What Is a DC High Voltage Generator?

The essence of DC high-voltage generator

Simply put, it is a device that can convert 220V mains power into tens or even hundreds of kilovolts of DC high voltage. The core technology is high-frequency pulse width modulation (PWM), which maintains high stability of the output voltage through closed-loop regulation. The voltage stability of the HZZGF series can achieve fluctuations of no more than 0.5%, and the ripple coefficient is also less than 0.5%. These two indicators directly determine the reliability of the test data.

In which occasions is it mainly used

The preventive testing of the power system is the main purpose, which includes:

DC withstand voltage test for power cables: Apply a specified multiple of DC high voltage to the cable to verify its insulation strength

Leakage current test: measure the small current passing through the insulation layer under high voltage to determine the degree of insulation aging

Zinc oxide arrester (MOA) test: Measure the leakage current at a reference voltage of V1mA and 0.75 times V1mA

Insulation test for transformers, generators, and motors: to verify whether the insulation of large electrical equipment meets operational requirements

Voltage withstand testing of insulation materials and electrical components

Why is it DC instead of AC

For high-capacity capacitive test samples (such as long-distance power cables), if power frequency AC withstand voltage is used, the required test transformer capacity is extremely large, and the equipment is bulky and cannot enter the site. The DC high-voltage generator has a small volume and light weight - taking the HZZGF 80kV model as an example, the control box weighs 6kg and the high-voltage unit weighs 8kg, which can be transported by two people, making on-site operations very convenient.

Of course, DC withstand voltage also has its own limitations, and its equivalence to XLPE cable insulation is not as good as ultra-low frequency AC. National regulations have gradually restricted its use on new cables, but it is still an irreplaceable tool in lightning arrester testing, old cable testing, and insulation testing of various electrical equipment.