During the operation of power equipment, the insulation will gradually deteriorate and form defects under the action of electric field, temperature and mechanical vibration for a long time. Various test methods have their own strengths, and they can all find some defects, reflecting the insulation condition. Except for the power frequency AC hipot test, the test voltage is often lower than the working voltage of the power equipment, as a guarantee for the safe operation of the equipment. It is not powerful enough.
The power frequency AC withstand voltage test conforms to the electrical conditions that the power equipment is subjected to during operation, and the AC withstand voltage test voltage is generally higher than the operating voltage. Therefore, the equipment that has passed the power frequency AC hipot test has a large safety margin. The purpose of the power frequency AC withstand voltage test is to assess the insulation strength of the power equipment and verify whether the equipment has the necessary conditions for reliable and safe operation in the power grid.
The significance of AC hipot test
The test voltage of AC hipot is generally much higher than the operating voltage of the equipment. Excessive test voltage will cause the insulating medium to heat up and discharge, which will accelerate the development of insulation defects, so it is a destructive test. Before the AC hipot tester, various non-destructive tests should be performed on the equipment under test, such as measuring insulation resistance, absorption ratio, dielectric loss factor, DC leakage current test, etc. After comprehensive analysis of the test results, the AC withstand voltage test can be carried out to prevent the defects from expanding during the AC withstand voltage test. The AC withstand voltage is an effective and direct method to identify the quality of equipment insulation an important means of operation.