Abstract Surface charging phenomena on DC GIL spacers is a complicated process affected by lots of factors, among which surface conductivity is an important dielectrics parameter. In this study, experimental and theoretical research are carried out to investigate the effects of non-uniform surface conductivity on surface charge accumulation behaviours of downsized HVDC GIL spacers. A SiC/epoxy layer is partially coated on alumina/epoxy spacers to form a non-uniform surface conductivity. The coating manners include sector-shaped coating and ring-shaped coating. The accumulated surface charges show a rising first and then decreasing trend with the increase of SiC contents in coated area. When surface conductivity is high enough, there is almost no charge accumulation. Bipolar charges, which are generally observed on raw alumina/epoxy spacers, are found to be preferable to accumulate at interface region between high and low surface conductivity. The orientation of bipolar charges is determined by the distribution of inhomogeneous surface conductivity. The formation mechanism of bipolar charges at the interface is revealed based on the experiment and simulation results. Besides, a uniform surface conductivity contributes to suppressing randomly distributed surface charges including bipolar charges, which can provide guidance for designing and optimizing highly reliable and stable HVDC GIL.

中文翻译：

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一种理解具有非均匀导电性的小型高压直流 GIL 垫片表面充电现象的新视角

摘要 DC GIL 垫片的表面充电现象是一个复杂的过程，受多种因素影响，其中表面电导率是一个重要的介电参数。在本研究中，开展了实验和理论研究，以研究非均匀表面电导率对缩小尺寸的 HVDC GIL 间隔物表面电荷积累行为的影响。碳化硅/环氧树脂层部分涂覆在氧化铝/环氧树脂隔离物上，以形成不均匀的表面导电性。涂覆方式包括扇形涂覆和环形涂覆。累积表面电荷随着涂覆区SiC含量的增加呈现先上升后下降的趋势。当表面电导率足够高时，几乎没有电荷积累。双极电荷，通常在未加工的氧化铝/环氧树脂垫片上观察到，发现最好在高和低表面电导率之间的界面区域积聚。双极电荷的取向由不均匀表面电导率的分布决定。基于实验和模拟结果揭示了界面处双极电荷的形成机制。此外，均匀的表面电导率有助于抑制随机分布的表面电荷，包括双极电荷，这可以为设计和优化高度可靠和稳定的 HVDC GIL 提供指导。基于实验和模拟结果揭示了界面处双极电荷的形成机制。此外，均匀的表面电导率有助于抑制随机分布的表面电荷，包括双极电荷，这可以为设计和优化高度可靠和稳定的 HVDC GIL 提供指导。基于实验和模拟结果揭示了界面处双极性电荷的形成机制。此外，均匀的表面电导率有助于抑制随机分布的表面电荷，包括双极电荷，这可以为设计和优化高度可靠和稳定的 HVDC GIL 提供指导。