Avaliação do risco de choque elétrico em descidas de aterramento em redes de distribuição por meio da medição dos potenciais de toque e passo.

Abstract

Electrical grounding is indispensable in an electric power distribution system, aiming to guarantee the good performance and safety of the installation, so it must be reliable and have a level of quality compatible with the installation. In the overhead power distribution network, electrical grounding requires some care that must be observed in relation to the risk of electric shock. Because it is basically a naked conductor coming down the post that connects the neutral to the grounding rod, it can easily be accessed during an intervention in the installation and in the event of an energization also cause the electric shock. Therefore, the objective of this work is to try to understand in detail what happens when a ground is energized, what is the possibility of remaining in that condition, the voltage levels that can arise and the possibility of electric shock when approaching, through the measurement of step and touch voltages.It will also be opportune to compare the types of installations in different structures that may have better performance in controlling the risk of electric shock or even its elimination. The structures under test will be the wooden post, concrete with installation of the internal and external groundig to the post and the new system with self-grounded post. With the results, it was possible to identify the risk of electric shock in the descent of grounding, especially in the case of humid soil, when comparing the measured values with the values tolerable by the human body. It was also identified that the preventive methods adopted currently have flaws, and are not totally efficient in identifying the risk. This allowed to propose improvements in the security procedures and suggestion of new study proposals (sic).