Single phase test for switchgear 1

[dgavric]

I have a question about the single phase test according to ANSI 37.55- 5.9.1.2 chapiter. My test will be make for 50kA short current, 2 sec. and for 130kA peak current, 10 cycles (60Hz).I like to know how to do this test? What about the electrical connection and ground bus size.My ground bus is a cooper cable gauge 4.0 bolted to a cooper plate (2"x 1/4&quot. The cooper plate is bolted to switchgear floor.
What will be temperature rise of cooper and what is mechanical stress?

Thanks for your help.

 

[wbd]

What is the purpose of this test? I don't have that ANSI std handy but it sounds more like a factory test.
Are you trying verify integrity after installation? A ductor test of the bolted connections andt then a megger test of the assembly should accomplish that.

wbd

 

[dgavric]

Thanks wbd,
The purpose of this test is to check mecanical stress of the ground bus and switchgear assembly.It is a ANSI conformance test (type test) for metal-clad switchgear.A megger test of the assembly does not accomplish that. The current for this test must be rated short-time current for switchgear assembly,in my case it is 50kA.I don't know where I should be make short-circuits in the switchgear. Is there someone in the forum who already is done this type of test? Thanks,

 

[buzzp]

I have not done such a test. UL usual did these tests for us on overload relays. Granted they were not quite as high of currents but close. I guess they would use a step down transformer with large gauge wire to source that kind of current for short durations. The trick is to get one with large gauge wire so it does not evaporate when that kind of current goes through it. I don't even know where to look for such an animal, just taking a guess as to how they do it. Good luck. Oh by the way 'cooper' is spelled 'copper'.

 

[busbar]

Minor aside... One way to conduct short-interval high-current testing is with a massively braced motor-generator set with requisite flywheel.

http://www.bussmann.com/services/gubany/

Now that’s my idea of superior blood-and-guts entertainment.

I think Ferraz may have a roughly similar arrangement in Europe. [Italy?]

 

[pwrman]

Rent a Circuit Breaker tester you should be able to find one with that cap., Electrical Power Solutions Ltd.

http://www.e-p-solutions.com

 

[DanDel]

A C/B tester may put out 50kA, but only through a very low impedance (the closed contacts of a C/B). The buswork of a switchboard will have a higher impedance and will limit the current significantly. In any case, the fault current will not be backed by the rated voltage which is what the test requires. I believe this test can only be accomplished with LARGE equipment, and is typically done by switchgear manufacturers.