COMPARATIVE STUDY OF THE DIELECTRIC CHARACTERISTICS OF MINERAL, GAS-TO-LIQUID, AND SYNTHETIC ESTER TRANSFORMER OILS AFTER THERMAL AGING

• Main Author: Kurniawan, Mashudan
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86835
• Institution: Institut Teknologi Bandung

Insulating oil is a critical component in transformers, serving to support insulation and cooling functions. This study aims to evaluate the chemical, physical, and electrical characteristics of three types of insulating oils—mineral oil, Gas-to- Liquid (GTL) oil, and synthetic ester oil—after undergoing thermal aging processes. The study was conducted to determine the reliability and performance of each oil in maintaining transformer functionality under long-term operational conditions. The evaluation of insulating oils included measurements of color scale, acidity, water content, breakdown voltage (BDV), relative permittivity, resistivity, dissipation factor (tan ?), and dissolved gas analysis (DGA). In addition, tests on oil-immersed paper insulation involved measuring tensile strength and the degree of polymerization. The oil samples were tested in their new condition and after undergoing thermal aging at varying temperatures of 100°C, 125°C, and 150°C, as well as aging durations of 168 hours, 504 hours, and 840 hours to simulate longterm operational conditions. The results indicate that synthetic ester oil is recommended for applications requiring long-term stability and environmental considerations, while GTL oil serves as an economical alternative with better stability compared to mineral oil. This study provides significant contributions to supporting the selection of optimal insulating oils to enhance transformer efficiency and reliability.z