Single phase sync check relay is a common practice (to save cost too) but with a caveat. Those systems are supposed to be correctly commissioned for phase rotation. Once correctly commissioned, most generators are not expected to reverse their direction unless you change the prime mover or the...
This is a common interconnect requirement for synchronous generators. (by most utility co. in the USA).
I interpret the utility's statement as them requiring reverse power relay. When the gen is capable of producing more power than the load on the feeder, it will back feed the utility, which is...
P=V*I*1.73 is for a "balanced" 3 phase power system, that is when I is equal in all three lines and V= V line to line.
For unbalanced system, calculate per phase values and add them up.
For each phase power, the formula is V*I where V is line to neutral or (Vll/1.732).
Rafiq Bulsara...
Yes, determining the safe fault current for a fuse is one of many important factors. Load current itself does not determine if the setup would be safe.
Start here to see just the list of considerations, never mind the how to manufacture and test those...
TheSwener:
Fuse manufacturing is not a DIY item.
You came here for an advice and you got it from some very knowledgeable and among the wisest members on this forum. Heed their advice. If you knew anything about the hazard involved in what you are asking, you would not have asked the question...
No. In your scenario you will be partly off loading the generator to utility, upon its return. I am not sure why you think what you think.
Rafiq Bulsara
http://www.srengineersct.com
Note that soft loading/unloading is always between two different sources, such as generators and utility or another gen power bus. Load is supposed to be up and running on one of the sources, before it gets transferred to the other.
Rafiq Bulsara
http://www.srengineersct.com
No. Unless your definition of soft loading is different than what is commonly understood. It may help if you state why do you think it could be a contradiction or a problem. Generators only see the loads on their terminals.
Rafiq Bulsara
http://www.srengineersct.com
What you describe ( if I understand it correctly) is a common setup. Transformer secondary parallleing is not a requirement for soft loading/unloading of the gen on the primary common bus.
Rafiq Bulsara
http://www.srengineersct.com
Also refer to NEC 110.14 (C)(1). One can argue, and even win at times, but I would use 60 dec C column ampacity for sizing conductors for 100A or less or sizes #1 AWG and smaller.
Rafiq Bulsara
http://www.srengineersct.com
