Assessing Transformer Aging Using Dielectric Oil Characteristics: Influence of Operating Voltage Levels and Purification

Dielectric characteristic testing of transformer oil is a crucial diagnostic tool for assessing transformer health. While previous studies have investigated the correlation between oil quality parameters and aging factors, limited research has examined the direct influence of operating voltage level...

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Bibliographic Details
Main Authors: Muhammad A. Akmal Putra, Suwarno, Rahman Azis Prasojo
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/10950444/
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Summary:Dielectric characteristic testing of transformer oil is a crucial diagnostic tool for assessing transformer health. While previous studies have investigated the correlation between oil quality parameters and aging factors, limited research has examined the direct influence of operating voltage levels on dielectric oil degradation. Additionally, the effect of oil purification on aging assessments is often overlooked, leading to potential misinterpretations in condition assessment. This study analyzes historical dielectric test data from 4315 oil samples collected from power transformers operating at 500 kV, 150 kV, and 70 kV within Indonesia’s electrical grid. The data is categorized into two groups: one without considering purification and another combining purified and unpurified oil samples. Statistical analysis using linear regression is employed to assess correlations among key parameters. The findings reveal that higher operating voltage levels accelerate the degradation of dielectric oil, with transformers operating at 500 kV exhibiting the most rapid decline in oil quality. Furthermore, purification significantly alters certain dielectric parameters, particularly BDV and water content, whereas the color scale remains largely unaffected. The study also establishes that parameters such as acidity, water content, and interfacial tension (IFT) are reliable indicators of transformer aging only in unpurified oil samples. Conversely, the color scale proves to be a more consistent indicator of overall insulation system aging, making it a valuable parameter for maintenance decision-making. These results provide a refined approach for utilities in transformer condition assessment, ensuring that the impact of purification is accounted for to avoid misleading aging evaluations. The results also highlight the necessity for voltage-specific maintenance strategies to enhance transformer reliability and lifetime.
ISSN:2169-3536