METHOD FOR DETERMINING ELECTRICAL CHARACTERISTICS OF UNDERGROUND METAL STRUCTURES Russian patent published in 1998 - IPC

FIELD: electric measurement technology; grounding systems of electrical equipment at power stations, transformer substations, etc. SUBSTANCE: method involves application of ac current of 200 to 1000 Hz frequency to underground structure and measurement of strength of magnetic field built up by applied current at points above ground surface along structure route; current is applied by connecting current supply poles to two points of grounding circuit spaced apart through maximum possible distance within grounding circuit area; location of components of grounding circuit along its route and their ties with electrical equipment are found by shifting field strength meter in parallel to ground surface and their depth is determined by shifting field strength meter perpendicular to ground surface. EFFECT: facilitated location of components of complicated grounding circuit and their trouble- shooting.