- #1
parsifal
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I'm not sure of the proper term here, but I'd guess it is either earth, ground or grounding resistance.
The task is to compute this grounding resistance for a sphere electrode (radius a) in a ground (conductivity sigma). The definition given for grounding resistance "between the surface of the electrode and a distant point in the ground" is the ratio of voltage between these two points (let say a and b) and current to the electrode, U_ab / I.
But I don't really know how I should use the definition in this computation. All I can come up with is this:
sigma = 1/rho => rho = 1/sigma
[tex]\Large R=\frac{\rho L}{A},L=dr,A=2 \pi r^2[/tex]
[tex]\Large dR = \frac {\rho dr} {2 \pi r^2}[/tex]
[tex]\Large R=\int_a^b dR[/tex]
But this gives the resistance of the whole sphere of ground, right?
So should I just compute using the first equation, where L=distance between a and b, A=pi*a^2 (cross section of an imaginary tube just big enough to swallow the electrode)? Doesn't make sense either.
The task is to compute this grounding resistance for a sphere electrode (radius a) in a ground (conductivity sigma). The definition given for grounding resistance "between the surface of the electrode and a distant point in the ground" is the ratio of voltage between these two points (let say a and b) and current to the electrode, U_ab / I.
But I don't really know how I should use the definition in this computation. All I can come up with is this:
sigma = 1/rho => rho = 1/sigma
[tex]\Large R=\frac{\rho L}{A},L=dr,A=2 \pi r^2[/tex]
[tex]\Large dR = \frac {\rho dr} {2 \pi r^2}[/tex]
[tex]\Large R=\int_a^b dR[/tex]
But this gives the resistance of the whole sphere of ground, right?
So should I just compute using the first equation, where L=distance between a and b, A=pi*a^2 (cross section of an imaginary tube just big enough to swallow the electrode)? Doesn't make sense either.
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