Hydro plant minimum flow unit induction or asynchronus unit selection

[apowerengr]

We are looking at retrofitting a new minimum flow unit of 400kW into an existing hydro plant - in this situation would you use an induction or asynchronus generator and why?

 

[davidbeach]

It depends.

What would be your source of excitation? Do you need to produce Volts or is it sufficient to just produce Watts? Probably lots more questions.

 

[apowerengr]

excitation from the grid connection - min flow unit will be connected to a local distribution feeder operated by the same utility which owns the hydro plant.

 

[waross]

The induction unit may be more suitable for flow variations. It will be easy to connect in that it will not require the close synchronization of a synchronous unit.
But I don't know first hand. I will be watching this thread with interest.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[cranky108]

Presently we are installing a 800kw Hydro unit. I wasen't a part of the selection, but it is an induction unit, with a capacitor bank installed closley.

This, however, reminds me of the first wind farm I saw. Each unit was an induction unit with an installed capacitor bank. But the problems are that the units would draw more vars with increasing power output.

My concerns are that during a fault, some distance away, there would be almost no reduction in voltage to the unit, so I might expect some fault contribution.
Question: How much, ball park, should I expect?

 

[edison123]

Induction machines score on cost, reliability (only the stator winding sees voltage and fewer parts to fail), ease of maintenance (almost nil except may be for periodic greasing) and relative safety on grid (since any short circuit across the machine terminals loses its excitation, if supplied by the grid).

Operation wise, I leave it to the experts to analyze which machine is better to operate and control. One drawback with induction machines is var requirement either from the grid or from the capacitor bank.

Muthu

http://www.edison.co.in