±800 kV特高压直流GIL关键技术研究

为了提高特高压直流输电线路走廊选择的灵活性，研究可以替代部分架空输电线路的直流气体绝缘金属封闭输电线路(gas insulated metal enclosed transmission line，GIL)具有重要意义。提出了在进行直流GIL绝缘子相关试验时，以带绝缘子的圆柱平板电极替代带绝缘子的同轴圆柱电极的试验方法。结合国外小尺寸电极试验结果，采用麦夸特法拟合得到了考虑表面粗糙度的同轴圆柱电极SF6气体间隙下临界击穿场强估算公式。设计了包含微粒陷阱、微粒驱赶电极和屏蔽环的直流GIL电极结构，并对此进行了电场分布的仿真，结果表明此结构具有抑制金属导电微粒运动的作用。

Study on Key Technology of ±800 kV UHVDC GIL

In order to improve the flexibility of transmission corridor right of way in ultra-high voltage DC system, it is necessary to study DC gas insulated metal enclosed transmission line (GIL) which can replace sections of overhead lines. Based on international test results of small-scale electrode and considering the surface roughness, the equation which can be used for estimating the critical breakdown field is deduced by using Levenberg-Marquart method. During these tests related insulator of DC GIL, the test method using the cylinder-flat electrode instead of the coaxial cylinder electrode, is presented. The DC GIL electrode which includes particle trap, particle driver and field-well ring is designed. Electric field distribution of this electrode is also emulated. The results indicate the triple structure can limit the activity of the metal conducting particle.