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Experimental Investigation of the Effect of Transient Overvoltages on XLPE-insulated HVDC Cables
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  • Bassel Diban ,
  • Giovanni Mazzanti ,
  • Laura Mazzocchetti ,
  • Paolo Seri
Bassel Diban
University of Bologna, University of Bologna

Corresponding Author:[email protected]

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Giovanni Mazzanti
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Laura Mazzocchetti
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Paolo Seri
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Abstract

HVDC cables are subject to several types of impulses superimposed on the rated DC voltage during their service lifetime. Temporary Overvoltages TOVs and Superimposed Switching impulses SSIs are considered some of the most challenging due to the relatively long impulse duration. This paper aims at investigating experimentally the effect of TOVs and SSIs on XLPE insulation for extruded HVDC cables. 0.15-mm-thick DC-XLPE specimens, aged by applying TOVs and SSIs, are characterized using dielectric analyzer and Fourier Transform InfraRed spectroscopy (FTIR) to detect the aging effects on the insulation. Results show an increase in the imaginary part of permittivity, ε”, accompanied with the appearance of additional dipolar polarization losses peaks. The amplitude and frequency of the aforementioned peaks vary with the amplitude and the number of applied TOVs and SSIs. An increase in electrical conductivity is also noticed with aging. FTIR results show absorbance peaks in the aged specimens likely due to the intramolecular bonds rupture accompanied with the formation of aging products.
Aug 2023Published in IEEE Transactions on Dielectrics and Electrical Insulation volume 30 issue 4 on pages 1779-1786. 10.1109/TDEI.2023.3264959