Vlf Cable Test Set

The vlf test instrument should be solidly grounded before connecting up any cables.

Vlf cable test set.

Very low frequency is the preferred method over 60hz for two reasons. Hva68 2 cable tester new hva90 insulation tester. At a typical vlf frequency of 0 1hz it takes 600 times less power to test the same cable compared to 60 hz. There are no rules of thumb to be used.

The hva28td vlf high voltage test set is an ultra compact lightweight 0 1 hz vlf cable tester with integrated tan delta diagnostics. 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 voltages and time durations are set by ieee standard 400 2 2013. A typical 15 kv medium voltage cable in usa has an insulation thickness of 0 22 5 6 mm and therefore during a vlf test time of 30 minutes all defects within the cable should grow to failure.

These numbers result from many years of vlf field use and research. 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 hv test lead outside shield conductor is connected to the concentric neutral ground point of the cable under test. 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. This kind of test is suited for testing high capacitance loads such. Hva40 5 hipot tester new hva45td vlf high voltage test set new hva60 ac hipot. 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.

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. 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. Ground cable figure 4. Hva28 td vlf test set at a glance.

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.