Jiang Yizhou, Huang Zhengyong, Li Jian, Wang Feipeng, Zhao Chen
State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing 400044, China.
J Chem Phys. 2025 Apr 28;162(16). doi: 10.1063/5.0260009.
Natural ester (NE) insulating oil is increasingly recognized as an ideal insulating medium for power equipment, attributed to its high ignition point and biodegradability. As power systems advance to higher voltage levels, enhancing the dielectric properties of natural ester insulating oil has emerged as a key research focus. While nanoparticles enhance dielectric properties, their limited dispersion stability restricts practical applications. Liquid crystals, a novel functional modification material compatible with insulating oil, provide a new approach for modifying NE due to their unique mobility and anisotropy. Experimental results indicate that incorporating liquid crystal molecules at a 0.3% mass fraction enhances the AC breakdown strength of natural ester insulating oil by 16.7%. By combining molecular dynamics and density functional theory principles, the microscopic mechanism of liquid crystal modification was analyzed by modeling oil molecules before and after modification. The study found that liquid crystal molecules significantly reduce the system's free volume and hinder water molecule diffusion through hydrogen bonding. Furthermore, the high electron affinity of liquid crystal molecules reduces carrier mobility by capturing free electrons, thereby effectively suppressing partial discharges and electrochemical reactions. This study investigates the modification mechanism of a novel functional material on the dielectric properties of natural ester insulating oil from a microscopic perspective.
天然酯（NE）绝缘油因其高闪点和生物降解性，日益被认为是电力设备的理想绝缘介质。随着电力系统向更高电压等级发展，提高天然酯绝缘油的介电性能已成为关键研究重点。虽然纳米颗粒可增强介电性能，但其有限的分散稳定性限制了实际应用。液晶作为一种与绝缘油兼容的新型功能改性材料，因其独特的流动性和各向异性，为改性天然酯提供了新途径。实验结果表明，以0.3%的质量分数掺入液晶分子可使天然酯绝缘油的交流击穿强度提高16.7%。通过结合分子动力学和密度泛函理论原理，对改性前后的油分子进行建模，分析了液晶改性的微观机理。研究发现，液晶分子显著降低了体系的自由体积，并通过氢键阻碍水分子扩散。此外，液晶分子的高电子亲和力通过捕获自由电子降低了载流子迁移率，从而有效抑制局部放电和电化学反应。本研究从微观角度探讨了一种新型功能材料对天然酯绝缘油介电性能的改性机理。
