Question

What Is Earth Resistance ?

Answer 1

Hint:An object's electrical resistance is a measure of its resistance to the movement of electric current. Resistance and conductance are not solely determined by the nature of a material; they are often influenced by the size and shape of an entity, as these properties are extensive rather than intensive.

Complete answer:
The resistance provided by the earth's electrode to the flow of current into the ground is known as earth resistance. The earth resistance is described mathematically as:
\[{\text{Earth}}\,{\text{resistance}}\,\,{\text{ = }}\,\,\dfrac{{\left( {{\text{Potential}}\,{\text{of}}\,{\text{the}}\,{\text{earth}}\,{\text{electrode}}} \right)}}{{\left( {{\text{Current}}} \right)}}\]
${\text{Earth}}\,{\text{resistance}}\,\,{\text{ = }}\,\,\dfrac{{\left( {\text{V}} \right)}}{{\left( {\text{I}} \right)}}$
Where,$V$ is a voltage spike that is measured in voltage and $I$ denote the current injected during the earth resistance.

The earth resistance rises with depth and is temperature dependent. While the temperature is above ${0^{\text{o}}}\,{\text{C}}$, the effect on ground resistivity is negligible; however, when the temperature drops below ${0^{\text{o}}}\,{\text{C}}$, the water in the soil freezes, increasing the resistivity. The structure of certain soluble salts has an effect on the earth's resistivity.

The earth's resistance varies from layer to layer. More moisture and lower resistivity are found in the lower layer of soil. If there is rough and rocky soil in the lower layer, the resistivity increases with depth. The resistance area or potential area of the ground is the area around the earth where the electrode is powered. The fault current pumped from the earth electrode travels in all directions away from the electrode.

Note:The resistance between the electrode and the point of zero potential is referred to as earth resistance. The potential fall method is used to determine the resistance between the earthing plate and the ground.