modeling grounding system in FEKO
Dear friends,
I would like to know how I could use the IMAGE METHOD in the situation described below.
I'm simulating a grounding system. It is a 10m long horizontal grounding electrode buried at a depth of 0.5m in the ground. The studied soil has a conductivity of 0.001 S. The quantity I am evaluating is the electrode input impedance (Z).
For the grounding simulation, we observed that FEKO requires that the voltage source (that excites the system) has a connection with a PEC plane. In this way, the current can return/circulate through the system as the ground conducts current. The problem is that it would not be physically consistent to define the ground surface as a PEC plane because, in practice (in grounding systems), the potential at the ground surface is not constant and has a dielectric characteristic (just like the ground).
To get around this problem, I'm currently defining an air layer 5m above the ground surface and above that a PEC plane. A cable connects the upper PEC plane to the ground electrode. We position the voltage source at the cable connection point with the PEC plane (ie at the top of the cable).
This artifice of using an air layer provides good results, however, a new problem arises: the capacitive coupling between the horizontal electrode and the upper PEC plane. For this reason, I imagine that the most adequate way would be to use the method of images, with the ground surface being the plane of symmetry. However, I have no idea how to implement this in FEKO. I've tried several things but without success.
I would be very grateful if someone could help.
Answers
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How would you physically measure the input impedance? How/where would the signal generator be connected?
Feko supports connections of voltage sources onto lossy media.
In the below (attached), a very rough setup of two bronze plates with wire in between excited with a voltage source inside of an infinite 2D plane of "lossy earth" dielectric.
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