Gas Production Characteristics and Molecular Mechanism of Mixed Insulating Oil Containing Ethyl Laurate under Arc Discharge

Mixed insulating oils can complement the performance advantages of individual oils, presenting significant potential for practical applications. This paper investigates the gas production characteristics of mixed insulating oils containing ethyl laurate. Gas production tests were conducted using electrothermal cracking to examine the behavior of mineral oil, ethyl laurate, and mixed insulating oil under arc discharge conditions. Using the ReaxFF reaction force field and molecular dynamics theory, the gas production characteristics and molecular mechanisms inhibiting gas production in mixed insulating oils containing ethyl laurate were analyzed. The results indicate that ethyl laurate exhibits relatively low molecular stability. At lower temperatures, ethyl laurate cracks at a faster rate and produces more gas molecules compared to mineral oil. As temperature increases, the cracking of mineral oil accelerates, leading to higher gas production. However, the pyrolysis reaction pathway in ethyl laurate becomes more complex, slowing the subsequent gas production rate. Consequently, at higher temperatures, ethyl laurate generates fewer gas molecules. Additionally, ethyl laurate has a higher free volume fraction than mineral oil, enhancing gas diffusion and solubility within the oil. Thus, while mineral oil cracking generates fewer gas molecules at lower temperatures, the total gas volume collected is greater compared to that of ethyl laurate and mixed insulating oils. Ethyl laurate inhibits gas release in insulating oils during electrothermal cracking by enhancing gas solubility in the oil. This paper offers a novel approach for controlling gas production in insulating oils under arc fault conditions.