Study on Size of Particle Collector to Restrain Interface Defect of GIL

Gas insulated transmission line (GIL) has been widely used in the field of high voltage transmission because of its high reliability, large transmission capacity and friendly environment. As a key component of GIL, three post insulator will have stress concentration on the interface of low-voltage end insert, SF
₆
gas and insulator during the curing process, which will lead to interface peeling, interface defects and endanger the safe operation of GIL. It is found that the shielding area formed by the low-voltage end insert and the particle collector in the low electric field area at the end of the leg has a good shielding effect on this kind of defect. So the particle collector is usually used to shield this defect in engineering. In this paper, 1100kV three post insulator is taken as the research object. By using the COMSOL simulation, five particle collector width values, six particle collector thickness values, six insert depth values and six defect depth values are selected. The shielding effect of particle collector width, thickness and low-voltage end insert size on the harmful electric field in the defect is studied, and the influence of shielding area on the shielding effect of different depth defects is analyzed. The results show that in a certain size range, increasing the width and thickness of the particle collector can significantly improve the shielding effect, while the increase of the depth of the low-pressure end insert can inhibit the overall electric field strength in the defect, and the shielding effect of the insert and the particle collector decreases significantly with the increase of the defect depth. Finally, by comparing the electric field intensity values of defects under different conditions, the reasonable size selection of particle collector and metal insert of this GIL device is given.