Two or three winding transformer cheaper
Two or three winding transformer cheaper
(OP)
I have a question for costs on power transformers. Would it be cheaper to get two 150MVA Two-winding transformer, or a single 300MVA Three-winding transformer?






RE: Two or three winding transformer cheaper
THAN TWO TRANSFORMERS OF 150MVA. BUT IS NOT WISE TO GO ON COST CONSIDERATION, AS THREE WINDING TRANSFORMER IS MORE
PRONE FOR SHORT CIRCUIT FAILURE.
RE: Two or three winding transformer cheaper
But yes, a single three winding transformer would be cheaper to manufacture & install as opposed to two-two winding transformers
RE: Two or three winding transformer cheaper
RE: Two or three winding transformer cheaper
RE: Two or three winding transformer cheaper
But you also have to consider resulting cost savings in primary protection, breakers, disconnects, relays, substation space requirements, etc.
RE: Two or three winding transformer cheaper
RE: Two or three winding transformer cheaper
RE: Two or three winding transformer cheaper
Voltages are not mentioned, but here’s a long shot: in some areas usual practice would be three [100MVA] single-phase transformers with a fourth identical spare. Overhead rigid bus and shoe-fly spans could allow the spare to be used without relocation, for any failed 1ø unit.
RE: Two or three winding transformer cheaper
Maybe this is a matter of local custom.
RE: Two or three winding transformer cheaper
Understood, dpc. It is indeed likely a "regional variation," but they are in service. I just wanted to cover all workable bases.
RE: Two or three winding transformer cheaper
A three winding transformer, for example, 15-kV primary, 480-Vsecondary and 4.16-kV tertiary, to substitute for two secondary load centers (480-V and 4.16-kV) having the same primary voltage source, has the following benefits:
One source breaker and feeder cable as opposed to two.
One transformer foundation as opposed to two.
Secondary switchgear breakers, bus duct, as well as MVA short-circuit duty can be materially reduced.
One spare transformer as opposed to two.
This configuration was used to appreciably lower the cost of many HPI plants.
RE: Two or three winding transformer cheaper
RE: Two or three winding transformer cheaper
Thanks
GusD