Implementação e avaliação de circuitos verticais para medição de resistência de aterramento em subestações

Abstract

The measurement of grounding grid resistance in electrical substations is a fundamental step to ensure the safety and efficiency of the power system. Traditionally, these measurements are conducted using auxiliary circuits positioned horizontally on the ground. However, in congested areas, especially in urban environments, this approach can become impractical due to the lack of available space. This study presents a new methodology for measuring the resistance of grounding grids in substations located in congested areas, using auxiliary measurement circuits arranged vertically in the ground. Important aspects were evaluated, such as the possibility of measurement with two auxiliary electrodes maintaining a 76% proportion, the appropriate depth of the electrodes, the influence of soil stratification in horizontal layers, and the presence of metallic objects near the measurement circuits. For this study, theoretical and experimental investigations were carried out, with reduced and full-scale models, to validate the feasibility of this approach. The results demonstrated the effectiveness of the proposed methodology, including the use of the Fall of Potential (FoP) Method with this measurement arrangement. The study shows that the 76% proportion is feasible for measuring grounding resistance in both uniform and stratified soils. For all scenarios evaluated, the results confirmed the feasibility of the proposed technique, highlighting its consistency and potential applicability in the measurement of electrical groundings.