Elliptical polarization of the magnetic field of parallel currents and methods of their determination

Abstract

Determination of positions and electrical currents of underground pipelines using the electro¬magnetic method allows us to draw conclusions about the quality of the insulation of pipelines. The analysis of the spatial characteristics of the magnetic field of the low-frequency current of the pipeline is carried out on the basis of the Biot-Savard-Laplace law, which determines the dependence of the components of the magnetic field on the given current in a homogeneous, boundless space. It is shown that for two or more parallel pipelines to each other placed close, it is necessary to take into account their total magnetic field. A mathematical model of the magnetic field of parallel rectilinear alternating electric currents was developed, taking into account the phase difference between them, which leads to the emergence of an elliptically polarized total magnetic field. The methods of determining the coordinates of the currents of parallel underground pipelines are analyzed. The relation of the components of the magnetic field for different coordinates of the pipelines, currents and the phase difference between the currents was obtained. Known methods of determining the coor¬dinates and currents of parallel underground pipelines are intended for the partial case of linear polarization of the magnetic field (with in-phase or anti-phase currents). In the general case of elliptic polarization of the magnetic field, a combination of tuning and scanning methods should be used.