole of HVDC transmission on Jinnan line

In September 2014, Shanxi Earthquake Agency and the Institute of Geophysics, China Earthquake Administration jointly completed the construction of the geomagnetic station array in the Hengshan fault zone in the north of Shanxi. The geomagnetic station array is composed of 5 GM4 type fluxgate magnetometers, which are respectively installed in Daixian, Shanyin, Yingxian, Fanchi and Huairen to obtain the three-component magnetic field data in the observation area. The 5 measurement points of the geomagnetic station array are located near the grounding electrode of the Jinnan line of high-voltage direct current transmission. By comparing the GM4 type fluxgate magnetometer at the 5 measurement points of the geomagnetic station array with the geomagnetic second data of other stations, the interference amplitude of the high-voltage direct current transmission line (Jinbei-Nanjing) on the geomagnetic data of the Shanxi geomagnetic station array was measured, correlation and error analysis also were carried out, and the fitting formula was obtained. The results show that the variation amplitude of the Z component disturbed by the Jinnan line high-voltage direct current transmission in the Shanxi geomagnetic station array decreases as the vertical distance from the station location to the Jinnan line increases, and the interference amplitudes of the H and D components are linearly correlated with the interference amplitude of the Z component. Taking the variation of the Z component as the dependent variable, using the reference fitting formula to obtain the variation of the H and D components can be applied to the daily processing work of the magnetic field interference of the Shanxi geomagnetic station array under the influence of the Jinnan line high-voltage direct current transmission.