Insulation Resistance Test Standard For Transformer

The transformer neutral bushing is to be disconnected from earth during the test.

Insulation resistance test standard for transformer.

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. Value at 60 seconds after application of the test voltage is referred to as the insulation resistance of the transformer at the test temperature. Value at 60 seconds after application of the test voltage is referred to as the insulation resistance of the transformer at the test temperature. Insulation resistance test of transformer is divided into three parts.

Values based on ieee std 43 2013. 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. Clean the terminals of the transformer. 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.

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. Steps of this test. Measure insulation resistance between low voltage windings and the main body of the transformer. Insulation resistance decreases in temperature or moisture.

Leakage current should be as small as possible therby ir value should be as high as possible r v i. The transformer neutral bushing is to be disconnected from earth during the test. The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. Isolation required for the test.

Use the megger test at a low voltage side. Apply the test voltage and note the reading. Ieee guide for short circuit testing of distribution and power transformers csa standard can csa c88 m90 csa standard for power transformers and reactors 6 routine design other remark oil quality tests x quality resistance measurement x quality winding insulation resistance x quality core clamp insulation resistance x quality ratio test x. B kv is the rated machine terminal to terminal voltage.

Apply the test voltage and note the reading.