Research Of Interference On Earth-magnetic Observation From DC Power Lines

Our country is in seismic activity in multiple regions, diversely geomagnetic monitoring station to forecasting and monitoring seismic activity of important tasks, through observation of the Earth magnetic field changes to monitor geological activities. Normal operation of DC transmission lines by DC magnetic field and magnetic field of the signal is not easy to distinguish, but if you change the transport current in bipolar and unipolar switch between running, or line failure in normal operation, it could lead to ten thousand square kilometres along the DC magnetic field levels of mutation. In the current DC power transmission engineering construction, how to avoid on seismic monitoring station of electromagnetic effects, has been plagued by widespread DC path selection.According to seismic geomagnetic observation of the basic principles of the main tasks and, combined with Wuhan geomagnetic observation data by station, from geomagnetic Observatory provides information to geomagnetic disturbance, to study because the DC lines run as and conveying power changes, the impact of geomagnetic observation data characteristics; according to the basic principle of geomagnetic observation and the observation instrument work, judge DC transmission lines on the basis of geomagnetic observation impact. In accordance with the structure of a DC transmission lines, DC current flow path is a line of very grounding conductor and passed into the ground. From the electromagnetic field theory, the flow of electric current will produce a magnetic field, and therefore the entire DC transmission system produces a magnetic field should be a great conductors and Earth current generated by the magnetic field overlay. But for a more in-depth study of the magnetic field produced by DC current, you must individually on a wire current and magnetic field of Earth current evaluated, discriminant DC lines on geomagnetic observation of the main factors。so as to reduce the DC lines on geomagnetic observation of theoretical support provided. Research into the magnetic field and currents, the need to consider an even layer of soil and soil; study of the magnetic field generated by the conductor current, accessible from the long straight wire, multiple root pole wire and segmented pole wire, etc.