winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
georgestolz said:So let's say I did not want my voltage imbalance to exceed 20V (110-130) under a sudden open service neutral. Being especially unkind to you in this exercise, I have a very unbalanced L-N inside the structure. Let's say, 50A on Phase A and 10A on Phase B.
What resistance would you have to engineer the GES to?
Assume a Utility resistance to ground of 20 ohms.
Now come on. That's easy. You want to keep the voltage imbalance to 20V, which means that the 'neutral' voltage cannot change by more than 10V.
You have a 40A current imbalance, so 40A must go down the neutral at no more than 10V. Total resistance of the return current must be less than 0.25 ohm.
You have a resistance to ground on the utility side of 20Ohm, so the grounding electrode system at the house needs a resistance of -19.75Ohm.
I believe that a retroencabulator can be configured to provide a suitable negative resistance.
-Jon