Substation Double Fence Grounding

[RSChinn]

Our substation has a security fence (encloses all substation equipment) and a separate perimeter fence (around the edge of the property line). Both fences are separately grounded with the security fence ground tied to the substation ground grid. I am using WinIGS to evaluate the touch and step potentials. Is it correct to include the perimeter fence in the computer model? This perimeter fence is installed in a concrete footing for its entire length and is about 20 feet away from the security fence.

 

[jghrist]

The perimeter fence ground definitely needs to be included in the model. Modeling the fence concrete foundations can be modeled, but if left out will result in conservative touch-voltages.