RE: Busbar Insulation Resistance Testing
RE: Busbar Insulation Resistance Testing
(OP)
This is a blast from the past....
I was browsing through the archives at thread238-67387: Busbar Insulation Resistance Testing and was wondering about the answer to the original question.
Where I work We have always used 20Gigs @ 5kV for testing 11 & 33kV CB bushings (also used by default for the insulated buswork). I haven't really seen the justification for this - it just always has been the standard (albeit with a bit of interpretation for test conditions).
What do people generally accept as an ok IR result when maintaining 11kV or 33kV switchgear? Does the answer change much when considering indoor vs outdoor breakers or even outdoor @ 66kV?
Just curious what general practice is for others.
I was browsing through the archives at thread238-67387: Busbar Insulation Resistance Testing and was wondering about the answer to the original question.
Where I work We have always used 20Gigs @ 5kV for testing 11 & 33kV CB bushings (also used by default for the insulated buswork). I haven't really seen the justification for this - it just always has been the standard (albeit with a bit of interpretation for test conditions).
What do people generally accept as an ok IR result when maintaining 11kV or 33kV switchgear? Does the answer change much when considering indoor vs outdoor breakers or even outdoor @ 66kV?
Just curious what general practice is for others.






RE: RE: Busbar Insulation Resistance Testing
RE: RE: Busbar Insulation Resistance Testing
Thanks for responding.
These are standards for maintenance testing switchgear and busbars? Not to sound completely green, but what do these specs recommend?
RE: RE: Busbar Insulation Resistance Testing
RE: RE: Busbar Insulation Resistance Testing
RE: RE: Busbar Insulation Resistance Testing
The OP was simply requesting info on recommend test values when performing 5kv Insulation Resistance tests on equipment rated 11kV and 33kV. In most cases a DC IR test is performed prior to other tests be it AC, DC, VLF, etc. In many cases it may be only test required. Are you suggesting the DC Insulation Resistance test not be performed prior to other tests or not at all?
RE: RE: Busbar Insulation Resistance Testing
You are right in in your reply that he was merely asking for help with the test numbers, but to only answer that would ignore the 800lb gorilla in the room. One could have suggested test numbers from some source but that would still not be the end of the story, for as you know, with the many variables involved in DC testing, especially air insulated apparatus subject to varying atmospheric conditions that could throw the measured values from one end of the scale to the other. The test is worthwhile a a rough check of things, like if a ground was left on the sytem, it is no measure of the integrity of the eqipment with any ind of certainty and repaeatability. If it's all you've got, then thats's that. But taking it one step further and suggesting that instead fo that test, or in addition to it, if you have an AC hipot avaialable, that's the better way to go. Of course you know all of this and are just playing the debate game for the benefit of readers, which is great, I am trying to make sure that alternate methods to DC are investigated and that people stop to think about the physics behind the tests they do and what is actually happening and what it tells them. As with any testing, one must first ask what are the desired test results meant to reveal and once known, what can/will they do with the data.It's amazing how many people perform tests without any regard to the worth of the data collected and the actions available to take using that data.
Say hi to the gang.
RE: RE: Busbar Insulation Resistance Testing