Measurement of Resistance of a Grounding Grid Model Using Magnetic Field Sensors

Precise measurement of resistance of a grounding grid is a fundamental factor in the protection of power systems. There are number of ground wires connected to the grid. ";Fall of potential"; method used for the measurement of a grid resistance gives incorrect measurement if part of the injected current shunted by ground wires is not considered. In this paper, resistance of a model of grounding grid system was measured using a method called "Single Point System" (SPS). SPS is based on the measurement of current using magnetic field sensors. Sensors used were Giant Magnetoresistive (GMR) sensors. SPS can measure grid resistance even with ground wires connected to the grid. Results obtained for a laboratory model gave error within 5% in the measurement of grounding grid resistance.