Breaker kVA rating 2

[vtb1]

How can I calculate kVA/MVA rating of medium votage metal clad breaker?
What does kVA rating for breaker mean?

 

[desertfox]

Hi vbhagat

What other information do you have?

kVA= 1000*Volts*Current

desertfox

 

[rbulsara]

It is usually the fault level rating related to the 3 phase symmetrical fault current amps at the rated voltage. For example, a 14.4 kV breaker rated for 14,000A symmetrical fault current will be rated at 350 MVA. [(Sqrt 3)*14 kA*14.4 kV].

The rated MVA (or amps) is provided by the manufacturer, which should be equal or greater than the calculated short circuit current rating obtained by a proper short circuit current analysis of the system.

Rafiq Bulsara

http://www.srengineersct.com

 

[dpc]

MVA-based SC ratings for circuit breakers is a deprecated method, at least in the US (ANSI C37). Older breakers were rated on an MVA-basis. The ratings are still seen and published, but are nominal values only. You must use the actual kA ratings for the circuit breakers.

 

[waross]

And kVA = V x A / 1000
A 100 Watt incandescent lamp is 0.1 KVA, not 100,000 KVA

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[racobb]

OH....tha old Divide by 1000 thing!

Alan

 

[cflatters]

With DPC on this one all the way

DO NOT USE MVA - ALWAYS USE kA

The energy dissipation / heat is a function of I2t