ИСТИНА

The principle and device for registering geoinduced currents for non-contact measurement of alternating and quasidirect currents in the phase wires of overhead power lines by the differential method have been developed. The differential method for measuring the current magnetic field in power lines has been known for a long time, the earliest mention dates back to 1994, a fresh review was published in 2020. The magnetic field under the overhead line is a superposition of the Earth's magnetic field and the magnetic field of currents flowing in phase wires. To subtract the Earth's magnetic field from the currents in the overhead line, a differential method is used: measurements are made with two identical sensors, one of which is placed under the wires of the overhead line, and the second at such a distance that the influence of the line currents is negligible. When processing the data, the data from the second sensor are subtracted from the measurement results of the first sensor (the Earth's field is the same at these points). The difference in our implementation is that we use not fluxgate or quartz sensors, but solid-state two-component magnetoresistive magnetic field sensors. This choice made it possible to significantly reduce the cost of the breadboard device, as well as significantly reduce power consumption to increase the autonomy of the monitoring system. Measuring the currents in the overhead line will make it possible to estimate the linear emf excited by geomagnetic disturbances in the lines for use in model calculations. For two months of trial operation of the device, the prospects of the differential method for measuring geoinduced currents in overhead line wires were confirmed. This study is supported by the grant no. 22-29-00413 from the Russian Science Foundation (https://rscf.ru/project/22-29-00413/). Viljanen A., Pirjola R. (1994). Geomagnetically induced currents in the Finnish high-voltage power system. Surveys in Geophysics, 15(4), 383–408. doi:10.1007/BF00665999 Hübert J., Beggan C.D., Richardson G.S., Martyn T., Thomson A.W.P. (2020). Differential Magnetometer Measurements of Geomagnetically Induced Currents in a Complex High Voltage Network. Space Weather. doi:10.1029/2019sw002421