Wang Yang, Yan Wenchao, Cui Kunqi, Cheng Chuanhui, Ren Yuanyang, Wu Kai
School of Electronics and Information, Xi'an Polytechnic University, Xi'an 710048, China.
Xi'an Key Laboratory of Interconnected Sensing and Intelligent Diagnosis for Electrical Equipment, Xi'an Polytechnic University, Xi'an 710048, China.
Molecules. 2024 Sep 22;29(18):4500. doi: 10.3390/molecules29184500.
Despite the fact that doping nanoparticles into insulating transformer oil has proven to be an effective method of enhancing its dielectric and electrical properties, it remains unclear how different types and surface conditions of nanoparticles may affect their dielectric and electrical properties. Therefore, the effect of doping various types of BN nanoparticles (nanosphere, nanotube, and nanosheet) in insulating mineral oil (MO) on the diffusion properties of water molecules and electrical properties across the BN/MO interface was investigated using molecular dynamics (MD) and Density Functional Theory (DFT) simulations. Our results show that different surface morphology and grafted functional groups in different types of BN nanoparticles have a significant impact both on the water diffusion behavior and the interfacial potential barrier across the interface between BN and MO. In the MO system directly doped by BN nanospheres, water diffusion behavior is not significantly restricted. However, grafting -NH polar groups onto the BN nanoparticle surface may significantly limit the diffusion behavior of water due to the strong attraction between the -NH polar groups and water molecules; the most significant effect is with nanospheres, followed by nanotubes and nanosheets. In terms of electrical properties across the interface between BN and MO, the h-BN surface (derived from BN nanosheets and nanotubes) acts as a trap for electrons in MO (-0.59 eV), while the c-BN surface (derived from BN nanospheres) acts as a potential barrier for electrons in MO (1.45 eV), and it is noteworthy that the presence of water molecules near the interface between BN and MO has little impact on the potential barriers. Advancing a fundamental understanding of the electrical and water diffusion properties of MO in correlation with the surface morphology of different types of nanoparticles is key to improving the insulation properties of oil-impregnated power transformers.
尽管将纳米颗粒掺杂到绝缘变压器油中已被证明是增强其介电和电气性能的有效方法，但目前尚不清楚不同类型和表面条件的纳米颗粒如何影响其介电和电气性能。因此，使用分子动力学（MD）和密度泛函理论（DFT）模拟研究了在绝缘矿物油（MO）中掺杂各种类型的BN纳米颗粒（纳米球、纳米管和纳米片）对水分子扩散特性和跨BN/MO界面的电气性能的影响。我们的结果表明，不同类型的BN纳米颗粒中不同的表面形态和接枝官能团对水的扩散行为以及BN与MO界面间的界面势垒均有显著影响。在直接由BN纳米球掺杂的MO系统中，水的扩散行为没有受到明显限制。然而，由于-NH极性基团与水分子之间的强烈吸引力，在BN纳米颗粒表面接枝-NH极性基团可能会显著限制水的扩散行为；影响最显著的是纳米球，其次是纳米管和纳米片。就BN与MO界面间的电气性能而言，h-BN表面（源自BN纳米片和纳米管）在MO中充当电子陷阱（-0.59 eV），而c-BN表面（源自BN纳米球）在MO中充当电子的势垒（1.45 eV），值得注意的是，BN与MO界面附近水分子的存在对势垒影响很小。深入了解MO的电气和水扩散特性与不同类型纳米颗粒表面形态之间的关系是提高油浸式电力变压器绝缘性能的关键。
