15kV Fuse

[jwparker]

Im trying to spec a 12.47kV load break switch with a 600A fuse, or close to it. Finding the 600A switch is easy but I cant seem to find a 600A fuse/fuse holder. Only 540A but requires 800A holder, what am I missing?

 

[jwparker]

Isnt ferroresonance not as big of an issue at 12kV

 

[racobb]

Not as prevalent as with the higher voltages but still can occur.

Alan

 

[rbulsara]

I have seen and resolved at least one case of ferroresonance at 13.8 kV.

Rafiq Bulsara

http://www.srengineersct.com

 

[jwparker]

well, given they are wye connected and at 12kV I suspect little issues with 1ph protection. Worse case we will install a vcb later.

 

[jwparker]

Still havent entirely resolved this issue. Even with double barrel fuses I cannot seem to get a 600A fuse within a 600A switch. I've checked schnider ele and square D with no luck..

 

[alehman]

S&C SM-5S:

http://sandc.com/products/smsml_id/smsml_ratings.asp

S&C Fault-Fiter:

http://sandc.com/products/faultfiter/faultfiter_ratings.asp

Alan
----
"It’s always fun to do the impossible." - Walt Disney

 

[Elmir]

Cutler Hammer RBA-800 series are offered in 450, 540 and 720A.

The 540A rating is really 600A (two fuses in parallel) derated by ten percent.

 

[jwparker]

Right, but isnt the RBA-800 an 800Amp fuse holder? Does that not require a 1200A switch?

 

[alehman]

You'll probably have to ask your Eaton rep. I can't tell from the literature. It may depend on your NRTL listing requirements.

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[Elmir]

The bus in your switchgear can be manufactured or modified as necessary to accomadate the RBA-800 fuse mounts.

The price of the fuses gets rather expensive. I have seen eurpean DIN size fuses used frequently due to lower costs. Using a vacuum breaker with protection relay may not be that much more cost wise compared with a set of RBA-800's, mounting parts and a set of spare fuse links.

Like alehman said, consult with the eaton rep and local regulations and codes first.

 

[jghrist]

You might try this Elastimold vacuum interrupter to replace both the switch and the fuse. I think the price will be about $15K.

http://tnbsun4.tnb.com:8080/ucon-img/utility_pages/general/prod_show4.htm

 

[jwparker]

yeah, Im going to get a quote for a sf6 switch vs. fuses. I need to find the number for an actual technical sales rep for some suppliers. I can only seem to find local low voltage reps and online (useless) run-around numbers.