The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions

Synthetic ester insulating oils are extensively utilized in power transformers due to their exceptional insulating properties, thermal stability, and environmental compatibility. The dissolved gas analysis (DGA) technique, which is employed to diagnose internal faults in transformers by monitoring t...

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Main Authors: Liping Guo, Hongliang Wang, Weiwei Qi, Jun Zhang, Wu Lu
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/13/3276
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author Liping Guo
Hongliang Wang
Weiwei Qi
Jun Zhang
Wu Lu
author_facet Liping Guo
Hongliang Wang
Weiwei Qi
Jun Zhang
Wu Lu
author_sort Liping Guo
collection DOAJ
description Synthetic ester insulating oils are extensively utilized in power transformers due to their exceptional insulating properties, thermal stability, and environmental compatibility. The dissolved gas analysis (DGA) technique, which is employed to diagnose internal faults in transformers by monitoring the concentration and composition of dissolved gases in oil, is thought to be effective in detecting typical faults such as overheating and partial discharges in synthetic esters. However, owing to the significant differences in the properties of traditional mineral oil and synthetic esters, the existing DGA-based diagnostic methods developed for mineral oils cannot be directly applied to synthetic esters. A deep understanding of the microscopic processes occurring during the gas generation and diffusion of synthetic esters is an urgent necessity for DGA applications. Therefore, in this study, we systematically investigated the diffusion behavior of seven typical fault gases in synthetic ester insulating oils within a temperature range of 343–473 K using molecular dynamics simulations. The results demonstrate that H<sub>2</sub> exhibits the highest diffusion capability across all temperatures, with a diffusion coefficient of 33.430 × 10<sup>−6</sup> cm<sup>2</sup>/s at 343 K, increasing to 402.763 × 10<sup>−6</sup> cm<sup>2</sup>/s at 473 K. Additionally, this paper explores the microscopic mechanisms underlying the diffusion characteristics of these characteristic gases by integrating the Free-Volume Theory, thereby providing a theoretical foundation for refining the fault gas analysis methodology for transformer insulating oils.
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spelling doaj-art-95ca784bb9864a938cb1ac2b83611c1e2025-08-20T02:35:56ZengMDPI AGEnergies1996-10732025-06-011813327610.3390/en18133276The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal ConditionsLiping Guo0Hongliang Wang1Weiwei Qi2Jun Zhang3Wu Lu4Shanghai Electric Transmission and Distribution Experimental Center Co., Ltd., Shanghai 200072, ChinaShanghai Electric Transmission and Distribution Experimental Center Co., Ltd., Shanghai 200072, ChinaCollege of Electrical Engineering, Shanghai University of Electric Power, Shanghai 200090, ChinaCollege of Electrical Engineering, Shanghai University of Electric Power, Shanghai 200090, ChinaCollege of Electrical Engineering, Shanghai University of Electric Power, Shanghai 200090, ChinaSynthetic ester insulating oils are extensively utilized in power transformers due to their exceptional insulating properties, thermal stability, and environmental compatibility. The dissolved gas analysis (DGA) technique, which is employed to diagnose internal faults in transformers by monitoring the concentration and composition of dissolved gases in oil, is thought to be effective in detecting typical faults such as overheating and partial discharges in synthetic esters. However, owing to the significant differences in the properties of traditional mineral oil and synthetic esters, the existing DGA-based diagnostic methods developed for mineral oils cannot be directly applied to synthetic esters. A deep understanding of the microscopic processes occurring during the gas generation and diffusion of synthetic esters is an urgent necessity for DGA applications. Therefore, in this study, we systematically investigated the diffusion behavior of seven typical fault gases in synthetic ester insulating oils within a temperature range of 343–473 K using molecular dynamics simulations. The results demonstrate that H<sub>2</sub> exhibits the highest diffusion capability across all temperatures, with a diffusion coefficient of 33.430 × 10<sup>−6</sup> cm<sup>2</sup>/s at 343 K, increasing to 402.763 × 10<sup>−6</sup> cm<sup>2</sup>/s at 473 K. Additionally, this paper explores the microscopic mechanisms underlying the diffusion characteristics of these characteristic gases by integrating the Free-Volume Theory, thereby providing a theoretical foundation for refining the fault gas analysis methodology for transformer insulating oils.https://www.mdpi.com/1996-1073/18/13/3276synthetic esterdissolved gas analysismolecular dynamicsdiffusion coefficientfree volume
spellingShingle Liping Guo
Hongliang Wang
Weiwei Qi
Jun Zhang
Wu Lu
The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions
Energies
synthetic ester
dissolved gas analysis
molecular dynamics
diffusion coefficient
free volume
title The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions
title_full The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions
title_fullStr The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions
title_full_unstemmed The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions
title_short The Molecular Dynamics of Signature Gas Diffusions in Synthetic-Ester-Based Oil Under a Range of Thermal Conditions
title_sort molecular dynamics of signature gas diffusions in synthetic ester based oil under a range of thermal conditions
topic synthetic ester
dissolved gas analysis
molecular dynamics
diffusion coefficient
free volume
url https://www.mdpi.com/1996-1073/18/13/3276
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