DC power protection references 2

[Mstrvb19]

Our plant has a +/- 125VDC/250VDC split bus DC power system to ensure operability in the event of a loss of offsite power. The DC system has protective fuses on both the supply and return paths (+125/Nuetral and -125/Nuetral) as is typical. I am having trouble finding a good solid industry reference for us to point to that recommends or requires this practice. This seems odd to me, since this is such a common practice and seems so straight forward, that I cannot find any standards requiring it. I have searched NEC and what IEEE standards I could get my hands on. Any suggestions on standards or other industry guidance that covers this?

 

[busbar]

Might look over IEEE Standards 1375 and 946.

These generally deal with ungrounded systems, although it sounds like you may have a solidly-grounded-neutral system. NEC Article 240 or the IEEE Orange Book may be your best bet.

 

[BJC]

One of the best references for this is the old GE industrial power systems book. I'm not sure of it's exact title. The book is a loose leaf book and been out of publication for a long time. It has a good section on DC protection.
GE has a lot of notes on there website. It may be worth writing them to see if it's available. There are copies around in GE sales offices, maby they will copy them for you.

 

[Mstrvb19]

Thanks for the tip, busbar- 1375 had exactly what I was looking for!

Also thanks to BJC- Those old books tend to have a lot of technical detail, I'll see if I can get my hands on that one.

 

[busbar]

Aside — If circuit-breaker control is involved, there are lot of subtleties and sage wisdom in

http://www.pes-psrc.org/k/rlytrckt.zip

[zipped MSWord file]

 

[BJC]

MStrvb19
I can scan it and send you a copy of the DC section. I may be next week before I can get it done.

 

[Mstrvb19]

busbar-THANKS! Great paper!
BJC-Sounds great if its not too much trouble!

 

[BJC]

Mstrvb19

I have the GE artical as a pdf file.
It's titled "D-C syatem Short-Circuit Current Calculations" IT's from The GE Industrial Power Systems Data Book".
It's old, dated Dec 3, 1956
If you want it I need an email address to send it to. It's a 336 Kb file.

 

[Mstrvb19]

cjturner@firstenergycorp.com