The VLF service, per the IEEE 400.2 standard, is a diagnostic technique used on power cables to detect insulation damage without affecting the quality of the insulating material, since it does not cause magnetization damage. This test measures insulation losses at different frequencies ranging from 0.01 to 0.1 Hz, and also serves as a means of detecting faults in the cable itself.
NOM-001-SEDE-2012 (Mexican electrical installations standard) states that electrical installations must be tested before being placed in service and after any modification, to verify that the work was properly carried out.
Very low frequency (VLF) testing of medium- and high-voltage cables is a method of verifying the integrity of cable insulation, usually performed on installations after the cables have been pulled into their conduits. The VLF test is a withstand test generally performed at a frequency between 0.1 Hz and 0.01 Hz instead of 50/60 Hz.
We have equipment in immediate inventory to perform the tests or to offer for rental at a lower cost.
Hipot-VLF testing measures the insulation resistance of medium-voltage XLPE cables or other insulation types, such as polymer cables (PE, XLPE, TRXLPE, EPR, etc.).
This is an applied-potential test because the conductor is energized. During the test, the test voltage exceeds the operating voltage in order to stress the cable at a higher potential. The test is performed to detect insulation faults such as tears in the insulating jacket, cuts in the cable, improperly installed terminations, etc. If no faults are found, the cable is ready to be energized.
