fuse disconnects

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coke03p

Member
Sorry guys I have to ask another question like this hopefully somebody can help me. I am in Iraq, I work for the Corps Of Engineers with the 249th Engineer Battalion, Prime Power. We are installing a 10MVA transformer, 11 KV to 3800 KV. We don't usually work with voltages like that and I am sure you all are not accustomed to it as well. However I need to know what size Fuse Disconnects I need to install in amps in order to properly protect this equipment. Any help in this matter would be extremely appreciated as well as how you came up with this figure would be great as well in case of future installations where we would need to do this.

thank you for all of your help

SGT Jason M Petaccio
249th EN BN (Prime Power)
Camp Anaconda, Iraq
 

molotov27

Member
Re: fuse disconnects

Iraq.....taking a wild guess, you should be installing a new Virginia Transformer unit. There are several things to consider when installing fuse disconnects, especially when connecting to the grid. You need to take into account coordination with upstream and downstream, available short circuit MVA's at connection point, capacity of the transformer, voltages, connection, etc...there is no such thing as saying for a 10MVA unit, use this fuse. I would suggest this forum

www.eng-tips.com

I am not a utility guy, so any utility guys out there, please lend a hand. If not, there are a lot of utility power guys in the eng-tips.com and they are great helping out.
 

charlie

Senior Member
Location
Indianapolis
Re: fuse disconnects

I would like to help but I am not an engineer. My background is in distribution and I wanted you to know that I am not ignoring your question.

On a side note, thank you for your service. I was in the Air Force but was never in a place like that. I really appreciate what you and others are doing to protect our country.
 

bob

Senior Member
Location
Alabama
Re: fuse disconnects

coke03p
We all thank you and pray for your safe return.
Now, 10 mva at 11 kv is 525 amps. Might the primary be 115 kv?
 

hurk27

Senior Member
Re: fuse disconnects

Bob I was looking at the 3800kv. That would be 3.8 million volts? Do they make a disconect that could enclose that high of voltage? Which would be only 1.5 amps

[ October 19, 2004, 12:30 AM: Message edited by: hurk27 ]
 

coke03p

Member
Re: fuse disconnects

I would like to thank everybody for the help they have given to me in this matter. I have a question for Bob though. How did you come up with these numbers. I am not doubting your numbers but I am always hungry for knowledge and would like to know the math behind your answer.

the primary voltage is 33kv supplied from the Iraqis, its coming to us at 11kv, and we are dropping it on the LSA to 3800v and from there its broken down into user voltages of 400 volts.

just some info for you guys maybe that will help.
thanks all
SGT P
 
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