| ZnO varistor is an important overvoltage protection device in the field of electronics and information technology.It plays a vital role in the safety of the operation of electronic and communication systems.Based on the MOV aging test system,this paper carried out a study on the change characteristics of ZnO varistor temperature characteristics,charge rate characteristics and aging characteristics under long-term DC voltage under thermoelectric stress;conducted AC aging tests,and compared the impact aging tests with DC aging tests.The experiment and analysis result table proves:1)Electrical stress and temperature stress are important factors affecting the leakage current and power loss of zinc oxide varistor.2)In the long-term DC aging test,the test group with a higher charge rate ages faster than the test group with a lower charge rate;the test specimen with a higher test temperature ages much faster than the test specimen with a lower test temperature;The specimen with a larger sheet diameter ages faster than the specimen with a smaller sheet diameter.3)Comparison between AC aging test and DC aging test.Under the same test conditions,the AC aging speed is much slower than the DC aging speed;there is also a huge difference in the static electrical parameters of the test product.4)Comparison of impact aging test and DC aging test.Under the action of unipolar pulse and unipolar long-term field strength,there are similarities and differences in the damage of zinc oxide varistor;electrical parameters of the two groups of test samples also differ.Due to the large differences in the mechanisms and results of DC aging,AC aging,and impact aging mechanisms,traditionally reducing the varistor voltage value to 10%of the initial value as the end of life test for aging experiments requires further research for DC aging.The DC aging life criterion needs to be comprehensively judged from varistor voltage,non-linear coefficient,leakage current,leakage current,power loss and other aspects. |
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