PD measurement and commissioning test for cables

摘要

The enhancement of AC commissioningrntests lies in partial discharge measurements. KEMArnhas developed a system for PD measurements to berncombined with their series resonant test set. Arncombination of instruments have been selectedrnresulting in a good signal-to-noise ratio. Thisrnequipment comprises a coupling capacitor withrnquadrupole and an advanced measuring instrument asrndetector.rnField experience so far has shown an average noisernlevel of 20pC. The calibration of these measurementsrnis based on the use of a 'traditional' calibrator. Thernattenuation in power cables results in an uncertaintyrnrelated to this calibration factor. Therefore, thernmaximum length which can be measured is 3 to 4km.rnAlthough it is not always possible to exclude allrnpossible disturbances, various measures can (andrnshould) be taken to prevent corona from disturbing thernmeasurements.