Autotransformer presentation
Autotransformer presentation
(OP)
YNad1 400/220 kV, 400MVA , Z%=12.5 autotransformer
how we can present this transformer in fault calculations program where auto transformer is not available in the program library.
how we can present this transformer in fault calculations program where auto transformer is not available in the program library.






RE: Autotransformer presentation
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Autotransformer presentation
RE: Autotransformer presentation
I don't think that anyone will seriously build it, but if you take three autotransformers and connect one end of the winding off each transformer to the centertap of the next transformer you will have a delta autotransformer bank. A little geometry shows the ratio as 1:(sqrt.28)/2, (1:2.646) rather than 1:2. I'll leave the phase shift for you to consider. In the event that you wanted to run one 550 volt rated legacy machine tool from a 208 volt supply it would probably work.
Respectfully
RE: Autotransformer presentation
Back to the OP, he needs to check his nameplate again. My guess is that he has a Yyd and the 'd' is probably less than 35kV while the two voltages listed are the 'Y' and the 'y'. No phase shift between the H and M (Y and y) windings.
RE: Autotransformer presentation
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Autotransformer presentation
Again , the connection is YNa0(d1), 400/220/11 kV, 400/400/60 MVA
RE: Autotransformer presentation
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Autotransformer presentation
RE: Autotransformer presentation
You can represent the autotransformer by a 3 windings YgYgD by calculation ZH, ZL and ZT from ZHL,ZHT and ZBT. In EMTP-RV (www.emtp.com) you can directly enter the nameplate imprdances.
Regards,
Bahram7
www.simtech-Intl.com
RE: Autotransformer presentation
I believe that a delta tertiary winding will also transfer energy from the unfaulted phases into a line to ground/neutral secondary fault.
respectfully