• Haw Jia Yong Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Parit Raja, Malaysia
  • Mohd Fairouz Mohd Yousof Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Parit Raja, Malaysia
  • Rahisham Abd Rahman Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Parit Raja, Malaysia
  • Norhafiz Azis Department of Electrical and Electronic Engineering, Universiti Putra Malaysia, Serdang, Malaysia
  • Mohd Aizam Talib TNB Labs Sdn. Bhd., Kajang, Malaysia



Insulation oil, dissolved gas analysis (DGA), stray gas, thermal stress, transformer materials


Insulation oil is one of the most important components in an oil-insulated transformer. With the use of the dissolved gas analysis (DGA) tool, the condition of the transformer can be studied and predicted to prevent unwanted events from occurring. However, due to the rising of issues related to stray gassing phenomenon that causes false interpretations in the transformer condition, there is a need to find out the factors contributing to the formation of the stray gases in the transformer oil. In this research paper, thermal stress (85℃ and 120℃) on transformer oil with different transformer materials are studied to determine the effect towards the formation of stray gases in the transformer oil. The materials studied include diamond dotted paper, metal plate, coated metal plate, insulation glue and core metal. Both the uninhibited oil and inhibited oil are used for comparison. The metal plate, coated metal plate and core metal were found to be causing the generation of H2 gas at 120℃ while the cellulose ageing of insulation paper is causing the generation of CO and CO2 gases at 85℃ and above. The CH4 gas was found to be generated only at 120℃ and the insulation glue was determined to be the main cause for the C2H4 gas generation at 85℃ and above.


D. K. Mahanta and S. Laskar. 2018. Transformer Oil Quality Measurement Based on Temperature Rise Test. 2018 2nd International Conference on Power, Energy and Environment: Towards Smart Technology (ICEPE). 1-4.


M. A. Talib, A. S. A. B. A. Bakar and S. G. Kannan. 2013. Condition Assessment of High Voltage Instrument Transformer Using Partial Discharge Analysis. Jurnal Teknologi. 64(4): 1-5.


N. A. Othman, H. Zainuddin, A. Aman, S. A. Ghani, M. S. A. Khiar, I. S. Chairul and M. A. Talib. 2016. Investigation on the Degradation Behavior of Creepage Discharge on Pressboard Immersed in Palm Fatty Acid Ester (PFAE) Oil. Jurnal Teknologi. 78(10-3): 1-6.


Markets and Markets. 2021. Transformer Oil Market by Oil Type (Mineral (Naphthenic, Paraffinic), Silicone, Bio-based), Application (Transformer, Switchgear, Reactor), End User (Transmission & Distribution, Power Generation, Railways & Metros), and Region - Global Forecast to 2030. [Online]. Available, [Accessed 30 August 2022].

M. Duval and L. Lamarre. 2014. The Duval Pentagon-A New Complementary Tool for the Interpretation of Dissolved Gas Analysis in Transformers. IEEE Electrical Insulation Magazine. 30(6): 9-12.


J. Golarz. 2016. Understanding Dissolved Gas Analysis (DGA) Techniques and Interpretations. 2016 IEEE/PES Transmission and Distribution Conference and Exposition (T&D). 1-5.


S. Missas, M. G. Danikas and I. Liapis. 2011. Factors Affecting the Ageing of Transformer Oil in 150/20kV Transformers. 2011 IEEE International Conference on Dielectric Liquids. 1-4.


Ming Gao, Guangfan Li, Jinzhong Li and Zhigang Zhao. 2011. The Temperature Dependence of Insulation Characteristics of Transformer Oil at Low Temperatures. 2011 IEEE Power Engineering and Automation Conference. 27-30.


B. A. Thango, A. O. Akumu, L. S. Sikhosana, A. F. Nnachi and J. A. Jordaan. 2021. Preventive Maintenance of Transformer Health Index Through Stray Gassing: A Case Study. 2021 IEEE PES/IAS PowerAfrica. 1-5.


ASTM Standard D7150, 2013. 2020. Standard Test Method for the Determination of Gassing Characteristics of Insulating Liquids Under Thermal Stress. ASTM International, West Conshohocken, PA.


H. Wang, S. Ma, H. Yu, Q. Zhang and P. Wang. 2017. Study on Stray Gassing of Transformer Oil with Metal Deactivator under Condition of Coincident Electric Field and Temperature. 2017 4th International Conference on Electrical Power Equipment-Switching Technology (ICEPE-ST). 965-969.

S. Eeckhoudt, S. Autru and L. Lerat. 2017. Stray Gassing of Transformer Insulating Oils: Impact of Materials, Oxygen Content, Additives, Incubation Time and Temperature, and Its Relationship to Oxidation Stability. IEEE Electrical Insulation Magazine. 33(6): 27-32.


IEC60296. 2020. Fluids for Electrotechnical Applications-Mineral Insulating Oils for Electrical Equipment. International Standard.

Shell Lubricants. 2021. From Extending Oil Life to Powering Homes. [Online]. Available, [Accessed 09 September 2021].

IEEE Guide for the Interpretation of Gases Generated in Mineral Oil-Immersed Transformers. 2019. IEEE Std C57.104-2019 (Revision of IEEE Std C57.104-2008).1-98.


IEC 60599:2015. RLV Redline Version, Minerals Oil-filled Electrical Equipment in Service-Guidance on the Interpretation of Dissolved and Free Gases Analysis.

Reference: 296: 2006. Recent Developments on the Interpretation of Dissolved Gas Analysis in Transformers, Technical Brochures, Cigre, Task Force JTF D1.02/A2.11. 1-32.

Transformer Maintenance-Facilities Instructions, Standards, and Techniques. 2000. United States Department of the Interior Bureau of Reclamation, Washington, DC, USA. 1-87.

IEEE Standard for General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers. 2022. IEEE Std C57.12.00-2021 (Revision of IEEE Std C57.12.00-2015).1-74.

Doi: 10.1109/IEEESTD.2022.9690124.

Reference 323: 2007. Aging of Cellulose in Mineral Oil Insulated Transformers, Technical Brochures, Cigre, Task Force TF D1.01.10. 1-88.

M. Banovic, P. Ramachandran, N. Rego and P. Justiz. 2015. Significance of CO2/CO Ratio in Dissolved Gas Analysis. Transformer Magazine. 2(1): 5.




How to Cite

Yong, H. J. ., Mohd Yousof, M. F. ., Abd Rahman, R. ., Azis, N., & Talib, M. A. . (2022). THE EFFECT OF THERMAL STRESS AND MATERIALS TOWARDS STRAY GASSING FORMATION IN UNINHIBITED AND INHIBITED OIL. Jurnal Teknologi, 85(1), 33-41.



Science and Engineering