How is the integrated rating calculated for HVL switches with boric acid fuses? How is the MVA calculated for the switch only?

Issue:
Integrated rating calculation for HVL switches

Product Line:
Switchgear

Environment:
Installation/Setup

Resolution:

Integrated rating for HVL switches with boric acid fuses:

The integrated rating is limited by the switch to less than the full interrupting capability of the fuse.

Three Phase MVA = system nominal voltage, kV X symmetrical amperes, kA X 1.732

For example on the 38kV HVL switch - look for the lowest rating of the switch. In this case it is the fault close rating of 20kA Asym.

20kA Asym Amps = 12.5kA Sym Amps

The nominal voltage is 34.5kV for this example.

Therefore the Three Phase MVA is 34.5kV X 12.5kA X 1.732 =
747 MVA

Integrated ratings can be found in Tables in the Pricing Guides and Catalog Sections for the Product.


CTA-ID : 2011148

Released for: Schneider Electric USA