Paralleling of Dyn11 transfromer with Dz0 Transformer
Paralleling of Dyn11 transfromer with Dz0 Transformer
(OP)
Good day to you
LV switch board with 2 incomers + Buscoupler(with sync facility) is currently fed by one 2.5 MVA 6.6kV/415V, Dyn11 transformer and Proposed to add one more transformer from second source of 11kV. Engineering Contractor proposes a Transformer of 2.5MVA 11kV/415V Dzn0 vector connection. Request your opinion on what will be phase angle in the secondary side of both Transformer and will it be possible to parralel both transformers?
your valuable inputis appreciated
Ramesh
LV switch board with 2 incomers + Buscoupler(with sync facility) is currently fed by one 2.5 MVA 6.6kV/415V, Dyn11 transformer and Proposed to add one more transformer from second source of 11kV. Engineering Contractor proposes a Transformer of 2.5MVA 11kV/415V Dzn0 vector connection. Request your opinion on what will be phase angle in the secondary side of both Transformer and will it be possible to parralel both transformers?
your valuable inputis appreciated
Ramesh






RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
Is there a phase difference between the 11kV system and the 6.6 kV system that you haven't told us about?
Is one of these systems fed from an islanded generator?
Parallel operation as it pertains to vector groups assumes that both the primaries and secondaries are connected in parallel.
You are connecting systems in parallel, not the same as transformers in parallel.
There may be a vector shift between the systems due to multiple transformation steps on the way to 11kV and 6.6kV respectively.
The contractor may know something that we don't, do some more checking. You do want an answer before you proceed with this installation. It may be OK or you may need a different transformer.
Bill
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"Why not the best?"
Jimmy Carter
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
As jghrist says, there will be definitely be a phase shift between those two transformers, but this could be compensating for existing phase difference between the two primary sources.
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
Both the sources are from the same national 132kV Grid, I will check the upstream transformer schemes of 6.6 and 11kV sources.
Thanks again for the quick responses
Regards
Ramesh
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
David Castor
www.cvoes.com
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
If you assume the 11 kV and 6.6 kV sources are in phase, you are correct. But we do not yet know that.
David Castor
www.cvoes.com
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
Thanks again
Regards
Ramesh
RE: Paralleling of Dyn11 transfromer with Dz0 Transformer
David Castor
www.cvoes.com