Design and Fabrication of ε -FGM Spacers for Efficient Expulsion of Metal Particles

This study investigates the impact of gradient number and metal particle radius on the electric field regulation and metal particle expulsion characteristics of permittivity functionally graded material (ε-FGM) insulators for gas-insulated switchgears (GIS). The electric field distributions and particle movement characteristics are investigated by simulation, with the gradient layers of the εn-FGM insulators set to 4, 6, 8, and 10, respectively. The ε4-FGM insulator with 4 gradient layers exhibits the lowest electric field intensity at the triple junction, which is 32% lower than that of the uniform insulator. Additionally, the axial electric field component is the highest, with its peak value 78% higher than that of other εn-FGM insulators, thereby offering the best performance in expelling metal particles. The expulsion effect of the εn-FGM insulators on metal particles is diminished when the particle radius is excessively large or small, with the most effective particle size ranging from 100 and 250 μm. Moreover, both a scaled ε4-FGM sample and a full-sized ε-FGM insulator for 110 kV GIS are prepared for experimental tests. As the metal particle radius increases, the axial movement speed of particles at the concave side of the ε4-FGM insulator decreases, while the gap between the insulator surface and particles shows a growth trend. The full-sized ε-FGM insulator, with a continuous permittivity gradient distribution, can effectively repel metal particles in its vicinity, even in the presence of multiple particles. This work presents a novel method for mitigating metal particle contamination in GIS, which improves grid safety, reduces maintenance costs, and promotes sustainable and intelligent high-voltage technologies with significant theoretical and engineering value.