Finite Element Analysis And Research For Mechanical Property Of GIS Busbar

With the social demand for electricity increasing gradually, there are more and more500kV and above high-voltage substations. In the region of supply center, it is necessary to build smaller, safe and reliable substation equipment. In the construction of substation in gim at home and abroad, it gradually introduces a new closed switch of equipment-Gas Insulated Switchgear GIS. GIS is filled with SF6as electric insulating and arc-quenching medium, running with good arcing performance and high safety factor. GIS is exposed to the outdoors, and the force situation is complex. Gas leakage accidents often occur due to external damage, equipment aging, unreasonable installation process, etc. The accidents do damage to person, environment and equipment. Therefore, total understanding and research of static and dynamic characteristics of GIS equipment under different working conditions are important in enhancing the security of power grid system both in theory and engineering.The research did multi-condition simulation analysis to the main busbar of Linzi220kV GIS substation and studied the technologies of geometric modeling, meshing, contact definition and load application. The simulation results obtained the distribution of stress and deformation of busbar under windy condition, variable temperature condition, seismic condition and uneven settlement condition. It did comprehensive research to the static and dynamic response characteristics of the busbar in operation process and proposed improvements advices to the structure optimization.According to the design rules, the research did stress analysis to the busbar shell and flange in normal operation condition. It did finite element analysis to a typical four-way busbar casing under working pressure0.1-0.6MPa. The results showed that the stress concentration occurred at the outer surface of the shoulder of the cylinder cutout. Under the pressure of0.5MPa, the maximum stress was60.34MPa and the structure was safe. The research studied the stress distribution of a three-way busbar, taking working pressure and bolt preload as variables. The results showed that the maximum stress appeared at the connection of the flange and the tube. When the working pressure is0.5MPa and the bolt preload is8000N, the maximum stress of bolts and flange were33.3MPa and21MPa respectively. The stress values were far less than the permissible stress and the structure was safe.In the analysis of windy condition, the research applied loads of constant wind, gust and fluctuating wind to the busbar. The simulation results showed that, compared to the model suffering static wind, the model suffering dynamic wind had greater stress and smaller displacement. The maximum stress appears at the surface of bellows and the maximum displacement appears at the east end. The busbar satisfies the strength requirement in windy condition. In the modal analysis of busbar, the self-locked frequency was calculated to be9.23Hz. According to the modal finite element analysis, the research obtained the six lowest order inherent frequency. The results showed that when the busbar is longer than16.9m, the inherent frequency is less than self-locked frequency. The structure is under the danger of resonance. The form of structural failure is the connection failure of support insulator and flange. In the analysis of variable temperature conditions, the maximum displacement of the busbar appeared in the bellow. In the variable temperature conditions of-5～70℃and35～70℃, the maximum stress appeared at the connection of the main busbar and the branch which were167.29MPa and167.19MPa respectively. The maximum stress was beyond the permissible stress and the structural failure will occur because of the material yield in summer. The research tested the anti-seismic capacity of the busbar of Linzi GIS substation with El-centro seismic wave in different intensity and direction. The results showed that the maximum stress appeared at the opening of the busbar. Compared to the model suffering Z-directional seismic wave, the model suffering X-directional seismic wave had greater stress. In nine seismic waves, the maximum stress of the busbar was82.68MPa which was less than the permissible stress. In the uneven settlement conditions, the largest differential settlement of adjacent strut is1.24mm and the overall settlement ratio is1.79mm/20m and the largest settlement is1.79mm. The structure satisfies the horizontal accuracy of transformer substation.