Healing of water tree aged cables using rejuvenation nanofluid. (October 2021)

• Record Type: Journal Article
• Authors: Zhou, Kai; Yuan, Hao; Akram, Shakeel; Meng, Pengfei; Mahmood, Atif; Aamir, M.; Imran, M.
• Is Part Of: Polymer testing. Volume 102(2021)
• Publication Date: 2021-10
• Subjects: High voltage power cables -- Cable insulation -- Nanofluid -- Tetraethyl orthosilicate (TEOS) -- Rejuvenated sample -- SEM -- Tanδ -- FTIR; Polymers -- Testing -- Periodicals; Polymères -- Tests -- Périodiques; 620.1920287
• DOI: 10.1016/j.polymertesting.2021.107324
• Languages: English
• ISSNs: 0142-9418

Abstract

Abstract: The insulation of high voltage power cables is aged due to the impact of water treeing. The voids created due to water treeing can be filled with the injection of nanofluids and restore the insulation of cables. In this work, cross-linked polyethylene (XLPE) cable insulation is restored with the help of tetraethyl orthosilicate (TEOS) rejuvenation nanofluid. The morphological changes in aged and rejuvenated samples are analyzed with the help of scanning electron microscopy (SEM). Moreover, the molecular changes in the aged and rejuvenated samples are detected using Fourier transform infrared (FTIR) spectroscopy. Both the samples are also tested with the help of electrical breakdown tests. The results indicate a positive recovery in the insulation of cables with the injection of TEOS nanofluid. The tan δ results showed a decrease in values after the injection of nanofluid in the aged sample. Moreover, the tan δ values of rejuvenated samples are even better than the unaged cables. SEM results also showed a recovery in the voids of the aged sample due to the injection of nanofluid. FTIR results confirmed that the nanofluid penetrated in the insulation of the cable and the peaks of silicone and alumina bonds are seen in the spectrographs. Highlights: Water tree aged cable sample is used to study the micro voids filling process by injecting the nanofluid and restore the cable insulation after drying the fluid contents. Microstructure analysis of the aged and rejuvenated insulations is carried out by SEM and the chemical bonds of the aged and rejuvenated samples is detected using FTIR spectroscopy. Tanδ results have revealed that the dielectric loss for both groups of samples reduce after injecting rejuvenated nanofluid and their values are even lower than the original cable sample value. Thus, both nanofluids are effective to restore aged cable samples. From microscopic (SEM) results we observed that both nanofluids are effective to fill the micro voids of aged cable However, in terms of better dispersion Group B presented better filling and less agglomeration. For dielectric properties testing, both groups have improved their performance. But Group B indicates better performance and shown that new rejuvenation nanofluid can eliminate the water and form inorganic-organic hybrids to fill the voids of water tree.