Dielectric and Thermal Ageing Characteristics of Al₂O₃ Nanofluid-Impregnated Cellulose for Power Transformer Applications

Shaymaa A. Qenawy, Electrical Power Engineering and Control Department, Pyramids Higher Institute for Engineering and Technology, Giza, EgyptFollow
Basma Eltlhawy, Department of Mechatronics Engineering, Pyramids Higher Institute for Engineering and Technology, Giza, Egypt,
Hussein M. Waly, Electrical Power Engineering and Control Department, Pyramids Higher Institute for Engineering and Technology, Giza, Egypt

Subject Area

Electrical Engineering

Article Type

Original Study

Abstract

As nanotechnology progresses, nanofluids have emerged as promising candidates for transformer insulation due to their enhanced dielectric and thermal properties. This study evaluates the degradation behavior of a mineral oil-cellulose system compared to an alumina (Al₂O₃) nanofluid-cellulose system. Accelerated thermal ageing tests were conducted at 120°C for a 20-day duration, simulating approximately 20 years of field service. Key findings reveal that the nanofluid-impregnated paper exhibited superior mechanical longevity, characterized by a 3% reduction in the tensile strength deterioration rate relative to mineral oil samples. Initially, the AC breakdown voltage (BDV) of the nanofluid was 10.85% higher than that of the base mineral oil; however, a more pronounced decline was observed after 14 days, primarily attributed to nanoparticle agglomeration. Despite a marginal 3% increase in kinematic viscosity, the nanofluid maintained acidity levels within acceptable operational limits (< 0.2 mg KOH/g). These results demonstrate that while Al₂O₃ nanofluids significantly extend the thermal life of solid insulation, long-term colloidal stability remains a critical constraint for practical transformer applications.

Keywords

Nanofluid, Mineral oil, Ac breakdown voltage, Thermal ageing, Impregnated paper

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Recommended Citation

Qenawy, Shaymaa A.; Eltlhawy, Basma; and Waly, Hussein M. (2026) "Dielectric and Thermal Ageing Characteristics of Al₂O₃ Nanofluid-Impregnated Cellulose for Power Transformer Applications," Mansoura Engineering Journal: Vol. 51 : Iss. 5 , Article 16.
Available at: https://doi.org/10.58491/2735-4202.3443

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