Vlf Cable Test Set

Connection setup for a vlf cable connecting a vlf test instrument to a cable refer to ieee 400 2 for safety guidelines.

Vlf cable test set.

Hva200 high voltage test set new hva systems detect faults in cable networks in a non destructive yet efficient way and fulfill all the requirements of modern cable. The increased load capability in field applications in which 60 hertz is too bulky and expensive making it nearly impossible to test a cable of considerable length. With monitored withstand test mwt testing and diagnostics in compliance with ieee400. Ground cable figure 4.

Critically the test object still receives the alternating sinusoidal voltage that would be supplied through everyday use but the size of the test equipment is. The vlf test instrument should be solidly grounded before connecting up any cables. Hva28 td vlf test set at a glance. The hv test lead outside shield conductor is connected to the concentric neutral ground point of the cable under test.

Very low frequency is the preferred method over 60hz for two reasons. When comparing this figure to power frequency ac or 0 1 hz vlf cos rectangular the tree growth rate is only 2 2 5 9 and 3 4 7 8 mm h. Vlf cable test voltages and time durations are set by ieee standard 400 2 2013. There are no rules of thumb to be used.

A very low frequency vlf withstand test is an ac withstand test usually carried out at a frequency between 0 1 hz and 0 01 hz. Hva68 2 cable tester new hva90 insulation tester. Hva40 5 hipot tester new hva45td vlf high voltage test set new hva60 ac hipot. Subsequent work by the cdfi has shown there to be no significant change in the efficacy of a vlf test conducted over the frequency range 0 1 to 0 01 hz when the ieee 400 2 voltages and times are used.

Because vlf testing supplies a working frequency of 0 1hz as opposed to the 50 60hz usually required for live transmission the physical size of the vlf test set is massively reduced. This kind of test is suited for testing high capacitance loads such. These numbers result from many years of vlf field use and research. Ieee 400 2 establishes some suggested test voltages and times.

At a typical vlf frequency of 0 1hz it takes 600 times less power to test the same cable compared to 60 hz.