Positive and negative effects of dielectric breakdown in transformer oil based magnetic fluids
- School of Mechanical and Automotive Engineering, Gangneung-Wonju National University, Wonju 220711 (Korea, Republic of)
- Graduate School of Automotive Engineering, Gangneung-Wonju National University, Wonju 220711 (Korea, Republic of)
- Department of Electrical Engineering, Kyungpook National University, Daegu 702701 (Korea, Republic of)
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136791 (Korea, Republic of)
The transformer oil based magnetic fluids can be considered as the next-generation insulation fluids because they offer exciting new possibilities to enhance dielectric breakdown voltage as well as heat transfer performance compared to pure transformer oils. In this study, we have investigated the dielectric breakdown strength of the fluids with the various volume concentrations of nanoparticles in accordance with IEC 156 standard and have tried to find the reason for changing the dielectric breakdown voltage of the fluids from the magnetic field analysis. It was found that the dielectric breakdown voltage of pure transformer oil is around 12 kV with the gap distance of 1.5 mm. In the case of our transformer oil-based magnetic fluids with 0.08% < Φ < 0.6% (Φ means the volume concentration of magnetic nanoparticles), the dielectric breakdown voltage shows above 40 kV, which is 3.3 times higher positively than that of pure transformer oil. Negatively in the case when the volume concentration of magnetic nanoparticles is above 0.65%, the dielectric breakdown voltage decreases reversely. From the magnetic field analysis, the reason might be considered as two situations: the positive is for the conductive nanoparticles dispersed well near the electrodes, which play an important role in converting fast electrons to slow negatively charged particles, and the negative is for the agglomeration of the particles near the electrodes, which leads to the breakdown initiation.
- OSTI ID:
- 22215529
- Journal Information:
- Materials Research Bulletin, Vol. 47, Issue 10; Conference: IFFM2011: 2011 international forum on functional materials, Jeju Island (Korea, Republic of), 28-31 Jul 2011, AFM-2: 2. special symposium on advances in functional materials, Jeju Island (Korea, Republic of), 28-31 Jul 2011; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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