Dielectric Design of Ester-Filled Power Transformers: AC Stress Analysis

Montero, Andrés; García, Belén; Burgos, Juan Carlos; González-García, Carlos

doi:10.1109/tpwrd.2022.3145880

Cited by 10 publications

(4 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, the dielectric permittivity is important in the dielectric design of transformers, as the relationship between the permittivity of the fluid and paper will largely determine the distribution of the electric field throughout the insulating system [68]. This determines the electrical stress the materials withstand and the occurrence of partial discharges.…”

Section: Dielectric Permittivitymentioning

confidence: 99%

Analysing the Suitability of Using Different Biodegradable Fluids for Power Transformers with Thermally Upgraded Paper

Méndez,

Olmo,

Antolín

et al. 2024

Sustainability

View full text Add to dashboard Cite

Mineral oil has been used for many years in various electrical equipment, including transformers, as a cooling and insulation medium. However, its low biodegradability and poor performance in terms of fire protection have prompted the search for fluids to replace it, with vegetable oils being prominently considered. In this study, the dielectric, chemical, and physical properties of four vegetable oils obtained from different seeds (sunflower, rapeseed, soybean, and palm) and a biodegradable synthetic fluid are analysed throughout their lifespan in transformers. Their performances are compared with a traditional mineral oil to assess which one is more suitable for use in transformers employing this type of paper. To achieve this, the fluids were subjected to thermal ageing in combination with copper and a thermally upgraded kraft (TUK) paper, with its degradation controlled by measuring the degree of polymerisation. The results demonstrate that the origin of the vegetable oils affects their properties and degradation rates. It was found that most of the alternative fluids are suitable for use in transformers with the TUK paper and that they can increase their lifespan.

show abstract

Section: Dielectric Permittivitymentioning

confidence: 99%

Analysing the Suitability of Using Different Biodegradable Fluids for Power Transformers with Thermally Upgraded Paper

Méndez,

Olmo,

Antolín

et al. 2024

Sustainability

View full text Add to dashboard Cite

show abstract

“…Numerical simulations carried out have shown that the temperatures reached in a transformer using esters could be similar, or even lower, to those reached with mineral oils in adapted winding designs [12], [13], [14] Some manufacturers apply special treatments to improve the viscosity or the oxidation stability of these alternative liquids [15]. The effect of the fluid used on the degradation of the solid insulation, measured by the control of the chemical [16], mechanical [17] or light techniques [18] after a thermal [19] or electrical [20] ageing process, have also been afforded.…”

Section: Introductionmentioning

confidence: 95%

Understanding the Ageing Performance of Alternative Dielectric Fluids

et al. 2023

View full text Add to dashboard Cite

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.INDEX TERMS Insulating paper, natural esters, thermal ageing, transformers.

show abstract

“…Another of its functions is to minimise the contact of cellulose and other materials with oxygen to reduce the risk of oxidation. For the liquid part of insulation, mineral oils have been the most widely used for over a century 1 . However, the controversy over the negative impact of mineral oils on the environment is nowadays a hot topic taken very seriously by environmentalists 2 .…”

Section: Introductionmentioning

confidence: 99%

Statistical analysis of the impact of FeO3 and ZnO nanoparticles on the physicochemical and dielectric performance of monoester-based nanofluids

Jiosseu

Jean-Bernard

Mengounou

et al. 2023

Sci Rep

View full text Add to dashboard Cite

This article deals with a comparative study of the physicochemical and electrical properties of monoesters of castor oil compared with their counterparts based on FeO3 and ZnO nanoparticles. The results are also compared with those in the literature on triesters, and also with the recommendations of the IEEE C 57.14 standard. The data is analysed statistically using a goodness-of-fit test. The analysis of the viscosity data at 40 °C shows an increase in viscosity. For concentrations of 0.10 wt%, 0.15 wt% and 0.20 wt% these are respectively 5.4%, 9.69%, 12.9% for FeO3 NFs and 7.6%, 9.91% and 12.7% for ZnO NFs. For the same concentrations, the increase in acid number is respectively 3.2%, 2.9%, 2.5% for FeO3 samples and 3.18%, 2.0%, 1.2% for ZnO samples. For the same concentrations, the fire point shows an increment of 4%, 3% and 2% for FeO3 samples and a regression of 8.75%, 6.88% and 5.63% for ZnO samples. As for the breakdown voltage, for the same concentrations we observe respectively an increment of 43%, 27%, 34% for the FeO3. The results show an improvement on partial discharge inception voltage with FeO3 of 24%, 8.13% and 15.21% respectively for the concentrations 0.10 wt%, 0.15 wt% and 0.20 wt%.

show abstract

Dielectric Design of Ester-Filled Power Transformers: AC Stress Analysis

Cited by 10 publications

References 20 publications

Analysing the Suitability of Using Different Biodegradable Fluids for Power Transformers with Thermally Upgraded Paper

Analysing the Suitability of Using Different Biodegradable Fluids for Power Transformers with Thermally Upgraded Paper

Understanding the Ageing Performance of Alternative Dielectric Fluids

Statistical analysis of the impact of FeO3 and ZnO nanoparticles on the physicochemical and dielectric performance of monoester-based nanofluids

Contact Info

Product

Resources

About