Vlf Cable Testing

In the first step a go no go statement is sufficient.

Vlf cable testing. The device under test must withstand a vlf very low frequency ac voltage for a preset testing time without flashover. Hv test lead ground cable figure 4. Vlf cable testing is the cutting edge technology for proof testing of fully operating medium voltage cables and the detection of faulty ones. The major application is for testing solid dielectric cable per ieee 400 2 followed by testing large rotating machinery per ieee 433 1974 and occasionally for testing.

During the test cables are subjected to a test voltage significantly higher than what they experience during normal operating conditions. Vlf testing is not only used for testing solid dielectric cable any application requiring ac testing of high capacitance loads can be tested using very low frequency. Vlf cable testing makes use of ac voltages in a frequency range of 0 01. Connection setup for a vlf cable connecting a vlf test instrument to a cable refer to ieee 400 2 for safety guidelines.

Making them useful especially for field testing where transport and space can be issues. This kind of test is suited for testing high capacitance loads such. Perform the test as instructed to make best use of vlf technology. If a vlf test is too low in voltage and or too short in duration more harm than good may result.

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. 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. When vlf withstand testing cable the proper test voltage and time duration are critical for the success of the test. The vlf test instrument should be solidly grounded before connecting up any cables.