Research on the Dynamic Capture by Particle Trap in 1100 kV Gas Insulated Transmission Line for Metal Particles

The 1100 kV gas insulated transmission line (GIL) is applied to the Sutong high-voltage transmission project in China, and its rated voltage level is the highest in the world. In order to ensure the insulation reliability, when designing the product, a particle trap is arranged near the insulator to capture nearby metal particles and reduce the chance of flashover on the surface of the insulator. The internal insulation structure and geometric size of GIL determine the potential gradient distribution. The particle motion is affected by its own gravity, coulomb force, electric field gradient force, gas resistance and friction. The motion law is complicated and difficult to measure. In this paper, the numerical modeling method is used to establish the motion model of metal particles near the trap of 1100 kV GIL. The trajectories of particles for different sizes at different voltages and initial positions are obtained. By analyzing the law of particle motion, the GIL product pre-conditioning test program is guided, and the different sizes of particles that may exist in the GIL are classified and captured by the step-by-step voltage applying voltage method, thereby increasing the trapping effect of the particle trap and improving the insulation reliability of on-site operation in the product. Finally, the feasibility of the preconditioning test scheme design using this numerical method is verified by the particle motion observed by the camera.