The CDA system is used for testing medium voltage PILC, XLPE and EPR cables as well as mixed cable structures. A condition assessment of aged cables can be performed as well as PD tests for the commissioning of new cables. The system is commercial available since four years. Built into a test van, it is in use at several utilities in America and Europe. The new CDA waveform with its advantages and disadvantages will be explained to the audience, followed by a description of the standard test procedure. Several test results will be discussed. At last, an outlook of future developments will be given. (slides in PowerPoint format)
These slides are available in PowerPoint (7 MB) and as a much smaller PDF (515 kB)
Most of these insulation problems are accompanied by the presence of partial discharges. In particular, the presence of partial discharges can be described by PD inception/extinction voltages, PD amplitude and PD phase-resolved patterns. Performing PD diagnostics several aspects are of importance:
It is known, that to obtain a sensitive picture of discharging faults in power cables the PD should be ignited, detected and located at power frequencies which are comparable to operating conditions at 50 or 60 Hz. In this way realistic magnitudes in [pC]/[nC] and reproducible patterns of discharges in a power cable can be obtained.
In this contribution PD detection, measurement and analysis using oscillating wave test method is presented as new PD test procedure of medium voltage PILC and polymeric insulated cables. In particular PD inception conditions, PD magnitudes, PD phase-resolved patterns at slowly decaying voltages at different oscillating frequencies (50Hz....500Hz) as well as the PD-location mappings are compared for several insulation defects. In addition, based on systematic field experiences with
The general applicability of PD detection at oscillating
voltages will be discussed. (PowerPoint format 13 MB,
PDF format, 608 kB)