直流气体绝缘输电线路的绝缘设计

气体绝缘输电线路(gas insulated transmission line，GIL)与架空线路相似但占地空间小、损耗低，在高压直流输电和特高压直流输电领域具有较大的应用空间。通过分析表面电荷和金属导电微粒对绝缘子沿面放电的影响，指出了绝缘子表面电荷积聚和自由金属导电微粒附着是降低直流GIL绝缘性能的重要原因。采用了使电场分布合理的方法，即半圆锥形盆式绝缘子的优化和表面电阻率阶梯分布的覆膜。设计了包括电极覆膜、微粒陷阱、驱赶电极和屏蔽环的直流GIL的绝缘结构。

Insulation Design of Gas Insulated HVDC Transmission Line

The electrical specification of gas insulated transmission line (GIL) is similar to overhead line and the former possesses many advantages such as less land occupation, low-loss etc., it will be extensively applied in the field of high and ultra-high voltage power transmission. By means of analyzing the impact of surface charge accumulation and free metallic conducting particles on surface discharge of insulators, it is pointed out the that the surface charge accumulation and the adhesion of free metallic conducting particle are key reasons causing insulation performance deterioration of HVDC GIL. To ameliorate this condition, the methods that make the distribution of electric field around the insulator more reasonable are adopted, i.e., the optimization of semi-conical disc insulator and film coating to make the distribution of surface resistivity step-shaped. The insulation structure for HVDC GIL, including film-coated electrode, particle trap, particle driving electrode and field-well ring, which can restrict the movement of free metallic conducting particle is designed.