It is currently Sat Aug 08, 2020 5:12 pm



Post new topic Reply to topic
Author Message
ekstra   ara
 Post subject: Utility source impedance
PostPosted: Sat Oct 04, 2014 10:52 am 

Joined: Sat Oct 04, 2014 10:42 am
Posts: 3
The utility company has provided me with the actual fault current on the secondary side of the Utility transformer but no source impedance information. Would the source impedance be applicable on the secondary side of the utility transformer?


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Utility source impedance
PostPosted: Sat Oct 04, 2014 12:31 pm 
Plasma Level
User avatar

Joined: Wed May 07, 2008 5:00 pm
Posts: 822
Location: Rutland, VT
The source impedance on the secondary side of the transformer would include the transformer impedance.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Utility source impedance
PostPosted: Sat Oct 04, 2014 2:33 pm 
Sparks Level
User avatar

Joined: Wed Jun 10, 2009 5:00 pm
Posts: 263
Location: Toronto
jfann wrote:
The utility company has provided me with the actual fault current on the secondary side of the Utility transformer but no source impedance information. Would the source impedance be applicable on the secondary side of the utility transformer?


What is the transformer nameplate KVA rating, %Z and X/R ratio, and how big is the fault current value provided by the utility company on secondary of the transformer?


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Utility source impedance
PostPosted: Sun Oct 05, 2014 11:26 am 

Joined: Sat Oct 04, 2014 10:42 am
Posts: 3
2500 kVA at 5.7%Z (X/R unknown), 45kA fault current.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Utility source impedance
PostPosted: Sun Oct 05, 2014 12:44 pm 
Sparks Level
User avatar

Joined: Wed Jun 10, 2009 5:00 pm
Posts: 263
Location: Toronto
jfann wrote:
2500 kVA at 5.7%Z (X/R unknown), 45kA fault current.


What is the transformer secondary voltage?


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Utility source impedance
PostPosted: Sun Oct 05, 2014 5:27 pm 

Joined: Sat Oct 04, 2014 10:42 am
Posts: 3
480V. (Transformer is 24kV to 480V)


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Utility source impedance
PostPosted: Sun Oct 05, 2014 7:31 pm 
Sparks Level
User avatar

Joined: Wed Jun 10, 2009 5:00 pm
Posts: 263
Location: Toronto
jfann wrote:
480V. (Transformer is 24kV to 480V)


The source impedance, avail short circuit current and short circuit MVA on primary side of the 2500KVA, 5.7%Z 24KV/480V rated transformer with 45KA avail short circuit current on its secondary is roughly equal to 2Ohms, 6kA and 250MVA respectively.


Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 7 hours


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
© 2019 Arcflash Forum / Brainfiller, Inc. | P.O. Box 12024 | Scottsdale, AZ 85267 USA | 800-874-8883