Why doesn’t the inrush change when I change the impedance of the transformer?
Question: When modeling a transformer in PTW and going to the TCC curves for a transformer, why doesn’t the inrush change when I change the impedance of the transformer?
Answer: The XFMR inrush point on the TCC is a fixed value (12 pu by default). If the XFMR is referencing a library then the inrush point is coming from the library but it is a single value for a selected XFMR size. The default value of 12 is just a typical inrush as specified in the Buff Book (IEEE Standard 242-1986, p.161) but users are recommended to change this value accordingly. The inrush may vary based on the performance of a specific model/type, thus it is recommended to consult with the vendor for the typical inrush of the specific xfmr being modeled.
Answer: The XFMR inrush point on the TCC is a fixed value (12 pu by default). If the XFMR is referencing a library then the inrush point is coming from the library but it is a single value for a selected XFMR size. The default value of 12 is just a typical inrush as specified in the Buff Book (IEEE Standard 242-1986, p.161) but users are recommended to change this value accordingly. The inrush may vary based on the performance of a specific model/type, thus it is recommended to consult with the vendor for the typical inrush of the specific xfmr being modeled.