Insulation resistance testing is a non destructive test procedure.
Insulation resistance test of transformer pdf.
Megger insulation resistance test device.
It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs.
Adjust megger tester at 1000 v dc.
The test is performed with a power factor test kit and the connections are the same as for the megger test the insulation resistance test.
Voltage for transformer testing because ac voltage simulates the internal stress that the transformers face during operating conditions.
The test measures the insu lation resistance between the phases and or between phase and ground.
Bushing power factor and capacitance.
Insulation resistance testing purpose.
A rated line to line voltage for three phase ac machines line to ground voltage for single phase machines and rated direct voltage for dc machines or field windings.
Values based on ieee std 43 2013.
September 5 7 2018 1.
B kv is the rated machine terminal to terminal voltage.
Insulation resistance decreases in temperature or moisture.
Pf 5 0 for dry type distribution transformers chl insulation pf tip up for dry type insulation should be 1 0 note.
Time resistance testing method this method is fairly independent of temperature and often.
Ansi neta mts 2015 table 100 11 insulation resistance test values rotating machinery for one minute at 40 c.
Overall power factor and capacitance 2.
The transformer neutral bushing is to be disconnected from earth during the test.
Apply the test voltage and note the reading.
Excitation current test insulating fluid dielectric tests insulation pf test insulation resistance test ttr test.
With a little record keeping and common sense however you can get a good picture of the insulation condition from values that are only relative.
Steps of this test.
Value at 60 seconds after application of the test voltage is referred to as the insulation resistance of the transformer at the test temperature.
The following tests are routinely conducted in the field on the transformer.
The insulation resistance test is of value for future comparison and also for determining if the transformer is to be subjected to the applied voltage test the winding insulation resistance test is a dc high voltage test used to determine the dryness of winding insulation system the test measures the insulation resistance from individual windings to.
Turns ratio test 8.
This test can be repeated during the service life of the transformer and verified against the result obtained during manufacturing as a check to determine if the insulation is malfunctioning or decaying.
Measure insulation resistance between low voltage windings and the main body of the transformer.
Clean the terminals of the transformer.
