On Thu, 01 Nov 2012 23:25:32 GMT, DerbyBorn
wrote:

I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

Large rotating machinery has a speed limit anyway. There's a capacity
limit to the amount of water/load and the hydro generator should be
matched closely to the water allowed to flow through it - in any case,
the upper sluices and the turbine inlets are sized to only allow this,
with some fine variation as the bloke said.
If you want extra power, you add more units or build bigger ones in
the first place.