Series resonant AC hold voltage will replace DC hold voltage

Hertz Power has long been committed to the research and development, manufacture and sale of resonance and DC voltage test equipment. Judging by the sales situation of the two products in recent years, the sales volume ratio of these two products has not been found to be so large. On the contrary, the sales volume of frequency conversion series resonance and DC voltage test equipment is almost the same, and the growth and decline are the same. The proportions are also similar. Hertz Power believes that the full realization of the withstand voltage test is very important to ensure the safe operation of equipment and systems.

To ensure the safe and reliable operation of cables, relevant international standards have clearly prescribed different tests for cables. The main test items are: measuring insulation resistance, DC holding voltage and leakage current. The measurement of the insulation resistance is mainlycalibrate to verify that the cable insulation is aged, damp and exposes insulation defects during the withstand voltage test. The DC withstand voltage and leakage current tests are performed simultaneously, the aim is to detect defects in the insulation and even cause hidden dangers in the cable insulation. From 1978 to 1980, the German company Sechiswag had 41 failures in XLPE cables with a voltage level of 10 kV and 87 failures occurred. The XLPE cables with a voltage level of 3 kV ~ 24.5 kV in Sweden have been in operation for more than 9,000 kilometers and 107 failures have occurred. There have also been many cable accidents in China. Many cable failures are caused by frequent DC voltage tests. cause negative impact. Therefore, relevant departments at home and abroad widely recommend using AC holding voltage instead of traditional DC holding voltage.

From the 1980s to the mid-1990s hadvanced countries such as Canada, Germany and the United States have established corresponding AC voltage test standards and promoted their application. Since the late 1990s, Guangdong, Beijing, Shanghai, Zhejiang, Shandong and other places in my country have successively issued interim regulations for the AC test of XLPE cables. The national standard GB50150-2006 "Electrical Installation Engineering Electrical Equipment Handover Test Standard" recommends the frequency conversion series resonance resistance voltage method.

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