Lancie,
You just happen to be a few steps ahead of me.
This is the way I see it:
If the current flowing from the turbine is greater than the water flow, then the extra current will automatically be taken up by the mains, as the current flow out of the turbine will only be equal to the water supplying it. If the water increases to be greater than the current flowing from the turbine, then THAT DIFFERENCE is the one that needs the load dump.
So we should only be working on the positive side of the equation. Any thing less than this is no load dump.
Energy is allowed to flow from the mains, but not back into the mains.
Please explain what the ABS block actually does, because the instruction set help is very vague.
Mtn_Bkng_Dave :
What you are saying is exactly right except that I am confined to working with what I have.
I have a radio TX at the head works, with relay output RX at the turbine measuring four different levels.
This is a bit coarse to be called analog, and it only cost NZD1100 (USD700).
I am using a radio because it is rainforest country.
Everything else I think would work in with what you say.