high voltage transformers
high voltage transformers
(OP)
Can someone please help. I would like to know, why most HV transformers are connected Star-Delta, either on the primary or on the secondary. Does it have to do with the fault levels, or not. Why not just connect it Star-Star.






RE: high voltage transformers
A three legged, three phase transformer core will often over heat unless it has a delta winding to accomodate third harmonic magnetic flux, and unbalanced flux due to unbalanced loading.
Some transformers have a delta tertiary winding for this reason.
respectfully
RE: high voltage transformers
RE: high voltage transformers
RE: high voltage transformers
RE: high voltage transformers
RE: high voltage transformers
Some info on different transformer connections:
h
In addition to the previous posters:
Winding configuration: A lot depends on application and maybe in a lesser extent on previous history. Like David said, star-star transformers are still used. Another application for star-star trsfs are as station transformers in Power station auxiliary systems.
Star connections are usually preferred on the LV-side for grounding issues. To prevent zero-sequence currents flowing through the trsf, the HV-side is normally connected in delta (like stated by dpc)
On higher voltages windings (windings subjected to a voltage of 66kV and higher) are connected in star, because, in a star-connection, the winding isolation can be degraded towards the neutral point. (More Insulation = more money) In the case the secondary might be delta (preventing through-flow of zero sequence currents) or star, depending on the application.
Regards
Ralph
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