Gas insulated switchgear (GIS) is a widely used equipment and the expansion of existing GIS equipment is an urgent need to improve the transmission capacity of substation. In the GIS expansion process

the mechanical and electrical connection of the original equipment and the new equipment is achieved by the connection busbar and stability of the connection busbar is the basic guarantee for normal operation of GIS. In this paper

a connection busbar arranged in the same horizontal position is designed and the stress of the busbar under the short-circuit current is simulated and analyzed. The finite element model is set up

the short-circuit current with a peak value of 125 kA is applied and the stress time history curve within 150 ms is obtained. The results show that the stress of each part of the busbar basically increases and then decreases with time

and the maximum stress occurs at about 12-20 ms. The maximum stress at the bolt is significantly greater than that of the wire. The main stress point of the insulating spacer on both sides of the busbar is the inlay of the three-phase wire and

at the same time

the insulating spacer is subjected to the highest moment at the phase position with the highest short-circuit current. The study results in this paper can provide a reference for the design of the connection busbar during expansion process of GIS.