| Gas insulated metal enclosed transmission line(GIL)is of great significance for solving the problem of power transmission in areas where China's power transmission corridors are tight and high-altitude and large-drop areas.During the operation of GIL,it is inevitable that metal particles will appear in GIL due to mechanical collision,equipment vibration and other reasons.On the one hand,the presence of particles makes the local electric field stronger,and the device withstand voltage drops.On the other hand,the particles are induced to be charged in the electric field and are moved by the electric field force,which is the source of the insulation performance of the particle-degraded GIL system.Therefore,this paper studies the movement of spherical metal particles in the GIL uneven field under DC voltage,and discusses the factors affecting the movement of metal particles.The electric field distortion on the surface of particles under the condition of coating film was analyzed to provide theoretical guidance for harmless measures of particles.Firstly,a wedge-shaped plate electrode system is built to simulate the uneven field existing in the GIL.The theoretical analysis of the force of the spherical metal particles is carried out,and the motion model of the particle is established to prepare for the simulation of the particle motion trajectory in the GIL uneven field.The simulation study of particle motion in wedge-shaped plate electrodes establishes a three-dimensional simulation calculation model of particle motion,simulates the trajectory of spherical metal particles under the action of DC voltage applied to the wedge-shaped flat high-voltage electrode,and studies the factors affecting the particle motion trajectory.The electric field distortion of the surface of metal particles under membrane conditions was studied.The simulation model of the particles on the surface of the bare electrode and the surface of the low-pressure electrode was established.The mechanism of the influence of the film on the electric field force of the metal particles was studied.The effect of film thickness and material on the electric field distribution on the surface of the particles was investigated.The research shows that in the slightly uneven electric field,the particle motion is divided into the horizontal sliding phase,the take-off phase and the collision phase.When the initial position of the particle,the applied DC voltage amplitude,the particle size and the material change,the motion trajectory will change and can be utilized.The characteristics of particle motion law,reasonable arrangement of particle traps,select the most favorable structure.Particle motion will cause distortion of the surrounding electric field,and the overall electric field distribution inside the cavity will have little effect.The metal particles are located on the surface of the bare electrode,and the maximum field strength appears at the top of the particle,and the particles are subjected to an upward electric field force.When the particles are located on the surface of the low-voltage electrode-coating,the maximum field strength appears between the metal particles and the PET film.There are two cases of the direction of the electric field force,and the downward direction of the electric field force may be a factor for the increase of the take-off field strength of the particles under the low-voltage electrode-coating.Under film conditions.The thickness and material of the film will affect the distribution of electric field on the surface of metal particles,which can not be ignored.When selecting the film,attention should be paid to the material and thickness of the film,which will affect the film covering effect. |
PDF Full Text Request