Grounding Microgrid Systems in Metropolitan and Commercial Areas

The IEC/EN standards introduce the global grounding system GGS that ensures no dangerous touch voltages to all the interconnected grounding systems and, in practice, creates an intrinsically safe grounding system ISGS when permits indefinitely touch voltages no higher than the conventional limit value. The interconnection of the grounding systems through the cable shields of the utilities distribution contributes to constitute a global grounding system so that the utilities have the responsibility in validating the existence of a GGS. A grounding system, out of a GGS, has to satisfy safety conditions in reference to parameters of the point of delivery communicated by utility. The grounding systems, in metropolitan and commercial areas, are usually interfering and common external conductive parts interconnect them in fact. In these areas, an intentional integration between adjacent grounding systems of users, satisfying equal protection requirements, assists resolutely to satisfy the safety conditions of an ISGS. The constitution of grounding microgrid systems GMSs contribute to recognize and perfect situations in fact and promote the common interest of safety, regardless of formal validation from the utilities.