直流GIL金属微粒运动与空间电荷积聚的时空交互作用及活性抑制研究

The free or attached metal particles within DC GIL will be charged and activated under the imposed unipolar E-field, which may result in sensible charge accumulation in the main air gap space as well as on the insulator surface, causing distortion of the electric field distribution and consequently leading to deterioration or damage of the whole insulation. With quantitative analysis of the charging phenomenon, motion process and partial discharge characteristics of the metal particles, the particles charging mechanism, kinetic features and physical characterization of the particle-induced discharge are to be studied in the proposed project. Then extensive attention will be focused on the spatio-temporal interaction mechanism between metal particles and space charge under superimposed multiple fields coupling of electric, magnetic, thermal and mechanical stresses, which aims at establishment of the correlation law and synergetic effect between metal particles perturbation and interfacial charge dynamics within DC GIL, with a view to revealing the evolution mechanism of typical insulation defects induced by the coupling function of the metal particles and charge accumulation. Explorative research will be further carried out regarding the regulation theory and methodology against particles attachment and charge accumulation by nano-composite coating of the DC GIL insulator as well as the electrodes coating, and combined with the spatio-temporal features of particles motion, corresponding activity suppressing theory and methodology about harmful particles is to be put forward based on charge regulation mechanism, which is supposed to realize effective activity suppression of the metal particles as to achieve ultimate establishment of an active and synergetic defense system against particles contamination. The proposed research achievements will provide theoretical and technological basis as to greatly improve the insulation strength and operational reliability of DC GIL, which presents academic significance and application potentials in developing gas-insulated HVDC transmission lines.

直流GIL金属微粒污染物在单极性场作用下荷电并运动，可在气隙空间和绝缘子表面诱导电荷积聚，引起电场畸变进而破坏整体绝缘。本项目从金属微粒的带电现象、运动过程及局部放电特性的定量分析出发，研究金属微粒的荷电机理、动力学特性及微粒诱发放电的物理表征，然后聚焦电、磁、热、力多场耦合效应下金属微粒与空间电荷的时空交互作用机制，建立金属微粒扰动与界面电荷动力学过程的关联规律及协同效应，揭示金属微粒和电荷积聚耦合作用引起的典型绝缘缺陷演化机理；进一步探索直流GIL绝缘子纳米复合涂层以及电极涂覆对金属微粒吸附过程和电荷积聚的调控理论及方法，并结合微粒运动的时空物理特征，提出基于电荷调控机制的主动式微粒活性抑制理论与方法，实现金属微粒的有效活性抑制，构建主动式、协同型的微粒污染防御技术体系。本项目研究可为提高直流GIL绝缘强度和运行可靠性提供理论和技术基础，对发展直流管道输电具有重要的学术意义和应用价值。

直流GIL可支撑特殊地域的大容量输电需求，应用前景广阔，但其绝缘设计面临金属微粒与电荷积聚两大核心问题，严重影响气-固绝缘电气强度。为提升直流GIL绝缘设计水平和运行可靠性，本项目旨在研究揭示多场耦合环境下直流GIL金属微粒和空间、界面电荷对气-固复合绝缘系统的协同劣化机制，并基于此建立直流GIL复合绝缘优化设计和金属微粒协同调控的理论与方法。.（1）实验获得了金属微粒与绝缘纤维的运动特性及分布规律，揭示了微粒飞萤现象的发生与演化机制，提出了飞萤运动的临界起始判据；采用自主研制的多自由度表面电位测量平台与表面视在电荷反演算法，获得了温度分布和微粒附着对表面电荷积聚特性的影响规律；建立了金属微粒附着过程的动力学模型，提出了绝缘子表面电荷对微粒吸附过程的作用机制。.（2）揭示了表面附着金属微粒引发的绝缘子沿面闪络机制，建立了自由微粒诱导气隙击穿的发展模型，获得了金属微粒与绝缘纤维协同诱发气隙击穿的物理机制；提出了基于放电特征检测的金属微粒危险程度评估方法，实现了微粒尺寸与运动模式的有效识别。.（3）建立了基于分子模拟的绝缘子涂层材料介电与理化性能预测方法，实现了涂层材料纳米掺杂方案的优化；设计制备了兼具抑制粉尘吸附效能与抗粘黏性能的纳米涂层，同时实现对界面电荷积聚/消散特性的有效调控；结合实验测试与仿真分析，揭示了涂层电损伤与热裂解的理化机制；提出了界面绝缘的增强设计方法，有效提升了直流盆式绝缘子与三支柱绝缘子的沿面绝缘强度。.（4）建立了电极覆膜时金属微粒的运动荷电模型，提出了电极覆膜材料的遴选原则，改性设计并制备了高性能聚酰亚胺覆膜材料，显著提升了对微粒吸附运动的抑制效果；提出了用于直流GIL的提上式微粒陷阱与楔形陷阱几何结构，并基于三维粒子可视化追踪仿真，建立了微粒陷阱关键参数的优化设计方法；融合覆膜式微粒陷阱、驱赶电极和老练程序，提出了金属微粒的主动式协同抑制方案。.基于上述研究，发表学术研究论文73篇（其中SCI收录34篇、EI收录29篇），授权国家专利8件，培养博士研究生7名、硕士研究生19名，主办学术会议3次，受邀在国际国内会议做主旨报告6个。研究成果可应用于不同电压等级的交直流输电管道绝缘设计，为电荷积聚调控和微粒污染治理奠定了理论基础与方法支撑。