Electrodes Coordination in Suppressing Metal Particle in DC Gas-insulated Asset: Fundamental Research

Under the direct current electric field, the metal particles inside GIS/GIL exhibit reciprocating bouncing and firefly movements, which pose a relatively large hazard to the insulation system. This paper explores the roles slope electrode and ground electrode coating play on restraining the of metal particle motion. The results show that in the case of the slope electrode, the movement of metal particles is affected by the reflection angle and the electric field gradient force. Among them, the electrode reflection angle drive is dominant when the spherical metal particles move through the insulating gas gap, while the electric field gradient force drive is dominant when the linear metal particles fly; the coating has a significant effect on increasing the take-off voltage of spherical metal particles, but the effect of increasing the take-off voltage of linear metal particles depends on the contact mode between the particles and the coated electrode when they are stationary. Approximately 30% of the linear metal particles can be suppressed. The research results can provide a reference for the comprehensive suppression of metal particles in DC GIS/GIL.