2013 International Symposium on Lightning Protection (XII SIPDA), Belo Horizonte, Brazil, October 7-11, 2013
THE INFLUENCE OF SEASONAL SOIL MOISTURE ON THE DESIGN OF
GROUNDING SYSTEMS
Vilson Luiz Coelho
FASATC – Faculty SATC - Criciúma - Brazil
[email protected]
Alexandre Piantini
University of São Paulo - IEE/USP
Institute of Energy and Environment. São Paulo, Brazil
[email protected]
Ruy A. C. Altafim
EESC/USP – University of São Paulo
São Carlos, Brazil
Hugo A. D. Almaguer, Rafael A. Coelho
FURB - Blumenau, Brazil
Mílvio R. de Lima
Power Engenharia Ltda. Florianópolis, Brazil
Wallace do C. Boaventura, José Osvaldo S. Paulino
UFMG - Federal University of Minas Gerais. Belo Horizonte, Brazil
Plínio Luiz Nosaki
RGE - Rio Grande Energia. Caxias do Sul, Brazil
This paper discusses the influence of the moisture content on the seasonal
behavior of soil resistivity and on the ground resistance of protection systems.
Laboratory tests show that this influence is very large on the resistivity of
several types of soil, although field researches indicate a wide variation in the
resistivity and moisture content only in the topmost layers of the soil. However,
this variation may significantly change the ground resistance values of systems
with small dimensions, thus compromising the performance of protection
systems of electrical installations. The strong correlation between the soil
moisture, and consequently the soil resistivity, and monthly rainfall values
allows extrapolating resistivity measurements for the most critical conditions
and thus improving the design of grounding systems.