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Hi all, I was refreshing my symmetrical components theory and performed a calculation in Power factory (Digsilent) to compare against my calculations in Excel. I got all of the figures correct, however I am unable to calculate a zero sequence voltage component "through" a transformer. The...

Hi all For a Y-y transformer ungrounded neutral, what will be the secondary and the primary voltages if phase A in primary is open?

Hi all, In the IEC standards for transformer and motors the following formula is provided for calculating the resistance at temperature Θ2: R2/R1 = (Θ2 + 235) / (Θ1 + 235) 235 = copper In University I learned the following equation: R2/R1 = (1 + 𝛼(Θ2-Θ1) What is the difference?

Hi I am struggling to calculate the impedances in Example 1, IEC 60287-1-3:2002 Annex A. Anyone who knows how the reactances are calculated? Thanks!

Hi Referring to thread238-305712. Im trying to derive the permissable touch voltage curves in standard EN50522 without any success. Can someone please share how to derive these curves? An ExCeL worksheet will be appreciated:) Many Thanks

Hi In IEC 60076-8 it is stated that YNd and Yzn earthing transformers has the same functionality. I understand the broken delta solution (YNd), but I am struggling with understanding the Yzn solution. For instance, if you have a 11 kV delta connected system and introduce a 11/0.69 kV Yzn...