Beneath every substation, there is a ground grid that provides proper grounding of all apparatus in substations (e.g. transformers, circuit breakers, capacitor banks, steel tower structures, etc.). The ground grid is usually made of copper-based conductors arranged as a square mesh of varying size (e.g. from 1 m x 1 m to larger mesh sizes). Each crossing is joined by welds or clamps. The purpose of this grid is to improve the safety of both personnel and apparatus in the substation. Over time, this grid can deteriorate due to corrosion, ground movements, grid fatigue, high energy conductance (lightning), and construction damage. All this can cause various safety problems.
DV Power GGT and RMO-EH Series are ideal solutions for ground grid integrity/continuity testing. The tests are performed by injecting continuous DC current between the desired measurement point and reference point. Finally, the condition of the ground grid is determined based on the obtained information about the current path and voltage drop, as well as inspection of the measured resistance values.