PDA

View Full Version : winding resistance tolerance for a transformer test


Larry5441
January 18, 2015, 07:50 PM
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.
sepulveda7000
January 20, 2015, 12:56 AM
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 Reactors

+/-5%
Larry5441
January 20, 2015, 08:52 PM
IEEE 62 Guide for Diagnostic Field Testing of Electric Power Apparatus - Part 1: Oil Filled Power Transformers, Regulators, and Reactors

+/-5%

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 .
ruel guanzon
January 21, 2015, 09:12 AM
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 .

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.
Larry5441
January 24, 2015, 01:34 PM
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.

That was not the question ,it ask what was the tolerance differences not the goal of the test
rgrabis
June 29, 2015, 04:24 PM
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.
SecondGen
June 29, 2015, 04:33 PM
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-Transformer-winding-resistance-balance