Transformer winding phase angle shift
Transformer winding phase angle shift
(OP)
What is the phase angle difference between a HV delta 3 wire to LV wye 4 wire power transformer. I know the LV is either leading or lagging the HV by 30' but which is it?. The vector drawing on the transformer (not able to show symbols here) is a delta triangle with H1 at bottom left, H2 at the top and H3 bottom right. The wye symbol is on it's side with X1 on the stem which points to the left (towards the middle of the delta triangle), X2 is at the left top of the Y, X0 in the center and X3 at the right top of the Y ( -< ). This is not an unusual transformer. I perform various tests on transformers and was asked that question. I asked 2 engineers and got two different answers.






RE: Transformer winding phase angle shift
The transformer can be built with a 30 deg phase shift in either direction, but for U.S. transformer built to ANSI, the low will always lag the high, unless specified otherwise.
Hope that helps.
RE: Transformer winding phase angle shift
If anyone knows better please correct me.
RE: Transformer winding phase angle shift
ANSI/IEEE standard C57.12.70 §8 lists assorted delta-primary/wye-secondary-configured phase displacements of 30°, 90°, 150°, 210°, 270°, or 330°. Related info in ANSI/IEEE C57.105.
http://www.cooperpower.com/Library/pdf/R201902.pdf
RE: Transformer winding phase angle shift
RE: Transformer winding phase angle shift
As 1x1x1x points out, reversing the phase rotation reverses the phase shift from lag to lead (30 degrees in either case - that is set by the winding connections)
RE: Transformer winding phase angle shift
You can establish the same through a simple test.
RE: Transformer winding phase angle shift
RE: Transformer winding phase angle shift
Your Pal, Bazoomba
RE: Transformer winding phase angle shift
1. Electrical Transmission and Distribution Reference Book by Central Station Engineers of the Westinghouse Electric Corporation, East Pittsburgh, Pennsylvania, 1964.
Section 13 Three-Phase Transformers on page 106.
To make sure that the connection is correct, present (for example):
C---H3 X3---c
B---H2 X2---b
A---H1 X1---a
Which is for "Eag lags EAG by 30degrees"
RE: Transformer winding phase angle shift
Is the phase shift different for delta-wye or wye-delta (like advanced or retarded).
Is the phase shift always advanced 30 degrees LV to MV and retarded 30 degrees MV to LV?
My application is a 480v generator emergency board stepped up to 12.47kv.......and then from the utility it will then go through another transformer 12.47 to 480 for the normal power distribution. So, it's important for the phase angle to end up the same at the normal power distribution as the generator emergency board.
RE: Transformer winding phase angle shift
The low voltage side will lag the high voltage side by 30 degrees.
RE: Transformer winding phase angle shift
FAQ238-1090
Regards
Ralph
RE: Transformer winding phase angle shift
RE: Transformer winding phase angle shift
RE: Transformer winding phase angle shift