Hydrogen Gas (H2) Generation in Hermetically Sealed Oil Filled Power Transformers: Evaluating HSE Risk, Addressing Challenges & Deploying Mitigation Measures

This paper investigates the abnormal increase in hydrogen (H2) levels observed during pre-energization Dissolved Gas Analysis (DGA) of oil (MIDEL-7131) in four hermetically sealed Power Transformers at an ADNOC Offshore facility. These transformers have been stored in a warehouse for over 18 months prior to installation. DGA testing diagnosed H2 concentrations exceeded allowable limit of 100 ppm, as defined by IEEE C57.104 & IEC 60599. Recorded H2 levels ranged from 323ppm to 1141ppm, indicating significant potential risk to HSE, operational integrity, business continuity, and loss of production. An integrated approach has been developed through discussions with key stakeholders, including the Original Equipment Manufacturer (OEM), EPC Contractor and Consultants. This collaborative effort led to root cause analyses and the identification of the most efficient and cost-effective methods for mitigating hydrogen accumulation in the newly manufactured and ready for installation transformers. Furthermore, the proposed mitigation measures both short term and long term are discussed, including degassing and dehydration of oil. With a focus on addressing challenges and proposing effective mitigation strategies, this paper provides actionable insights for practicing engineers. The paper concludes with recommendations for long-term monitoring and preventive maintenance (PM) practices and enhancing the reliability and safety of electrical systems in Oil & Gas industry. Future work will focus on monitoring the effectiveness of the implemented short-term mitigation measures and exploring additional strategies for further risk reduction as needed. The study also explores emerging technologies including Artificial Intelligence (AI) for managing hydrogen- related risks contributing to enhance transformer reliability, extend equipment lifecycle and safety in high- demand operational environments; ultimately helping to prevent catastrophic failures.