Power frequency AC voltage withstand test is to apply a certain voltage to the tested product, and maintain a certain time, in order to consider the ability of the tested product insulation to withstand various voltages, so as to ensure the safe operation of equipment. The absorptance of insulation resistance and leakage current and dc withstand voltage test and dielectric loss Angle measurement test can find a lot of insulation defects, but because of the test voltage is lower than the working voltage of subjects to taste, often for some insulation defects cannot be found in time, in order to further exposure equipment defects, check the electrical equipment insulation level and make sure whether can be put into operation, It is necessary to conduct ac withstand voltage test.
It is the most effective and direct method to identify the insulation strength of electrical equipment, and it has decisive significance for judging whether electrical equipment can be put into operation. The voltage, waveform, frequency of ac voltage withstand test and the distribution of voltage in the insulation of the tested product are consistent with the actual operation, so ac voltage withstand test can effectively find the more dangerous concentration defects of electrical equipment.
The higher the test voltage, the higher the effectiveness of finding insulation defects, but the greater the possibility of being broken down. For well-insulated samples, AC voltage resistance will gradually weaken the insulation strength, forming the accumulation effect of inferior insulation inside. The breakdown voltage of insulation is not only related to the applied voltage, but also related to the duration of pressurization. The breakdown voltage decreases gradually with the increase of pressurization time. Therefore, it is necessary to correctly choose the test voltage standard and withstand voltage time and equipment - test transformer.
