|
Evaluating the state of power cable insulation using time domain reflectometry (TDR) technique V. Kolev, P. Nakov, R. Papazyan |
|
The paper gives the sequence of measuring procedures and the results of the application of TDR techniques for low voltage power cables. The main idea of this measuring procedure is based on the assumption that the fault impedance is reduced significantly after applying voltage with a particular form. That change is used later on as criteria for the cable resource (remaining time of service). |
he paper describes the
possibility of evaluating passive fault conditions in the power cable
insulation. In operational conditions faults does not necessarily generate
partial discharges (PDs) - these are called passive faults. When testing
low voltage power cables it is hard to activate PDs, because of the low
testing voltages. In order to eliminate misevaluation of the state of the
power cable insulation a certain method for detection and evaluation of
passive faults has to ba applied. A typical example od a passive fault is
the "water tree". Increasing in the precision of the testing equipment
allows the application of TDR techniques for the power cable impedance
along its length.