Investigating grounding grid integrity based on the current injection method

The purpose of this research is to develop a test method that is capable of determining the integrity of the grounding grid and clearly indentifying weak points or discontinuities. The concept of the proposed method is to inject the square wave current with high frequency (~500Hz) and high current (~10A maximum) into the grid. The magnetic field produced by the current flowing in the buried conductors can be measured above the grid conductor. A strong signal is indicative of no fault; no signal or very weak signal means the grid wire is damaged. The proposed method is verified using a scaled model of a grounding grid. Also, a current injection generator is built up to provide the required square wave current for the injection. The experiment in the lab showed that the proposed method works well on testing grounding grid integrity.