Earth surface potentials measuring device for large grounding systems testing

Abstract

Substation grounding system characteristics need to be examined periodically in order to check that protective functions have not been degraded over a longer period of time. The most important safety parameters are the values of touch and step voltages. However, the surface potential distribution contains additional information concerning grounding grid status and possible characteristics degradation trends. Inspection procedure needs to be well prepared prior to actual measurement during which the great deal of measuring information has to be acquired. General-purpose multimeters are inconvenient for the efficient conduction of measuring procedure and data management tasks. A novel application-specific measuring system for earth surface potentials measurement needed to be developed and realized. It consists of the smart measuring device accompanied with the integrated program environment on a personal computer for inspection planning and analysis.