Grounding Microgrid Systems in Metropolitan and Commercial Areas

Adjacent-grounding systems, in metropolitan areas, are usually interfering, because moreover common external conductive parts interconnect naturally them. Their integration to constitute a grounding microgrid system GMS allows making each grounding system more extended than its ground electrode. It assists resolutely to present limited touch voltages permissible to persist longer than 10 s and so to create the conditions of an intrinsically safe grounding system ISGS. An intentional common integration of adjacent-grounding systems is admissible, because each one of the grounding systems must satisfy equal protection requirements prescribed by utilities. This paper deals with three sample cases of measurements on grounding systems in areas with high GSs density and of a large size. The tests allows identifying a grounding microgrid system assessing for each component ground electrode a dispersing capacity of the fault current more extended than its size up to the dimension of the efficiency saturation with the minimum impedance value. The identification by measures of grounding microgrid systems contribute to recognize and improve natural integrations and promote the progress of the common safety, regardless of formal validation.