Wind-induced Dynamic Response Analysis Of Substation Framework With Lightning Rod Based On Two-Way Fluid-Solid Coupling

This paper uses a 500kV substation lightning rod breakage accident as the engineering background.this paper establishes the finite element model of wind-induced vibration response analysis of a typical structure lightning rod of a 500 kV high-voltage substation,uses two-way fluid-solid coupling numerical method to simulate and analyze the force characteristics of the prototype structure lightning rod,and optimizes the design of the structure lightning rod.On this basis,the wind-induced vibration response of the optimized structure is studied.Vibration response characteristics.The main work and conclusions are as follows:(1)The wind-induced vibration response analysis of the prototype lightning rod structure shows that the high-frequency vibration response of the upper of the lightning rod is significant,and it is greatly affected by the multi-order mode.The upper lightning rod is prone to cross-wind vortex-induced resonance,which is unfavorable to the overall force of the structure.Based on the above analysis,the helical strakes are applied to the first two sections of the upper part of the lightning rod to optimize the design,and the overall force analysis of the optimized structure of the lightning rod under different wind speeds and wind directions is carried out.The results show that the greater the wind speed,the greater the stress of the structure;in the basic wind speed,the maximum stress of the frame lightning rod occurs on the cross beam of the intersecting joint.With the increase of wind speed,the maximum value of the stress moves up along the lightning rod.When the wind speed reaches 28.461 m/s,the maximum stress of the first lightning rod at 45°,90°and 0°of wind direction angles exceeds the yield strength of the material successively,and the structure is unsafe.(2)The effects of structural optimization measures with additional helical strakes on the wind-induced response along wind direction and across wind direction are simulated and analyzed.The results show that the structural optimization measures can effectively suppress the vortex-induced resonance of the lightning rods;the amplitude of the vortex-induced resonance in the cross wind direction of the structure can be significantly reduced within the basic wind speed,but at large wind speeds,it will adversely affect the crosswind vibration of the structure.(3)By comparing and analyzing the response of the optimized frame lightning rod along the downwind direction and the crosswind direction,the results show that the crosswind response of the structure is in the same magnitude as the downwind response,and the joint action of the two should be taken into account in the structural design and stress analysis.The trend of the strain along each section of the lightning rod along the wind speed under different wind directions is considered comprehensively,it is found that the bottom of the second section,the third section and the fifth section of the lightning rod is the most unfavorable,which provides reference for engineering inspection and maintenance.(4)Based on the wind direction and wind speed information of the site,the maximum value of the hotspot stress amplitude of the lightning rod intersecting joints under different wind speeds in each wind direction is less than the critical stress amplitude of the structure(68.65N/mm~2).Which indicates that the vibration cyclic load of the lightning rod will cause fatigue damage to the intersecting joints,but it will not affect the normal use of the joints within the design life.