A multi-physics simulation model of the tri-post insulator in ±800 kV GIL laid horizontally is established to study the effects of gas convection on surface charges and electric field distribution. Results show that gas density together with the dielectric strength around the upper post is reduced over 11% under gas convection generated by the load current. The larger temperature gradient (29 K) along the lower post accelerates more surface charge injection through insulator buck conduction and distorts the electric field around the bottom of the lower post, which is 19.4% higher than that around the bottom of the upper post. The insulation performance of SF 6 /N 2 filled GIL has the most striking spatial distribution characteristics compared with the insulation performance of SF 6 and C 4 F 7 N/CO 2 . Though the flashover voltage is improved with high gas pressure, the flashover is most likely triggered near the lower post of the insulator according to the stream theory. It is hoped that this study can contribute to a useful guide for the design and manufacture of DC-GIL.

中文翻译：

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气体对流影响 ±800 kV GIL 中三柱绝缘子周围的表面电荷和电场分布

为了研究气体对流对表面电荷和电场分布的影响，建立了±800 kV GIL水平铺设三柱绝缘子的多物理场仿真模型。结果表明，在负载电流产生的气体对流下，气体密度和上柱周围的介电强度降低了 11% 以上。沿着下柱的较大温度梯度 (29 K) 通过绝缘体降压传导加速了更多的表面电荷注入，并使下柱底部周围的电场扭曲，比上柱底部周围的电场高 19.4%。SF的绝缘性能 6 /N 2 填充GIL与SF的保温性能相比具有最显着的空间分布特征 6 和 C 4 F 7 一氧化碳/一氧化碳 2 . 虽然通过高气压提高了闪络电压，但根据流理论，闪络最有可能在绝缘子下柱附近触发。希望这项研究能够为 DC-GIL 的设计和制造提供有用的指导。