Analysis of alternating magnetic field location technology of buried pipe lines

The magnetic field induced by currents flowing through the ground between a buried pipe and an earth contact electrode is analyzed and numerically evaluated under the assumptions of homogeneous soil of pure resistance and quasi-steady field in order to clarify and to increase the accuracy of alternating magnetic field location technology. An effective formula for the evaluation of the magnetic field induced by underground current is developed. The theory evaluates the magnetic field with about 80% accuracy, providing more precise location. The time required for the evaluation is greatly reduced by the development of a table lookup algorithm. Experimental measurement of magnetic fields on an open space agree well with the numerical evaluations in spite of the use of idealized assumptions. >