Abstract: Mineral oil has traditionally been used as a cooling fluid in power transformers, but its low biodegradability and low fire point have motivated the search of alternatives. In this work, six different dielectric fluids have been studied, including four vegetable liquids, from sunflower, rapeseed, soybean, and palm, one synthetic ester and a mineral oil used for comparison. These oils were subjected to an accelerated thermal ageing in glass vessels at 150°C for four weeks (672 hours) in presence of Kraft insulating paper. Different oils parameters were measured during the ageing, i.e. breakdown voltage, dielectric dissipation factor, permittivity, DC resistivity, density, kinematic viscosity, flash and fire points, interfacial tension, acidity, and dissolved gases; additionally, the degree of polymerisation (DP) of the paper was measured. Results showed that the changes of the natural esters properties, except for the palm oil, were similar along the ageing time. Palm oil results were similar to those of the mineral oil, whereas synthetic ester showed a behaviour similar to natural esters. The kraft paper degradation was higher in the mineral oil, followed by the synthetic ester and the palm oil. No significant differences were found in the ageing with the natural esters.
Autoría: Gutierrez C.M., Fernandez A.O., Renedo Estebanez C.J., Salas C.O., Maina R.,
Fuente: IEEE Access, 2023, 11, 9656 - 9671
Editorial: Institute of Electrical and Electronics Engineers, Inc.
Fecha de publicación: 01/02/2023
Nº de páginas: 16
Tipo de publicación: Artículo de Revista
DOI: 10.1109/ACCESS.2023.3239895
ISSN: 2169-3536
Proyecto español: PID2019-107126RB-C22
Proyecto europeo: info:eu-repo/grantAgreement/EC/H2020/823969/EU/Raising knowledge and developing technology for the design and deployment of high-performance power transformers immersed in biodegradable fluids"BIOTRAFO"/BIOTRAFO/
Url de la publicación: http://doi.org/10.1109/ACCESS.2023.3239895.