It may well be a hundred ohms or so of N-E 'electrode' On its own you might just about keep the lights on in a bus stop, in a PEN fault. But the idea of the electrodes is not really to provide a solid return path for normal load currents, like some low voltage version of a single wire earth return supply. Rather it is just to keep neutral near terra-firma potential when all is well, and provide some back up if the is a failure of what would otherwise be the one and only earth connection at the substation.
The other advantage of a horizontal electrode is that there is not such a sharp step voltage gradient on the surface during faults, (voltage contours being more ecliptical than point like) Under a footpath that is moot, but I guess if the rule book says do this, they do it every time.
It may well be a hundred ohms or so of N-E 'electrode' On its own you might just about keep the lights on in a bus stop, in a PEN fault. But the idea of the electrodes is not really to provide a solid return path for normal load currents, like some low voltage version of a single wire earth return supply. Rather it is just to keep neutral near terra-firma potential when all is well, and provide some back up if the is a failure of what would otherwise be the one and only earth connection at the substation.
The other advantage of a horizontal electrode is that there is not such a sharp step voltage gradient on the surface during faults, (voltage contours being more ecliptical than point like) Under a footpath that is moot, but I guess if the rule book says do this, they do it every time.
