Why power frequency AC withstand voltage test?

The power frequency AC withstand voltage test(AC hipot test) is to apply a certain voltage to the test object and maintain it for a certain period of time, in order to consider the insulation capacity of the test object to withstand various voltages and ensure the operation of the equipment. Although insulation resistance and absorption ratio tests, leakage current and DC withstand voltage tests, and dielectric loss angle measurement tests can detect many insulation defects, due to their test voltage being lower than the working voltage of the test object, some insulation defects cannot be detected in a timely manner. In order to further expose equipment defects, check the insulation level of electrical equipment and ensure that it can be put into operation, it is necessary to conduct AC withstand voltage tests.

It is an effective and direct method for identifying the insulation strength of electrical equipment, and it has decisive significance in determining whether electrical equipment can be put into operation. The voltage, waveform, frequency, and distribution of voltage inside the insulation of the tested object in the AC withstand voltage test are consistent with the actual operating conditions. Therefore, AC withstand voltage can effectively detect dangerous concentrated defects in electrical equipment.

The higher the test voltage, the more effective it is to discover insulation defects, but the greater the possibility of the tested object being broken down. For samples with good insulation, AC withstand voltage will gradually weaken the insulation strength, forming an accumulation effect of poor quality inside the insulation. The breakdown voltage of insulation is not only related to the applied voltage, but also to the duration of pressurization, and its breakdown voltage gradually decreases with the increase of pressurization time. Therefore, it is necessary to correctly select the standard of test voltage, withstand voltage time, and equipment - test transformer.

Weshine Electric Manufacturing Co., Ltd.