Dimensionamento de uma malha de aterramento para edificações urbanas na cidade de Crateús

Abstract

The grounding system is a fundamental element for the safety of electrical installations, as it aims to protect people and equipment against electric shocks and overvoltages resulting from faults or electrical discharges. In this context, this study aims to perform the design of a grounding grid for a standard residential building located in the municipality of Crateús, in the state of Ceará, Brazil. In order to identify the nature of the local soil, measurements were carried out on three grounding systems of power transformers in the city, indicating a clayey and plastic soil. The soil resistivity range was considered between 1 Ω·m and 50 Ω·m, and based on these values, the grounding grid was designed. Subsequently, step and touch voltages, as well as the electrical resistance of the grounding system, were evaluated to ensure that the obtained values remain within the permissible limits for human safety, as established by technical standards. The results showed that a ring-shaped grounding grid surrounding the residence, buried at a depth of 0,6 m and using a bare copper conductor with a cross-sectional area of 50 mm², represents an effective solution to ensure a safe and efficient grounding system.