VLF Withstand Tester for Cable Protection Function Over-Current Protection

Principle of the ultra-low frequency insulation voltage test

The ultra-low frequency insulation withstand voltage test is in fact an alternative to the industrial frequency withstand voltage test. As we know, in the test of large generators, cables and other test products for industrial frequency withstand voltage test, because their insulation layer presents a large electrical capacity, so need a large capacity test transformer or resonant transformer. Such some huge equipment, not only bulky, costly, and very inconvenient to use. In order to solve this contradiction, the power sector has adopted a reduced test frequency, thus reducing the capacity of the test power supply. From the theoretical and practical proof of many years at home and abroad, with 0.1Hz ultra-low frequency withstand voltage test instead of frequency withstand voltage test, not only can have the same equivalence, and the volume of the equipment is greatly reduced, the weight is greatly reduced, theoretically the capacity of about one fifth of the frequency, and simple operation, compared with the frequency test superiority more. This is the reason why this method is commonly used in developed countries.
This product combines the advanced technology of modern digital frequency conversion and adopts microcomputer control, which makes boosting, bucking, measuring and protection completely automatic. Because it is fully electronic, it is small in size and light in weight. The large LCD display is clear and intuitive, and it can display the output waveform and print test reports.
This product has the following characteristics
1, rated voltage less than or equal to 50kV ultra-low frequency using a single structure (a booster); more than 50kV ultra-low frequency using a series structure (two boosters in series), so that the overall weight is greatly reduced, the carrying capacity is enhanced, and the two boosters can be used separately for low voltage level ultra-low frequency.
2,Current, voltage and waveform data are obtained directly from the high-voltage side sampling, so the data is accurate.
3,With over-voltage protection function, when the output exceeds the set voltage limit value, the instrument will stop and protect, the action time is less than 20ms.
4,With over-current protection function: designed for double protection of high and low voltage, the high voltage side can be stopped precisely according to the set value; the low voltage side will be stopped when the current exceeds the rated current, the action time is less than 20ms.
5,The high voltage output protection resistor is designed in the booster body, so there is no need to connect another protection resistor outside.
6,Because of the use of high and low voltage closed loop negative feedback control circuit, the output has no capacitive rise effect.