Transformer turn ratio
- Thread starter panthripu
- Start date
- Status
Mostly that a Yd0 configuration is impossible. The 0 would mean that the LV reference phasor (V_ab) is in phase with the HV reference phasor (V_AN). The only configurations possible with a "0" are Yy0, Dd0, or Dz0.
Perhaps this webpage will help: http://www.transformerworld.co.uk/vector.htm
Last edited:
Voltage ratio is the same when considering a 3? transformer as a unit.
However, if considering the respective windings only, or a bank of 3 1? units, the voltage ratio would be V_in:V_out for Dd0 versus (V_in:V_out)/1.732 for the Yd1 configuration.
For example, if we have a 480V to 480V 3? isolation transformer, we can plainly see the voltage ratio is 1:1. If we now discuss the winding ratio, a Dd0's would be again 1:1, but a Yd1's would be 277:480 or 1:1.732.
voltage ratio transformer
voltage ratio transformer
I have the following measurement ratio of a transformer with Yd1 configuration with primary voltage 34500 V
Tap Sec.Volts Ratio Vp/Vs
1 240.0 124.488 143.75
2 267.4 111.732 129
3 301.8 98.996 114
4 321.3 92.988 107
The measured ratio with instrument shows the values below "Ratio" whereas therotical values should be "Vp/Vs".
voltage ratio transformer
I have the following measurement ratio of a transformer with Yd1 configuration with primary voltage 34500 V
Tap Sec.Volts Ratio Vp/Vs
1 240.0 124.488 143.75
2 267.4 111.732 129
3 301.8 98.996 114
4 321.3 92.988 107
The measured ratio with instrument shows the values below "Ratio" whereas therotical values should be "Vp/Vs".
Don't know why you are getting those measurements. Can you provide more detail on the method and means of measurement?
Oddly enough, the ratio of each tap's "Ratio" to "Vp/Vs" is approximately 0.866:1, for which 0.866 is equal to (√3)/2.
Transformer turn ratio
Well ,it really not an instrument dependent as it has been check with different measuring instrument.The methods uses injecting a known voltage on primary side and measures the secondry voltage.
I dont have exact calculation, but as the both side windings are of different configuration ,the factor root 3 is understandable. Does 30deg phase shift makes this difference?
Well ,it really not an instrument dependent as it has been check with different measuring instrument.The methods uses injecting a known voltage on primary side and measures the secondry voltage.
I dont have exact calculation, but as the both side windings are of different configuration ,the factor root 3 is understandable. Does 30deg phase shift makes this difference?
It could. Given a 30? vector and its polar coordinates as (ia,jb) and its magnitude as h, the ratios of the polar coordinate ia value to the vector magnitude are ia/h=cos30?=0.866.
Still lacking the information necessary to determine why the readings seem off. What equipment is being used, and how is it connected. Have you tried using a "third party" meter(s) to measure secondary voltages during the injection testing? I would do this to determine if it is the measurement method producing aberrant results or the transformer itself. It is likely one or the other is the cause, but not both... and I'm leaning to the measurement side :roll:
Last edited:
Well that would be the problem. The primary-winding-to-secondary-winding voltage ratio should be, for a Yd1:
(Vp/Vs)/(root 3):1, or (Vp/Vs)
root 3)
...but only if Vp is the primary Line-to-Line voltage. If Vp is the primary Line-to-Neutral voltage, the ratio would simply be:root 3)Vp:Vs
- Status