Exploration on use of ferrofluid in power transformers

Abstract

During normal operating conditions, the thermal fluctuation in a power transformer is controlled by the mineral insulating oil that acts as cooling media and keeps the transformer in thermal equilibrium. Feasibility of ferrofluid in power transformers and compatibility with the transformer components have been quite an area of interest even after it has surfaced as a possible dielectric fluid with enhanced heat dissipation capacity. The experimental contributions in this research are dedicated towards the comparison of ferrofluid and naphthenic oil with kraft paper where major emphasis has been laid on the results obtained from long term laboratory scale ageing of ferrofluid for 61days at 393 K (120°C) with respect to the dissolved gas analysis (DGA) , moisture, and degree of polymerization (DP) of solid insulation along with oxidation stability and Rotating Bomb Oxidation Test (RBOT) with kraft paper.

Analysis of Thermal Field in Mineral Transformer Oil Based Magnetic Fluids

“…The difference is 129.9 W/m 2 which confirms that magnetic fluid has better cooling ability than transformer oil [3,4,7].…”

“…The magnetic fluid has magnetic properties of magnetic nanoparticles and fluidity of carrier fluid [1,2]. Magnetic fluids are characterized by higher heat transfer and the ability to use external magnetic field to create forced circulation [3][4][5].…”

Studies on the Influence of Copper and Insulation Paper on the Accelerated Thermal Ageing of Some Insulating Fluids

“…The relatively small changes in viscosity during the thermal ageing of the ester-based insulating fluids in simultaneous contact with copper and insulation paperof maximum 5.7% in relation to over 35% in the mineral oils case-suggests they ensure a high stability of the magnetic nano-powders suspension when they are used in insulating ferrofluids [26][27][28].…”

Mineral and Ester Nanofluids as Dielectric Cooling Liquid for Power Transformers

“…In other cases, the increase of moisture during aging could explain the diminution of the dielectric strength [ 86 ]. The degree of polymerization (DP) of aged paper samples, which represents how well their molecular structure has been conserved, has also shown improvements [ 132 ] and deterioration [ 86 , 196 ], that were explained respectively by the supposed capacity of the nanofluid to delay the degradation, and by the particles performing as hot-spots on the surface of the paper. The analysis of the degradation gases produced that were during the ageing process of nanofluids was also not conclusive [ 50 ].…”