125VDC Station Battery Fault Current
125VDC Station Battery Fault Current
(OP)
I'm in the process of designing a 125VDC battery for a power plant. This battery will be the DC supply for the 120VAC inverter as well as the switchgear, 2 emergency oil pumps, and other misc. users throughout the plant. I've sized the battery per the load profile I developed and determined that I will need at least 2 if not 3 (depending on the battery selected) strings of 60 cells to support the load profile. The problem that this presents is that as the number of strings increase the amount of fault current that is available goes through the roof, currently looking at 50kA +. I can't seem to find a panelboard or switchboard that is rated for this kind of fault current. Does anybody out there have any ideas how to handle this?
Erik
Erik






RE: 125VDC Station Battery Fault Current
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: 125VDC Station Battery Fault Current
RE: 125VDC Station Battery Fault Current
As Scotty says, if you can go 250 V, it is definitely worth considering.
RE: 125VDC Station Battery Fault Current
The data sheet for the DX battery is here.
http://
RE: 125VDC Station Battery Fault Current
RE: 125VDC Station Battery Fault Current
Factor in the resistance of the inter-cell links and the cabling to the switchgear. You won't have anything close to 25kA at the board. Not unless you're connecting it up with superconductors.
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: 125VDC Station Battery Fault Current
RE: 125VDC Station Battery Fault Current
Cables you can do yourself, you know how long they are!
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: 125VDC Station Battery Fault Current
RE: 125VDC Station Battery Fault Current
RE: 125VDC Station Battery Fault Current
Keith Cress
kcress - http://www.flaminsystems.com
RE: 125VDC Station Battery Fault Current
Thanks!
from my point of view, 50kA DC its crazy, what Scotty said.
RE: 125VDC Station Battery Fault Current
edienberg, you've forgotten to multiply by the 8 hours in the above so it should be 218*7.8*8 = 13020, which is getting closer to the mark.
Another 'rule of thumb' used is to multiply the 1 (one) minute rate by 10 to get an estimate of the short circuit value. The one minute rate for this battery is 3127 amps so a SCC of about 30 kA which is getting in the range of what Enersys has quoted to you.