Vlf Cable Test

This combination of size and power makes very low frequency cable testing perfect for testing longer sections of cable and apparatus.

Vlf cable test. The most commonly used commercially available vlf ac voltage test frequency is 0 1 hz. In the first step a go no go statement is sufficient. 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. The hv test lead outside shield conductor is connected to the concentric neutral ground point of the cable under test.

Vlf testing can be classified as a withstand or diagnostic test meaning it may be performed as a proof test for acceptance or as a maintenance test for assessing the condition of cable. This kind of test is suited for testing high capacitance loads such. The main conductor of the hv test lead is then connected to the conductor of the cable under test. Vlf testers are smaller and more practical than ac testers but output the same amount of power as a 50 hz mains device.

Vlf cable testing very low frequency is a technique for testing of medium and high voltage mv and hv cables. Vlf testing uses very low frequencies as part of an ac cable maintenance routine. The vlf test instrument should be solidly grounded before connecting up any cables. Unlike with dc voltage testing very low frequency is not destructive to good insulation and does not lead to premature failures.

Vlf systems are advantageous in that they can be manufactured to be small and lightweight. Vlf ac voltage testing methods utilize ac signals at frequencies in the range of 0 01 hz to 1 hz. Vlf cable testing is the cutting edge technology for proof testing of fully operating medium voltage cables and the detection of faulty ones. Vlf testing uses very low frequencies as part of an ac cable maintenance routine.

The device under test must withstand a vlf very low frequency ac voltage for a preset testing time without flashover. Vlf testers are smaller and more practical than ac testers but output the same amount of power as a 50 hz mains device. Vlf ac test voltages with cosinerectangular and the sinusoidal wave shapes are most commonly used. During the test cables are subjected to a test voltage significantly higher than what they experience during normal operating conditions.

Making them useful especially for field testing where transport and space can be issues. Very low frequency vlf withstand testing is the application of an ac sinusoidal waveform generally at 0 01 0 1 hz to assess the quality of electrical insulation in high capacitive loads such as cables.