GSU Transformer for 10 MVA Hydropower Unit?

[kmh1]

Is a generator step up transformer typically specified for hydroelectric generators in the 10 MVA range or is a standard distribution transformer typically applied? I understand that GSU transformers have different specifications for power flow in the reverse direction for large generators but I am not sure if the units are even available in this power range.

 

[davidbeach]

In my world, at least, the biggest difference would be that the standard distribution transformer would be Dyn while the GSU would be Ynd. Not readily interchanged.

 

[Power0020]

the important aspect here is the %impedance limiting the system peak transfer capability.

 

[kmh1]

Thank you. My specific situation is a little different than a standard grid connected power generator in that the generator is a 4160 Volt unit embedded in an industrial distribution system where the system is being upgraded to 13.8 kV and a tie transformer is being considered between the generator bus and the new system. The existing 4160 volt system that the generator is connected to has a supply transformer with the low impedance grounded neutral. A 4160 wye - 13.8 kV delta transformer is being considered for the tie transformer since the 13.8 kV system already has other ground sources.

 

[cranky108]

Do you actually need a ground on the 4160? Or will a impedance grounded, or ungrounded source make it easer to work with?
I think those are the questions being implied.

There should be little difference between a GSU or any other transformer, unless you specify a condition of use that is not normal. The condition of use would be something like high harmonic, or alitutude, or cooling, or tempeture range.

 

[prc]

Some decades back I made a 10 MVA 3 phase 220 kV GSU for a gas turbine project. It is quite tricky transformer esp from impulse with stand point of view but not impossible. In your case HV is only 13.8 KV and hence it is quite an ordinary GSU or DT whichever way you want to consider.
Instead of tie transformer, why not connect the generator directly to 13.8 bus by a standard Yd GSU ?