高耐电性能3D打印介电功能梯度绝缘的关键基础研究

For a long time, the weak dielectric strength of insulators due to local electric field distortion is a common problem in high voltage power equipment, and the limitations of conventional solutions such as structural optimization and material modification are becoming more and more prominent. In this project, based on the dielectric functionally graded material (d-FGM) concept, the solid insulation with non-uniform permittivity distribution is built. The spatial distribution of permittivity is adjusted to optimize the electric field distribution as well as significantly improve the dielectric strength. This project is organized in these aspects: Firstly, optimization methods for the spatial distribution of permittivity will be investigated. Secondly, permittivity-adjustable and 3D-printing-applicable composite insulating material will be established. Thirdly, novel 3D printing technique for graded material properties would be explored. Finally, performance evaluation methods for d-FGM insulation would be syudied based on non-destructive detection approach of permittivity distribution of graded insulation, as well as the influence of permittivity distribution on dielectric strength. By performing this project, we can realize the integration of optimization design, material property adjustment and 3D-printing fabrication for d-FGM insulator, thus providing novel approach for the improvement of electrical performance and miniaturization of electrical power equipment.

长期以来，因局部电场畸变而导致的绝缘子耐电性能薄弱是高压电力设备中普遍存在的难题，传统结构优化及材料改性方法局限性越发突出。本项目基于介电功能梯度(Dielectric Functionally Graded Material, d-FGM)理念，构建介电常数空间非均匀分布的d-FGM绝缘结构，通过调控介电常数空间分布以优化电场分布、显著提升耐电性能。具体围绕d-FGM的优化设计、材料制备、3D打印和性能评价等方面开展深入研究：提出d-FGM绝缘子介电常数分布的优化设计方法；建立介电常数可调、可3D打印的复合绝缘材料体系；依托3D打印探索d-FGM的精确成形工艺；研究梯度绝缘介电常数分布的无损检测技术，探索d-FGM绝缘子介电特性空间分布对其耐电性能的影响规律。通过本项目研究，实现d-FGM绝缘子概念设计、材料参数调控和3D打印成形的一体化，为绝缘耐电性能提升和设备小型化提供新的技术途径。

为解决局部电场集中导致的固体绝缘部件放电破坏难题，构建介电常数/电导率呈现空间非均匀分布的介电功能梯度(Dielectric Functionally Graded Material, d-FGM)绝缘子，围绕固体绝缘的介电特性空间分布对其耐电特性的影响规律与调控机制这一关键科学问题开展研究，取得了以下重要成果：.1）建立了d-FGM绝缘件拓扑设计方法。提出了适用于逐层式和逐点式d-FGM优化的缩减迭代和拓扑优化算法，具有收敛性好、数值稳定、效率高的优势；开展了圆台、盆式、支柱等典型绝缘结构介电常数/电导率的空间分布进行设计，实现了电场均匀度的显著提升。.2）构建了d-FGM绝缘件3D打印材料体系。优选出熔融堆积（FDM）和立体光固化（SLA）两种工艺作为热塑性和热固性d-FGM的3D打印实现方法；采用基体聚合物/无机填料复合的方法构建上述工艺的打印材料体系，合成了耐温性能良好的SLA工艺用环氧丙烯酸树脂；厘清了填料颗粒关键特征与材料介电特性与工艺兼容性的关联性，挖掘了其中的调控机制；在此基础上，构建了介电常数的单指数模型预测方法，为3D打印提供理论指导。.3）研发了d-FGM绝缘件3D打印设备。开发了适用于热塑性材料的主动混合-熔融堆积工艺和适用于热固性材料的光固化直写-约束牺牲层工艺，完成了离散/连续d-FGM样件精准制备；针对大尺寸d-FGM绝缘件，提出了3D打印-真空浇注“两步”制备方法，满足10kV、126kV全尺寸d-FGM绝缘子的需求。.4）确立了d-FGM绝缘件综合性能评价体系。实验验证了d-FGM沿面耐电强度提升效果，揭示了SF6和真空氛围中沿面闪络电压与介电梯度分布的关联机制。利用X射线断层扫描与电容层析检测技术，实现了d-FGM制造缺陷与介电常数分布的快速、无损检测；完成了10kV热塑性/热固性开关柜支柱以及126kV热固性盘式GIS绝缘子的制造，并实现了10kV热固性支柱的挂网试运行。.项目组形成了融合d-FGM绝缘子概念设计、材料调控、3D打印与特性评估的一体化技术体系，获得的介电功能梯度绝缘部件通过了第三方性能试验，并在现场开关柜中成功进行了挂网试运行。项目成果不仅在介电功能梯度绝缘的科学研究方面实现了国际引领，也为绝缘部件的可靠性提高与小型化发展提供了新的技术途径，并为现场应用奠定了良好基础。