Liquid filled substation transformer - established levels for Megger test results acceptance

MrJLH

Senior Member
Location
CO
Was looking for some guidelines on megger acceptance results from a Dobel test that was performed on a transformer today.

NETA MTS 100.5 states a minimum resistance of 5000 megohms, but my test result was 900 megohms

Thanks
 

topgone

Senior Member
What is the max voltage rating of the transformer windings? Is your equipment rated at 15 kV where 5G-ohms is the minimum IR?
 

ron

Senior Member
If you are testing per the NETA guidelines, you either need to go to the transformer manufacturer specific values (as stated in NETA MTS) or you are stuck with the NETA values. I am guessing you have made the tests per NETA for voltage amount and time applied, and other adjustments needed?
 
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