Bentonite in IEEE 80 calculations

[Power0020]

Soil replacement is a desperate option for difficult design situations where the native soil resisitivy is very high.

IEEE 80 shows equations for grid resistance with concrete-encased rods but it has no say about how to calculate the grid resistance with encased grid horizontal conductors with a certain thickness. How much bentonite is required around the conductors to achieve the required resistance?

Would it be more easier to modify the soil model instead? it will be cumbersome to do that with a manual calculations but I have not seen any computer programs modelling conductor encasement...


Any clue?

 

[slugz]

Hi Power0020,

This is a question of how you are disposed to invest and if is viable to you...

In some situations, only using some products it is posible to achieve the correct resistance of your system.
I don't know if this help you, but here is some links to a product that do that ( by the way, i am not vendor of this product hehe), they have a software free..

Software -> Link
Product -> Link

In some cases where your terrain are so big, this method is very expensive and not viable..
So yes, you will need change location of your plant or add some meters of a good soil (in some case this solve the problem).

Regards,