Corona discharge activity in nanoparticle dispersed transformer oil under composite voltages

Titania (TiO 2 ) nanoparticles with cetyl trimethyl ammonium bromide (CTAB) surfactant dispersed in transformer oil has higher corona inception voltage than the normal transformer oil, under AC, DC, and composite AC and DC voltages. It is observed that corona inception voltage is lower under composi...

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Bibliographic Details
Published in:IEEE transactions on dielectrics and electrical insulation 2018-10, Vol.25 (5), p.1731-1738
Main Authors: Swati, Kumari, Sarathi, R., Yadav, K. Sahitya, Taylor, Nathaniel, Edin, Hans
Format: Article
Language:English
Subjects:
Cetyltrimethylammonium bromide
Corona
Discharge
Dispersion
Electric potential
Flash point
Frequencies
nanofluid
Nanofluids
Nanoparticles
Oil insulation
Oils
partial discharge
Power transformer insulation
Stellar coronas
Surface tension
Surfactants
titania nanoparticles
Titanium dioxide
transformer oil
Transformers
Turbidity
UHF technique
Very high frequencies
Voltage measurement
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Summary:Titania (TiO 2 ) nanoparticles with cetyl trimethyl ammonium bromide (CTAB) surfactant dispersed in transformer oil has higher corona inception voltage than the normal transformer oil, under AC, DC, and composite AC and DC voltages. It is observed that corona inception voltage is lower under composite voltages compared to AC and DC voltages. The corona activity radiates ultra high frequency (UHF) signals with its dominant frequency near 1 GHz. Operating a spectrum analyzer in zero span mode, the UHF signals generated from the corona activity, the number of discharges is observed to be more under composite voltages than under AC voltages, both at inception and at higher voltages. A reduction in interfacial tension and an improvement in flash point is observed in nano-titania with surfactant dispersed transformer oil. The addition of surfactant reduces the turbidity of the nanofluid. Phase Resolved Partial Discharge (PRPD) analysis with UHF signals measured, indicates that corona discharge activity occurs around the peak and the pre-peak rising portions of the supply voltage. It is observed that more discharges occur in the positive half cycle for AC superimposed with positive DC voltage and in the negative half cycle for AC superimposed with negative DC voltage. The magnitude of UHF signals formed due to corona activity is less with nanofluid, irrespective of voltage profiles.
ISSN:1070-9878
1558-4135
1558-4135
DOI:10.1109/TDEI.2018.007123