Can anyone please offer tips in modelling transformer zero sequence impedance of transformers in SKM Powertools. We mostly encounter three-phase delta-grounded wye units, some of which have neutral earthing impedances installed at the star point.
I have seen information stating none should be...
When performing fault current calculation study on a system with a motor controlled by a VSD, I am of the understanding that, for an overcurrent fault upstream of the VSD, fault contributions by this motor need not be considered as the VSD will not allow them to pass. Is this correct ?
With...
How does one calculate the required CT class such that the CT will not saturate at the maximum fault level with the new CT standard (AS60044.1-2003). There is no guidance, as was provided by App B of AS1675-1986.
From what I understand, AS60044.1 is similar to the corresponding IEC standard...
We have a client looking to replace his earthing transformers with new transformers. These transformers are to be connected to 3 parallel 11kV generators (one per generator), with resistors on the secondaries.
Our normal preference (w.r.t. power transformers) is for earthing resistors, as they...
