essential and nonessential loads
essential and nonessential loads
(OP)
in an AC distribution panel how should the loads be distributed on essential and non essential busbars?basically what are essential and nonessential loads in a substation?should the same loads be distributed on both busbars ?are there any sources on the web?
thanks.
thanks.






RE: essential and nonessential loads
RE: essential and nonessential loads
Typicall critical loads are as follow:
1- DC subsystem (Baterry charger, UPS)
2- Communication for protection & voice(SCADA, PLC, radio,etc)
3- Control circuit (lights, relays, microprocessor equipment, mimic panels, etc)
4- Monitoring and supervisoring equipment(printer,GPS, Fault & event recorder,computer & monitor, etc.)
5- Local annuciator and Alarm system.
6- External & Internal lighting.
7- Security system (Intrussion, CCVT, etc)
8- Fire alarm circuits
9- Maintenance receptacle.
10-Other vital equipment if require(HVAC, pump,Motor operate equipment, compressor,etc.)
RE: essential and nonessential loads
so what remains to be tranferred on the nonessential busbar?
the diesel generator does not have enough power to feed all
those loads during emergency.
RE: essential and nonessential loads
http://www.usda.gov/rus/electric/bulletins.htm
See Bulletin 1724E-300, Chapter 15, AC and DC Auxiliary Systems. Read it and if you still have questions, come back to us.
RE: essential and nonessential loads
RE: essential and nonessential loads
It is not the intention of the list presented above to suggest connecting all auxiliary loads to the critical bus. What I trying to suggest is a list of common equipment that I believe often is found connected to the essential bus.
I would like to take this opportunity to mention that the philosophy to connect load on the essential bus could be based on the importance of the substation to achieve degree of reliability, availability and maintainability expected.
Comparing the number of equipment connected to the essential load in a typical 69 kV distribution substation and a 500 kV transmission substation, there is substantial differences in number and type of load connected to the essential bus.
Also the power source could vary. For instance, redundancy battery-bank/charger dedicated battery/charger for the communication system, independent AC power sources, stand-by generator, etc.
Please see the list of critical load on listed on page 674 of the reference posted by Redtrumpet for rural substation up to 230 kV.
RE: essential and nonessential loads
http://www.nfpa.org
for codes and more info.