VLF-120KP

VERY LOW FREQUENCY TESTER FOR HIGH VOLTAGE CABLES

Very low frequency tester for high voltage cables VLF-120KP is designed for testing high voltage cables and other objects which exhibit a significant isolation capacitance, with very low frequency voltage with an amplitude value of up to 120 kV or DC voltage of negative polarity of up to minus 120 kV.

VLF-120KP is a mobile unit and could be used as both a standalone apparatus or as part of cable test vans.

The method of testing the insulation of the high voltage cross-linked polyethylene (XLPE) cables using an AC very low frequency voltage is considered to be the safest and the most reliable compared with any other testing methods. It is widely believed that testing with DC voltage can damage a fully working cable due to accumulation of the space charge. Equally, using voltage of the mains frequency cannot be justified as the required power of the testing apparatus turns out to be too large to be used in practice.

Very low frequency tester VLF-120KP forms a testing voltage of the rectangular form with frequency 0.1 / 0.05 / 0.02 Hz. The change in polarity happens due to the free oscillation process, which is formed by VLF-120KP and lasts between 2 and 10 ms, depending on the capacitance of the object under the test.

Using such a way of forming the testing voltage has allowed to lower down the power consumption of VLF-120KP and reduce it physical size.