Answering my own question, I would say no because if the bus bar current is broken down into vectors, one current component is perpendicular to the plane of the CT and has no effect.
Our utility 500 kVA xfmr operated at least at 660 kVA. We were told this was acceptable because the nightime and weekend load was very small. When we went to primary metering, the load dictated a 750 kVA xfmr (customer-owned) per NEC.
I seem to recall an NEC rule that prohibits operating...
Regarding PWR's post, the xfmr secondary voltage in this case is 12.47 kV and feeds the plant main standby bus--so no single-phase loads--but thanks anyway for discussing the broader principle.
The consultant design did include equipment grounding conductors to carry the earth faults.
When a generator with a wye winding is connected to a wye-wye xfmr, is a cable connection required between the two winding neutral points in generator and xfmr primary? (Such an existing installed system here has four full-sized neutral cables, but the consultant design drawings show none.)
I remember an EC&M article back in the '80's about problems with AC control relays having long wire connections. The article included tables based on wire size, and probably voltage, and provided recommended maximum wire lengths for use with AC relays to avoid disruptive levels of capacitive...
An earlier thread stated that protective relaying can be difficult using wye-wye xfmrs. But I don't see any protection problems using a 480 V primary (outdoor xfmr) fed from a standby generator having a molded-case breaker and zero-sequence sensor. The sensor would sense ground faults...
When a 480 V standby generator is used to feed a 12.47 kV service entrance bus through a step-up xfmr, it seems difficult to attain the IEEE Red Book Ansi Range A 117 V on a 120 V base. With an approx. 5% voltage drop in the xfmr, the generator output (120 V on 120 V base) minus 5% (not...
I've noticed that design consultants may ignore the ASD input current ratings when summing loads for ampacity calcs, voltage drop, etc. Instead, they only include the motor FLA values as though the motor was actually connected across-the-line and not ASD-driven where the ASD is wasting...
