Abstract
Ester insulating oils are the preferred dielectric fluids of choice for oil-immersed transformers because of their superior fire safety, environmental friendliness, sustainability, and satisfying operating efficiency compared with traditional mineral insulating oil. However, the ease of streamer propagation and low breakdown voltage in ester fluids at positive lightning impulse (LI) voltage pose a crucial challenge to the safe operation of transformers, significantly limiting their use in power transformers. Currently, most available studies have focused on the morphological analysis of streamers without further investigation at the molecule level. In this work, we investigated the effect of ionization potential (IP) and electron affinity (EA) of molecules in three types of ester fluids—palm fatty acid ester (PFAE), soybean (FR3) and rapeseed (RDB) insulating oils—on streamer propagation at positive LI voltage. The calculated IP of PFAE oil (8.8 eV) is higher than the other two oils (7.5 eV). 66% faster streamer propagation and 25% lower positive LI breakdown voltage were found in PFAE oil compared with FR3 and RDB oils under positive LI voltage. Under the same applied voltage, the streamer in PFAE oil travelled faster and stopped at a farther distance than in FR3 and RDB oils. The lower EA and viscosity of PFAE oil equipped electrons with higher kinetic energy, leading to a fiercer collision between electrons and molecules and thus a large number of excited molecules. In contrast, relatively higher EAs and viscosities of FR3 and RDB oils limited electron-molecule collision, resulting in a lack of excited molecules for streamer propagation.
Similar content being viewed by others
Availability of Data and Material
All data generated or analyzed during this study are included in this published article.
Code Availability
Not applicable for that section.
References
Z. Shen, F. Wang, Z. Wang, J. Li, A critical review of plant-based insulating fluids for transformer: 30-year development. Renew. Sustain. Energy Rev. 141, 110783 (2021)
K. Wang, F. Wang, Z. Shen, Z. Lou, Q. Han, J. Li, P. Rozga, Breakdown and streamer behavior in homogeneous synthetic trimethylolpropane triesters insulation oil. IEEE Trans. Dielectr. Electr. Insul. 27(5), 1501–1507 (2020)
C.T. Duy, O. Lesaint, A. Denat, N. Bonifaci, Streamer propagation and breakdown in natural ester at high voltage. IEEE Trans. Dielectr. Electr. Insul. 16(6), 1582–1594 (2009)
O. Lesaint, Prebreakdown phenomena in liquids: propagation ‘modes’ and basic physical properties. J. Phys. D Appl. Phys. 49(14), 144001 (2016)
O. Lesaint, G. Massala, Positive streamer propagation in large oil gaps: experimental characterization of propagation modes. IEEE Trans. Dielectr. Electr. Insul. 5(3), 360–370 (1998)
A. Reffas, H. Moulai, A. Beroual, Comparison of dielectric properties of olive oil, mineral oil, and other natural and synthetic ester liquids under AC and lightning impulse stresses. IEEE Trans. Dielectr. Electr. Insul. 25(5), 1822–1830 (2018)
H.S. Smalø, P.O. Astrand, S. Ingebrigtsen, Calculation of ionization potentials and electron affinities for molecules relevant for streamer initiation and propagation. IEEE Trans. Dielectr. Electr. Insul. 17(3), 733–741 (2010)
T. Kanoh, H. Iwabuchi, Y. Hoshida, J. Yamada, T. Hikosaka, A. Yamazaki, Y. Hatta, H. Koide, Analyses of electro-chemical characteristics of palm fatty acid esters as insulating oil, in 2008 IEEE International Conference on Dielectric Liquids pp. 1–4. IEEE (2008)
Q. Liu, Z.D. Wang, Streamer characteristic and breakdown in synthetic and natural ester transformer liquids under standard lightning impulse voltage. IEEE Trans. Dielectr. Electr. Insul. 18(1), 285–294 (2011)
W.F. Schmidt, Electronic conduction processes in dielectric liquids. IEEE Trans. Electr. Insul. 5, 389–418 (1984)
A. Becke, Density-functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 98, 5648 (1993)
J. Li, Y. Wang, F. Wang, S. Liang, X. Lin, X. Chen, J. Zhou, A study on ionization potential and electron trap of vegetable insulating oil related to streamer inception and propagation. Phys. Lett. A 381(44), 3732–3738 (2017)
Acknowledgements
The authors wish to thank co-workers at the Electric Power Test & Research Institute, Guangzhou Power Supply Co., Ltd., for helping with experimental apparatuses and materials.
Funding
This study was supported by the Technology Project of China Southern Power Grid Corporation (Grant No. GZJKJXM20170055).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflicts of interest
The authors declare that they have no conflict of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Mo, W., Song, H., Huang, Q. et al. The Effect of Electronic Characteristics of Molecules in Ester Insulating Oils on Streamer Propagation. Trans. Electr. Electron. Mater. 23, 650–657 (2022). https://doi.org/10.1007/s42341-022-00402-y
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s42341-022-00402-y