Short-circuit calculation with IEC363
Short-circuit calculation with IEC363
(OP)
Hi all!
I am currently trying to calculate following IEC363 standard the short-circuit current on the secondary side of a distribution transfomer supplied by 3 6.6kV generators of different powers. Would any-one know if it possible to avoid using the "equivalent generator" method described in this standard? If yes, how could I proceed?
Thanks in advance...
I am currently trying to calculate following IEC363 standard the short-circuit current on the secondary side of a distribution transfomer supplied by 3 6.6kV generators of different powers. Would any-one know if it possible to avoid using the "equivalent generator" method described in this standard? If yes, how could I proceed?
Thanks in advance...






RE: Short-circuit calculation with IEC363
Would you please clarify in which page this method is described or please send a copy to me.
With Best Regards,
RE: Short-circuit calculation with IEC363
"If the effects of the primary circuit components cannot be neglected, then the impedance due
to the transformer must be added to the (equivalent) generator impedance, and new time
constants evaluated. These new parameters may then be used to determine the timedependent
short-circuit currents as outlined in 8.2."
Finally, after thinking for a long time about that and trying to carry out simple hand calculations to understand this, my conclusion is that it is necessary to use this complicated equivalent generator method.
Regards,
RE: Short-circuit calculation with IEC363
Could it mean equivalent impedances of the multiple generators (and any other impedance such as cable, or other contributing sources)? It would be a reduction of generator impedances in parallel, in sereis with the transformer impedance.(All impedances converted to a common base if using PU method)
By time dependent SCC do you mean SCC values during different phases? E.g: first 1/2 cycle substransitent (X")state , trasnient (X') state and steady state (X)??
If you are using a software, its should take care of everything automatically for you.
Sorry if I did not understand your question correctly.
RE: Short-circuit calculation with IEC363
IEEE Standards are using Zsys and Vsys for the power supply system input to the short circuit calculations.
If the load is relatively large with respect to the generator rating, the generator equivalent impedance should be considered to obtain accurate short circuit current results. The equivalent generator impedance is in series with the transformer impedance.
RE: Short-circuit calculation with IEC363
http://www.dcmt.bc.ca/PDF%20DOCS/SCC%20Rep%20R1.pdf
etc. for more info