The ground grid integrity and continuity test are described in IEEE 80 – 2000 standard, and it is one of the most efficient test methods and techniques for measuring the electrical characteristics of grounding systems. It is also known as a high-current test method, whose purpose is to check the continuity of buried ground conductors and connectors, ground rods, and bonding connections by injecting a high-test current (up to 300 A).
Ground Grid Testers (GGT Series) consist of 2 models – GGT200 and GGT300. The main difference between these models is the maximum test current.
DV Power GGT200 and GGT300 devices, in combination with the GGT-M module, make an ideal test system for contact resistance measurement of the grounding systems within the substations and other electrical facilities. Wireless communication between the GGT device and the GGT-M module enables remote start/stop of the test and monitoring of measured results.
The ground grid integrity test is performed by injecting continuous DC current between the inspected grounding point and the reference grounding point (e.g. transformer grounding). Finally, the condition of the ground grid is determined based on the obtained information about the current flow direction and amplitude, voltage drop, and as well as inspection of the contact resistance values.
Furthermore, GGT200 and GGT300 devices can also be used as powerful high-precision micro-ohmmeters for contact resistance measurement of the non-inductive test objects (e.g. circuit breakers). Due to its Both Sides Grounded and Remote-Control functionalities, the instrument accurately measures even in the most demanding environments, providing additional safety to testing personnel.
With the above-stated capabilities, GGT is an ideal test system for inspection of the grounding systems, as well as for contact resistance measurement of medium- and high-voltage circuit breakers, disconnecting switches, high-current bus bar joints, cable splices, and different high-current links such as earthing/bonding connections.