Sistema eletrônico embarcado para diagnóstico das condições de aterramento de subestações energizadas.

Abstract

An important factor in the quality of electric power system is the Grounding System. Most equipment uses a substation ground connection as a reference for all other operating voltages. In protection, the objective of a grounding grid is to provide an equipotential surface in soil that will ensure that when a current circulating through the ground either from a fault or a lightning strike will not show differences in potential between specific substation points. The substation grounding systems require a periodic evaluation not only due to aging of ground loops, corrosion problems, apart from wear due to the occurrence of power surges. As the conditions to turn off the power substation increase in difficulty to pass, so increases the need to seek viable measurements alternatives, giving preference to methods of measurement of energized substation. On this paper is presented the development of a diagnosis in ground grid substation energized, which aims through the mapping of the surface tension of the soil (inside and outside the ground grid) substation, identifying the location of possible faults (e.g. zones of high ohmic resistance, corrosion, discontinuity) in the grid. It was developed an embedded electronic system capable of measure and to process several surface voltages distributed throughout the grounding grid. The system is also able to enhance behavior of the potential the soil surface, both in steady state conditions or in the occurrence of a short circuit, by processing the measured data via computer routine that exteriorize these results by two-dimensional graphics (2D). This evaluation must be done with the substation in working, where the current imbalance (unbalance) of the transformer is done reference to the rise of the ground potential.