Digislent how to enter input data to 3-W transformer

[NikolE]

Hello everyone!

I am struggling a little bit with the input data for 3-W transformer when it comes to Digsilent my purpose is to study only symetrical short circuit. Have anyone some experience with that?


My input:
_______________________________________________
Sn MVA 5,2
Un1 (HV) kV 11
Un2 (MV) kV 1,657
Un3 (LV) kV 1,658
I A 272,9
I A 905,9
I A 905,4
Tap pos. (-)
Connection (-) D(-7,5°)yn11d0
Short cir. Resistance (1-2) % 1,00%
Short cir. Reactance (1-2) % 9,95%
Short cir. Resistance (1-3) % 1,00%
Short cir. Reactance (1-3) % 9,95%
Short cir. Resistance (2-3) % 2,50%
Short cir. Reactance (2-3) % 15,40%
inrush current xIn 5x
_________________________________________
So based on this I have calculated the Sn for each winding (HV - 5,2 MVA, LV - 2,6 MVA, MV - 2,6 MVA)

My question is how to enter the positive sequence impedance (if via calculated copper losses + calculated usc% or with the uk% and re(uk))
and the second how to input this phase shift (-7,5°) - I got an an constant error to this.

Thank you very much in advance for any help! I really don´t know what to do :/

 

[7anoter4]

I don't know what Digislent program requires. However in my opinion
if you have the copper losses you can calculate the resistance and from
short-circuit voltage at rated current uk% you can calculate the impedance
and the extract from here the reactance
uk%=√3xZkxIn/VL_Lx100
r=Ploss/3/In^2
Xk=√(Zk^2-r^2)
First you have to calculate the impedance of each winding:
Z1=(Z12+Z13-Z23)/2
Z2=(Z12+Z23-Z13)/2
Z3=(Z13+Z23-Z12)/2
Usually the p.u. of the impedance is referring to the rated impedance Zn=VL-L^2/S
If the transformer symbol is according to IEC 60076-1 the connection is as following:

 

[7anoter4]

It is not possible to upload any image.I am sorry

 

[7anoter4]

 

[7anoter4]

There is a natural phase shifting[0 to-7.5o] considering the voltage drop through the transformer from I=0 to I=1.13xIn

 

[7anoter4]

Sorry. At D-do connection the phase shifting depends on power factor and current level. At D-yn11 connection , initially is 30o and from here the shifting depends on current module and argument.