Dear PSSE Experts
I need to model the following 3-Winding Transformer in PSSE: 125/62.5/62.5 MVA YNd5d5 220/22/22 kV % Impedance: HV / LV1 - LV2 = 13% - I will assume X = Z
My question, what will be: Winding 1-2 MVA base; Winding 2-3 MVA base; Winding 3-1 MVA base
Also, what should be: Actual X1-2(pu); Actual X2-3 (pu); Actual X3-1 (pu)
Thanks in advance.
Use Impedance I/O Code = 2, for impedance on winding MVA.
Enter X1-2 and X3-1 as 0.13 pu on 62.5 MVA base.
X-2-3 is not given. Assume something, e.g. 0.3 pu on 62.5 MVA base.
The data record looks like this:
In 100 MVA base the reactance for each leg of the transformer is -0.032, 0.24 and 0.24 pu.
The reactance from winding 1 to 2 is 0.24-0.032 = 0.208 pu on 100 MVA base. On transformer base the reactance is 0.208*62.5/100 = 0.13 pu.
In this example the bus base voltage is the same as the nominal voltages of the transformer.
Thank you dear from bottom of my heart. Can I clarify something with you concerning above answer. Why we assumed that the 13% impedance is given @ 62.5 MVA ? Is it due to the fact that when the short-circuit test is performed rating will be 62.5MVA in all cases?
Another question, what is the criteria according to which you assumed X2-3 equal to 0.3. It should be greater or less than X1-2 & X3-1 ? Thanks
Asked: 2024-08-18 05:05:44 -0500
Seen: 62 times
Last updated: Aug 19
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