Trap Parameters Optimization Based on Metal Particle Dynamic Simulation Method

Abstract

Insulation failure usually occurs in AC gas-insulated transmission (AC GIL) in field operation, in which the primary cause is the charged motion of metal particles in the electric filed. At present, the particle inhibition method applied is to design particle traps on the inner wall of the GIL shell. However, due to the large randomness of the charged motion for metallic particles and the limitations of field test methods, a particle trap has not yet been designed from the perspective of particle trapping effectiveness. In this paper, firstly, referring to the size of a running 252 kV AC GIL, a 1:1 scaled 3-D similarity simulation model is established to obtain the dynamic characteristics of particles with different sizes under the operating voltage level. This model can form symmetry between the real equipment, and its simulated simulation trajectory can achieve symmetry with the actual one. Secondly, an experimental platform that can easily capture the motion of the particles is set up to experimentally verify the symmetry between the field operating equipment and the simulation model. Finally, the particle traps are set on both sides of the concave and convex surface of the basin insulator, and an optimization scheme for the design of the particle trap is proposed from three aspects: the electric field regulation of the trap, the captured probability of particles, and the trap location. The proposed research shows that, with respect to the motion characteristics of the particles, this paper selects circular hole-shaped trap and its thickness, slot spacing, and slot width are 10 mm, 6 mm, and 8 mm, respectively. When the traps are arranged, one at the bottom of the shell at 70 mm and 80 mm from each side of the concave and convex insulator, the capture probability of the traps on both sides can be as high as 78% and 70%, respectively. Therefore, the analysis and optimization method in this paper has important reference value according to similarity concepts for optimizing particle traps in AC GIL at a certain voltage level.