Jump to latest postHere is a question for you ,what is the winding resistance tolerance for a transformer test and what are you using as a reference for your answer.That was on the level four test.
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Junior Member
Posted January 18, 2015
Here is a question for you ,what is the winding resistance tolerance for a transformer test and what are you using as a reference for your answer.That was on the level four test.
IEEE 62 Guide for Diagnostic Field Testing of Electric Power Apparatus - Part 1: Oil Filled Power Transformers, Regulators, and ReactorsOriginally Posted by Larry5441
+/-5%
Junior Member
Posted January 20, 2015
You need to look at IEEE C57.12.90 it is a updated standard stating that winding resistance readings has no specific standards and will only be used as a reference .
Junior Member
Posted January 21, 2015
Adwell International LTD: If all readings are within one percent of each other then they are acceptable. Keep in mind that the purpose of the test is to test for gross differences between the windings and for opens in the connections.
Junior Member
Posted January 24, 2015
That was not the question ,it ask what was the tolerance differences not the goal of the test
Junior Member
Posted June 29, 2015
Pro Subscriber
So that's 5%, 1%, or "no standard" depending on the reference. The goal of the question may be for you to match the standard to the reference. I've also seen 1/2% for factory testing from Megger corp.
NETA Level III
Posted June 29, 2015
Pro Subscriber
According to Megger: The industry standard (factory) permits a maximum difference of 1/2 percent from the average of the three phase windings. Field readings may vary slightly more than this due to the many variables. If all readings are within one percent of each other, then they are acceptable.
For the source document, see this thread -> http://testguy.net/threads/1497-Tran...stance-balance
