METHOD FOR DETERMINING OF PROTECTIVE CURRENT OF MAIN LINE

摘要

The setting method of the main protecting current is based on the measuring of the magnetic field strength.The strength of the magnetic field is measured at three points, which are located in a vertical flat and the distance between which it is fixed. The flat goes through the axle of the pipe and is square with the flat.According to the strength of the magnetic field, the protective current and the potential are calculated using these formulas:Irot=4πa(H1-H2)(H2-H3)(H1-H3)/(H1+H3-2H2)<2>Urot=4aK(H1-H2)(H2-H3)(H1-H3)/Dv(H1-2H2+H3)<2>a - distance between the points, in which the strength (m) of the magnetic field is measured;H1, H2, H3 - the strength of the magnetic field at the first, second and third points (A/m);K - ferro-modulative converter coefficient (Ωm);Dv - outer pipe diameter (m).