直流应力下主动式微粒抑制方法的动态配合研究

Research on Dynamic Coordination of Active Particles Suppression Methods under DC Stress

直流气体绝缘输电线路(GIL)中自由金属微粒的活性较之交流GIL中更为活跃,对直流GIL的技术发展以及应用带来了严峻的挑战。目前,将各种抑制微粒手段进行主动式动态配合设计是未来发展的趋势。该文搭建直流GIL金属微粒主动式抑制的动态配合实验平台,并结合有限元仿真,从陷阱捕获率的角度优化了驱赶电极与陷阱间的位置配合;同时提出直流老练优化程序,最终获得主动式微粒抑制的动态配合有效方案。研究结果表明,当驱赶电极与陷阱间的距离为18 mm时,陷阱捕获率可高达70%;该文优化后的直流老练程序较传统程序可使陷阱捕获性能提升50%以上;最后通过实验验证了驱赶电极的有效性,且通过大量实验发现,高压电极布置驱赶电极后,陷阱捕获率可提高50%以上。因此,该文结果对提升直流GIL抑制金属微粒的能力具有一定的参考价值。

Free metal particles are more active in DC gas-insulated metal enclosed transmission lines(GIL)than in AC GIL,posing a severe challenge to the technical development and application of DC GIL.At present,active dynamic coordination of various particle suppression methods is the future trend.In order to further improve the effectiveness of metal particle suppression in DC GIL,firstly,a simulation model of the cooperation between the driving electrode and the particle trap is established,and the position cooperation effect between the driving electrode and the trap is optimized.When the high voltage electrode is arranged with a driving electrode,it significantly reduces the lift-off voltage of the metal particles while blocking the movement of the particles in two ways:(1)When the particles collide with the driving electrode,the particles have difficulty in overcoming shear deformation and friction energy on the tangential side due to the steepness of the driving electrode's circular surface;(2)The existence of an axial electric field on the sloping surface of the driving electrode causes the particles to be subjected to an electric field force in the opposite direction to the axial movement.Therefore,the particles are repelled and blocked by the driving electrode and have a probability of bouncing in the opposite direction on the axis toward the trap area.The simulation model uses the field strength design reference E0ofgas-insulated equipment and the trap capture rate as the boundary condition and objective function,respectively,and obtains the best capture efficiency of 70%when the position between the driving electrode and the trap is 18 mm.Secondly,the DC withstand voltage test has a special role in detecting certain local defects in the insulation compared to the AC withstand voltage test,and particles in DC equipment can easily penetrate the air gap and collide with the high voltage electrode to cause a discharge breakdown accident.Therefore,for DC GIS/GIL equipment,an optimized design of the DC ripening program,as shown in Fig.A1,has been developed to enable dynamic coordination measures with the driving electrodes and particle traps to suppress metal particles more effectively.■Finally,observation tests of particle motion with the cooperation of the driving electrodes,the traps,and the DC ripening program were carried out.The reliability of the simulation optimization results was verified.Experiments have shown that the trap capture rate can be increased by more than 50%after the high electrode placement of the driving electrode.That is,the driving electrode can effectively block the movement direction of the metal particles,so that they can be driven into the trap area to improve the trap capture efficiency for particles.Therefore,the results can further improve the ability of equipment to suppress metal particles,which is of great significance in improving the safety and reliability of DC GIL operation.