Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning

Dissolved gas analysis remains the most widely utilized non-intrusive diagnostic method for detecting incipient faults in insulating liquid-immersed transformers. Despite their prevalence, conventional ratio-based methods often suffer from ambiguity and limited potential for automation applicrations...

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Main Authors: Andrew Adewunmi Adekunle, Issouf Fofana, Patrick Picher, Esperanza Mariela Rodriguez-Celis, Oscar Henry Arroyo-Fernandez, Hugo Simard, Marc-André Lavoie
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/13/3535
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author Andrew Adewunmi Adekunle
Issouf Fofana
Patrick Picher
Esperanza Mariela Rodriguez-Celis
Oscar Henry Arroyo-Fernandez
Hugo Simard
Marc-André Lavoie
author_facet Andrew Adewunmi Adekunle
Issouf Fofana
Patrick Picher
Esperanza Mariela Rodriguez-Celis
Oscar Henry Arroyo-Fernandez
Hugo Simard
Marc-André Lavoie
author_sort Andrew Adewunmi Adekunle
collection DOAJ
description Dissolved gas analysis remains the most widely utilized non-intrusive diagnostic method for detecting incipient faults in insulating liquid-immersed transformers. Despite their prevalence, conventional ratio-based methods often suffer from ambiguity and limited potential for automation applicrations. To address these limitations, this study proposes a unified multiclass classification model that integrates traditional gas ratio features with supervised machine learning algorithms to enhance fault diagnosis accuracy. The performance of six machine learning classifiers was systematically evaluated using training and testing data generated through four widely recognized gas ratio schemes. Grid search optimization was employed to fine-tune the hyperparameters of each model, while model evaluation was conducted using 10-fold cross-validation and six performance metrics. Across all the diagnostic approaches, ensemble models, namely random forest, XGBoost, and LightGBM, consistently outperformed non-ensemble models. Notably, random forest and LightGBM classifiers demonstrated the most robust and superior performance across all schemes, achieving accuracy, precision, recall, and F1 scores between 0.99 and 1, along with Matthew correlation coefficient values exceeding 0.98 in all cases. This robustness suggests that ensemble models are effective at capturing complex decision boundaries and relationships among gas ratio features. Furthermore, beyond numerical classification, the integration of physicochemical and dielectric properties in this study revealed degradation signatures that strongly correlate with thermal fault indicators. Particularly, the CIGRÉ-based classification using a random forest classifier demonstrated high sensitivity in detecting thermally stressed units, corroborating trends observed in chemical deterioration parameters such as interfacial tension and CO<sub>2</sub>/CO ratios. Access to over 80 years of operational data provides a rare and invaluable perspective on the long-term performance and degradation of power equipment. This extended dataset enables a more accurate assessment of ageing trends, enhances the reliability of predictive maintenance models, and supports informed decision-making for asset management in legacy power systems.
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spelling doaj-art-af8c3f5f4dc044f9830e70c342e6f0e52025-07-11T14:39:22ZengMDPI AGEnergies1996-10732025-07-011813353510.3390/en18133535Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine LearningAndrew Adewunmi Adekunle0Issouf Fofana1Patrick Picher2Esperanza Mariela Rodriguez-Celis3Oscar Henry Arroyo-Fernandez4Hugo Simard5Marc-André Lavoie6Canada Research Chair Tier 1, in Aging of Oil-Filled Equipment on High Voltage Lines (ViAHT), University of Quebec at Chicoutimi, Chicoutimi, QC G7H 2B1, CanadaCanada Research Chair Tier 1, in Aging of Oil-Filled Equipment on High Voltage Lines (ViAHT), University of Quebec at Chicoutimi, Chicoutimi, QC G7H 2B1, CanadaHydro Quebec Research Institute, Varennes, QC J3X 1S1, CanadaHydro Quebec Research Institute, Varennes, QC J3X 1S1, CanadaHydro Quebec Research Institute, Varennes, QC J3X 1S1, CanadaRio Tinto, Saguenay, QC G7S 2H8, CanadaRio Tinto, Saguenay, QC G7S 2H8, CanadaDissolved gas analysis remains the most widely utilized non-intrusive diagnostic method for detecting incipient faults in insulating liquid-immersed transformers. Despite their prevalence, conventional ratio-based methods often suffer from ambiguity and limited potential for automation applicrations. To address these limitations, this study proposes a unified multiclass classification model that integrates traditional gas ratio features with supervised machine learning algorithms to enhance fault diagnosis accuracy. The performance of six machine learning classifiers was systematically evaluated using training and testing data generated through four widely recognized gas ratio schemes. Grid search optimization was employed to fine-tune the hyperparameters of each model, while model evaluation was conducted using 10-fold cross-validation and six performance metrics. Across all the diagnostic approaches, ensemble models, namely random forest, XGBoost, and LightGBM, consistently outperformed non-ensemble models. Notably, random forest and LightGBM classifiers demonstrated the most robust and superior performance across all schemes, achieving accuracy, precision, recall, and F1 scores between 0.99 and 1, along with Matthew correlation coefficient values exceeding 0.98 in all cases. This robustness suggests that ensemble models are effective at capturing complex decision boundaries and relationships among gas ratio features. Furthermore, beyond numerical classification, the integration of physicochemical and dielectric properties in this study revealed degradation signatures that strongly correlate with thermal fault indicators. Particularly, the CIGRÉ-based classification using a random forest classifier demonstrated high sensitivity in detecting thermally stressed units, corroborating trends observed in chemical deterioration parameters such as interfacial tension and CO<sub>2</sub>/CO ratios. Access to over 80 years of operational data provides a rare and invaluable perspective on the long-term performance and degradation of power equipment. This extended dataset enables a more accurate assessment of ageing trends, enhances the reliability of predictive maintenance models, and supports informed decision-making for asset management in legacy power systems.https://www.mdpi.com/1996-1073/18/13/3535power transformerdissolved gas analysisdiagnostic techniquesphysicochemical and dielectric propertiesmachine learning models
spellingShingle Andrew Adewunmi Adekunle
Issouf Fofana
Patrick Picher
Esperanza Mariela Rodriguez-Celis
Oscar Henry Arroyo-Fernandez
Hugo Simard
Marc-André Lavoie
Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning
Energies
power transformer
dissolved gas analysis
diagnostic techniques
physicochemical and dielectric properties
machine learning models
title Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning
title_full Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning
title_fullStr Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning
title_full_unstemmed Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning
title_short Multiclass Fault Diagnosis in Power Transformers Using Dissolved Gas Analysis and Grid Search-Optimized Machine Learning
title_sort multiclass fault diagnosis in power transformers using dissolved gas analysis and grid search optimized machine learning
topic power transformer
dissolved gas analysis
diagnostic techniques
physicochemical and dielectric properties
machine learning models
url https://www.mdpi.com/1996-1073/18/13/3535
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