摘要
A large amount of metal dust is often generated during production and operation of Gas Insulated Switchgear/Gas‐Insulated Transmission Line,and insulating fibres are very easy to mix in during assembly.The discharge phenomenon induced by these two impurities remains unknown.By setting up a test rig with parallel electrodes,the discharge characteristics of metal dust and linear insulating fibres under the negative DC voltage were studied separately and jointly.The obtained research results indicate some interesting phenomena that the metal dust may render‘sand storm’motion characteristics under the action of the electric field,and the linear insulating fibres appear to show‘standing’,‘jumping’,‘flying fire’and other phenomena.A small amount of dust and fibres alone present little effect on the breakdown voltage of the air gap.However,while the insulating fibres and metal dust coexist,the metal dust will be adsorbed on the surface of the insulating fibres,then the surface charge of the fibres is reallocated,and the discharge phenomenon at both ends of the fibres is enhanced,so that the insulating fibre exhibits similar movement and discharge characteristics to the linear metal particles.At the same time,the fibres with dust absorbed on will result in an air gap breakdown voltage drop of approximately 25%-40%.What's more,if the discharge of fibres and the‘sand storm’movement of the dust coexist,it may directly lead to‘explosion’of the moving dust,causing severely ablation of the plate surfaces,and thereby the degree of destruction increases dramatically.
基金
supported in part by the National Basic Research Program of China(973 Program)(2014CB239500)
National Natural Science Foundation of China(51737005&51807060)
Beijing Municipal Natural Science Foundation(3192036)
the Fundamental Research Funds for the Central Universities(2018MS165).
