Comparative investigations on high voltage cable with needle defect using damped-AC and 50-hz-AC

Summary

Commissioning tests for High Voltage (HV)-cables require high reactive power and high voltage level to detect service endangering defects. On-site test voltage sources (Resonant AC and Damped AC) have been developed aiming to detect those defects in laid HV-cables on site. Nowadays the detection is based more and more on PDmeasurement than simply waiting for the breakdown during withstand test. Thus, the intention of on-site testing is to detect PD resulting from severe failures or to breakdown such failures which would cause a breakdown, when service power (50Hz) and voltage levels at and above Uo is applied. This paper shows the ability of Damped AC (DAC) test voltage and 50-Hz-AC to detect failures which are service endangering for HV-XLPECables. It compares the results of many tests on HV-Cables with needle defects in terms of PD inception voltage levels and growth rate of the initiated electrical treeing (ET) during application of 50-Hz-AC and DAC-Test voltage. Both test voltages are suitable to detect this defect, but interesting differences appear regarding the growth rates of the initiated ET.

Additional informations

Authors

FABIANI, MOLINA ZUBIRI

Keywords

HV cables, DAC, On-site-test, Needle failure, PD-monitoring