Jihan Fadhilah, Rahman Azis Prasojo, Sriyono
This paper presents a detailed technical evaluation and standards-based assessment of natural and synthetic ester oils as alternative insulating fluids to conventional mineral oil in Indonesian power transformers. Due to growing environmental awareness and sustainability concerns, ester oils - both natural and synthetic - have emerged as potential insulating fluids with distinct advantages such as biodegradability, higher flash points, and improved fire safety compared to traditional mineral oils. This study compares these oils based on relevant international standards (IEEE and IEC), emphasizing critical parameters including dielectric strength, moisture absorption capability, oxidation stability, and thermal performance. Particular attention is given to acceptance criteria for new oils and pre-energization conditions specific to transformer operation in the Indonesian tropical climate. Findings indicate that ester-based oils show significant technical and environmental benefits but require careful handling related to their viscosity, oxidation stability, and compatibility with existing mineral oil systems. This comparative evaluation provides critical insights for stakeholders and utilities in Indonesia seeking sustainable and reliable alternatives to conventional transformer insulating oils. © 2025 IEEE.
PLN Research Institute, Compliance, and Integrated Management System, Jakarta, Indonesia; Politeknik Negeri Malang, Department of Electrical Engineering, Malang, Indonesia; PLN Research Institute, Research and Technology of Transmission and Distribution system, Jakarta, Indonesia