@article{10902/9744,
year = {2015},
month = {10},
url = {http://hdl.handle.net/10902/9744},
abstract = {The transformers lifespan depends importantly on its refrigeration. Mineral oils perform this work in the majority of the power transformers. However, this type of coolant has two main drawbacks: low biodegradability and low ignition point. Several alternative liquids are being developed in order to overcome these drawbacks. This paper compares their thermal-fluid behavior with a mineral oil by means of several parameters, such as temperature, flow rate, fluids velocity, convective heat transfer coefficient (h) and the cooling criterion (P). These are calculated using the numerical results of the simulation of a 3D-model of a Low Voltage Winding that belongs to a power transformer with ONAN cooling. The software COMSOL Multiphysics has allowed the simulation of the geometry using a physical model in which buoyancies and viscous forces are the only considered establishing the natural convection. As a result of the comparison, it is clear that the mineral oil is the best coolant liquid. Among the alternative liquids, silicone oil would be the second best coolant fluid, followed by the synthetic and natural esters, respectively. On the other hand, it seems to be clear that the 3D simulations can be used to compare properly the cooling capacities of the liquids.},
organization = {The research leading to these results has received funding from multiple sources during years but we would specifically like to acknowledge the support received in the later stages from the Spanish Plan Estatal de I+D under the grant agreement DPI2013-43897-P.},
publisher = {Institute of Electrical and Electronics Engineers},
publisher = {IEEE Transactions on Dielectrics and Electrical Insulation, 2015, Vol. 22 (5), 2522-2529},
title = {Thermal-fluid characterization of alternative liquids of power transformers: a numerical approach},
author = {Lecuna Tolosa, Ramón and Delgado San Román, Fernando and Ortiz Fernández, Alfredo and Castro Alonso, Pablo Bernardo and Fernández Diego, Inmaculada and Renedo Estébanez, Carlos J.},
}