| Substation is an important part of the lifeline system in China,and is the premise of other lifeline system operation,which plays a vital role in the development of the country and the improvement of people’s lives.Traditional substations are mostly outdoor substations,which occupy a large amount of land resources and require a good surrounding environment.The indoor substation has the characteristics of energy saving,environmental protection,convenient construction,easy management and convenient maintenance,which is on the behalf of the development trend of substation.Prefabricated steel structure has many advantages,such as light weight,high strength,uniform material,good plasticity and toughness,high degree of industrialization,convenient demolition and construction,etc.Therefore,it is of great significance to apply the prefabricated steel structure to the indoor substation.In this paper,the 220kV indoor substation is designed,and finite element models are established with the FEM design and analysis software MIDAS/GEN to carry out the analysis and research on the substation in many aspects.The main work and achievements of this paper are as following:(1)Three structural schemes of steel frame,steel frame-braced and concrete-filled steel tube are analyzed,and the internal force,deformation,steel consumption and construction difficulty of the them are compared.The comparison results show that the period,displacement,steel consumption and other indexes of the steel frame-braced structure are better than those of the other two schemes,and the construction is convenient.Therefore,the optimal solution is steel frame braced structure.(2)Static Pushover Analysis on the steel frame-braced structure is carried out,respectively under the lateral modal distribution loading mode and constant acceleration distribution loading mode with the“displacement control”method applied in the X and Y directions respectively,under frequent and rare earthquakes,the layer shear force,interlayer displacement,interlayer displacement angle and the order of plastic hinge of the structure are analyzed.The analysis results show that the structure is in the elastic state under frequent earthquakes,some components yield plastic hinges under rare earthquakes,and the plastic hinges are all in the first yielding state.(3)Incremental Dynamic Analysis is curried out on the frame-braced structure.select 10 seismic waves,respectively,the peak acceleration of these wave is adjusted to70cm/s~2,150cm/s~2,196cm/s~2,300cm/s~2,400cm/s~2for Incremental Dynamic Analysis.Comparing the base shear,vertex displacement,interlayer displacement,plastic hinge out hinge sequence and other indicators.The analysis results show that the increase of peak acceleration of the same seismic wave,the base shear,vertex displacement and interlayer displacement of the structure increase,the base shear and vertex displacement calculated with different seismic waves are quite different under the same seismic intensity,but the waves tend to rise with the increase of seismic intensity;when the peak accelerated speed of wave is 400 cm/s~2,plastic hinges occur to the braces of structure and most hinges are at level2 and level3.(4)Displacement results of Static Pushover Analysis and Incremental Dynamic Analysis are compared and analyzed.The results show that the mean time-history displacement of the structure is different between the results of Static Pushover Analysis and Incremental Dynamic Analysis under frequent earthquakes and rare earthquakes.Under frequent earthquakes,the results obtained by Incremental Dynamic Analysis are more conservative,which shows that the mean time-history displacement obtained by Incremental Dynamic Analysis is greater than that obtained by Static Pushover Analysis using modal distribution and acceleration constant distribution.However,under rare earthquakes,the results obtained by Static Pushover Analysis method with modal distribution are more conservative.The results obtained by Static Pushover Analysis method with modal distribution are larger than the results obtained by Incremental Dynamic Analysis and the results obtained by Static Pushover Analysis method with constant acceleration distribution.Therefore,the traditional Static Pushover Analysis method and Incremental Dynamic Analysis method are used to carry out the Elastoplastic Analysis of the structure,and the displacement results of the two methods under frequent and rare earthquakes are compared respectively,and the envelope values are selected for the subsequent design basis.(5)Finally,the seismic performance of the frame-braced structure is evaluated and some relevant design suggestions are given. |
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