Insulation Resistance Test Procedure Of Current Transformer

Insulation resistance decreases in temperature or moisture.

Insulation resistance test procedure of current transformer.

The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. Before conducting a transformer winding resistance test it is important to observe all safety warnings and take proper precautions ensure that all equipment to be tested is properly grounded and treat all high voltage power equipment as energized until proven otherwise by using the proper lockout tagout procedures. Insulation resistance is the ratio of the applied voltage dc to the total leakage current. Adjust megger tester at 1000 v dc.

Go to content 3. Isolation required for the test. Megger insulation resistance test device. Insulation resistance test of transformer is divided into three parts.

Required equipment for testing. Leakage current should be as small as possible therby ir value should be as high as possible r v i. 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. Verify nameplate ratings are in accordance with the approved drawings and.

Use caution when testing. Steps of this test. Variac step up transformer 0 2kv primary current injection set. Use the megger test at a low voltage side.

Clean the terminals of the 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. It is also done at site to ensure healthiness of a transformer that is to check loose connections broken strands of conductor high contact resistance in tap changers high. It is carried out as a type test as well as routine test.

Transformer winding resistance measurement is carried out to calculate the i 2 r losses and to calculate winding temperature at the end of a temperature rise test. 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.