Transformer Impedance and voltage drop
Transformer Impedance and voltage drop
(OP)
I am trying to calculate voltage drop on my transformer...
Primary voltage 16000V ,Secondary voltage 120/240
TX= 100 KVA %z=3.3 1phase
Can anyone help me how to calculate voltage drop on transformer.
The result of my calculation is given me 3.28% voltage drop, However my Supervisor has Voltage drop on Xfmr at 5.26%
Primary voltage 16000V ,Secondary voltage 120/240
TX= 100 KVA %z=3.3 1phase
Can anyone help me how to calculate voltage drop on transformer.
The result of my calculation is given me 3.28% voltage drop, However my Supervisor has Voltage drop on Xfmr at 5.26%






RE: Transformer Impedance and voltage drop
xnuke
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RE: Transformer Impedance and voltage drop
I don't know how he got 5.26%
RE: Transformer Impedance and voltage drop
It looks like he is either adding cable impedance - or he is calculating voltage drop for a much higher load. There is something said about 230 kVA just above the 5.26%
Are you interpreting the task correctly? Or is it your supervisor that hasn't?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Transformer Impedance and voltage drop
RE: Transformer Impedance and voltage drop
The transformer impedance is comprised of the transformer internal resistance and the transformer inductive reactance.
For voltage drop, use the transformer % regulation at the appropriate power factor. It will be less than the % impedance.
For loads of high power factor the transformer internal resistance predominates.
You must know either the transformer % regulation or the X/R ratio to calculate the voltage drop under normal loads.
The % impedance is only valid for short circuit calculations where the transformer impedance is the only impedance in the circuit.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Transformer Impedance and voltage drop
So base on this information :
Primary voltage 16000V ,Secondary voltage 120/240
TX= 100 KVA %z=3.3 x/R=3.1
Do you guys get 3.28% voltage drop as well?
This is only voltage drop on Transformer...
Thank you
RE: Transformer Impedance and voltage drop
That's 230.52% of full load current. Is this for calculating voltage dip during motor starting?
If you convert your supervisors figure to 100% loading it comes out as 2.28% voltage drop under full load.
That is probably correct at some power factor.
The voltage drop calculated by % impedance times rated voltage is a directed value. It is predominantly inductive. It can not be subtracted numerically from the rated voltage. It must be considered as a vector.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Transformer Impedance and voltage drop
RE: Transformer Impedance and voltage drop
There are loads attached to Transformer , But I don't know Which Kva he used! 100kva or 230KVa.
I am getting only 3.6% on transformer . I believe I am using either wrong voltage or Kva..
RE: Transformer Impedance and voltage drop
He has from
TX-------------------Point A Cable-----------------------point B cable.
5.26% --------- 1.26%dropA + 5.26------------- 2% drop on cableB + 5.26
Voltage drop--------=6.52% Total drop on point A---------=7.26%