transformer phase shift

[D!NNy]

Sorry very basic question:

For phase shift between the Delta and Wye connection transformer. when compared to the HV winding lets say between VAB shall be in phase with Vag on the LV side of the transformer.

However comparison is not among same quantities.

So HV ph to ground is used as comparison. VAG lags behind VAB by 30 deg.
If you put this in phasor rotation VAG leads Vag by 30 degrees.

My question if voltage phasor is measure Vab on LV side will it be in phase with VAB? or it will lag behind by 30 deg with comparison to VAB?

 

[Ingenieur]

Add
secondary V's
Van/+30
Vbn/+150
assume turns ratio = 1
observe polarity
sum is sec Vab

 

[Smart $]

...My question if voltage phasor is measure Vab on LV side will it be in phase with VAB? or it will lag behind by 30 deg with comparison to VAB?

Look at your transformer diagram...



First convention you must understand in these diagrams is that 0° is due west or to the left and angles increase (i.e. vectors lag) going clockwise.

V_ab (X1 from X2) is at -30°.
V_AB (H1 from H2) is at -60°.

Latter leads former by 30°.

 

[rian0201]

Basedfrom the figure above, you can always use the line to ground voltages, if H1 to neutral (fictitious neutral) is our reference, or 0 deg, and compare it to X1 to X0, you could say X1 to X0 leads by 30 deg since the rotation is clockwise.

Also, H1 or X1 doesnt need to be the starting point. It depends on where you set your reference.

I normally rotate the phasors to suit my preference.


Sent from Mars

 

[Smart $]

Basedfrom the figure above, you can always use the line to ground voltages, if H1 to neutral (fictitious neutral) is our reference, or 0 deg, and compare it to X1 to X0, you could say X1 to X0 leads by 30 deg since the rotation is clockwise.
...

Lags.

H1 from [PRI-N] is 0° reference.
X1 from X0 is 30°

Clockwise rotation is later in time, so lags by 30°.

 

[rian0201]

Yeah, my mistake...


Sent from Mars