Earthing Grid Resistance IEEE Std. 80 Calculator
This calculator produces the earthing/grounding grid resistance for a substation based on total buried length of conductors, area occupied by the ground grid and depth of the grid.
Equation for earthing grid resistance
The equation is based on the IEEE Guide for Safety in AC Substation Grounding (IEEE Std 80-2013), section 14.2, equation 57 and essentially combines the resistive properties of a metal plate, conductors and the depth at which it is buried.
\(R_s = \rho\left[ \frac{1}{L_T}+\frac{1}{\sqrt{20A}}\left(1+\frac{1}{1+h\sqrt{\frac{20}{A}}}\right)\right]\)
Where:
A is the area occupied by the ground grid in \(m^2\).
\(\rho\) is the soil resistivity in Ohm.m.
\(L_T\) is the total buried length of conductors in m.
h is the depth of the grid in m.
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