Study On Movement Characteristics And Suppression Of Metal Particle Dust In AC GIL

Gas insulated transmission lines(GIL)have a broad application in the field of highvoltage transmission,and the metal particle contamination in GIL has a great threat to its safe and stable operation.According to on-site operating experience,insulation failures caused by metal particulate dust(MPD)occur frequently.And it is currently difficult to provide targeted suppression methods due to insufficient understanding of the MPD movement characteristic under AC voltage.To address the above issues,this paper conducted a study on the motion characteristics of metal particulate dust under alternating current.Based on this,an optimization method for particle trap parameters was proposed,and a new method for particle dust adhesion inhibition was proposed.(1)The motion characteristics of metal particles in front of the trap were studied.The dynamic model and motion model of metal particles in front of the trap under AC voltage are established and simulation analysis is conducted.The simulation results show that under AC voltage,the movement of metal particles is strong in randomness and low in activity;The particles move away from the trap in a fluctuating upward downward motion trend.Among the particles moving towards the trap,some of them stay in front of the trap due to the influence of the low field strength region in front of the trap,while some of them fall into the trap from above;An experimental platform for particle motion was built to verify the accuracy of the simulation results.(2)The optimization method of particle trap parameters under AC voltage is studied.Based on the aforementioned particle motion model,a particle dust motion model in front of the trap is established considering the Coulomb force between particles,and a simulation calculation method for the trap capture rate is given.The research shows that among the structural parameters of the particle trap,the thickness and height have a significant impact on the trap capture effect,and as the thickness/height increases,the capture of the particle trap first rises and then decreases;Based on the whale optimization algorithm,the trap parameters are optimized,and the feasibility of the optimization method is verified through experiments;Under experimental conditions,the optimized trap parameters are:slot width of 4mm,slot pitch of 3mm,thickness of 6mm,and height of 4mm.The trap capture rate can reach 51%.(3)The suppression method of metal particle dust adhesion on the surface of insulators was studied.A suppression method using polytetrafluoroethylene(PTFE)interface instead of epoxy resin(ER)interface was proposed,and the adhesion characteristics of metal particle dust at the two interfaces were analyzed.Due to the small adhesion work of PTFE insulator material,the adhesion force of PTFE insulator material is smaller than that of ER insulator material;Furthermore,the influence of metal particles on the surface flashover performance of the two materials was studied.The results showed that the voltage of the insulator surface flashover performance of the two materials was close,with a difference of no more than 3%;Finally,an implementation scheme is proposed,which is to fabricate a PTFE insulator protective shell to replace the epoxy resin surface.The feasibility of this method is verified through experiments.