High Voltage Cables

 High Voltage Cables

There are different causes for faulty cable insulations. Hence, there are various test and measurement methods to prove fully functional cables or to detect faulty ones. One needs to distinguish between cable testing and cable diagnosis. While cable testing methods result in a go/no go statement cable diagnosis methods allow judgement of the cables current condition. In some cases it is even possible to locate the position of the fault in the insulation... One of the favorite testing methods is VLF cable testing. Using a very low frequency voltage with frequencies in the range of 0.1 to 0.01 Hz protects the device under test from deteriorating due to the test itself, as it used to be with DC testing methods in the older days. Depending on the sort of treeing in the insulation two cable diagnostics methods are common..Water trees can be detected by tan delta measurement. Interpretation of measurement results yield the possibility to distinguish between new, strongly aged and faulty cables and appropriate maintenance and repair measures may be planned. Damages to the insulation and electrical treeing may be detected and located by partial discharge measurement. Data collected during the measurement procedure is compared to measurement values of the same cable gathered during the acceptance-test. This allows simple and quick classification of the dielectric condition of the tested cable. .