特高压工程电力跨越架力学分析

发布时间：2018-10-23 09:27

【摘要】：我国特高压输变电工程建设世界领先。特高压工程具有输电容量大,传输距离远,输送损耗小和占地面积小等特点,是实现电力资源配置的重要方式,可大大提升我国电网的输送能力。输电线路架线施工需要跨越已经建成的电网、高铁、高速公路等重要设施,为保证这些设施的安全正常运行,需要采取跨越封网防护措施。本文对跨越技术进行了梳理分析,并就主要被跨越物类型所适用跨越架形式进行了总结。建立了跨越架力学模型,进行了数值模拟分析。对跨越架的剪刀撑布置形式、构造形式(立杆间距、大横杆间距、小横杆垂直及水平间距、排间距等)、高度、排数对跨越架力学性能的影响进行了分析,结果表明构造参数对跨越架的影响明显,在小横杆立面设置剪刀撑的跨越架较仅四周设置剪刀撑的跨越架最大位移和应力更小,稳定性更好,建议实际工程中采用小横杆立面设置剪刀撑的形式;随跨越架高度的增加,最大位移随着荷载增加而增大的趋势更快,稳定性快速衰减;增加跨越架的排数有利于降低跨越架应力与位移,增强其稳定性。对跨越架在导线冲击下的动力学响应进行了分析,结果显示力学简化模型三跨连续梁较简支梁更能准确反映跨越架杆件在冲击作用下的动力响应。导线冲击架体时,随冲击质量的增加架体的瞬时位移及应力的幅值呈线性增加趋势,且跨越架振动恢复至稳定状态所需时间更久、波动幅度更大。导线的下落高度越高,导线落到架体时所含的能量越大,冲击引起的位移和应力亦越大。冲击位置不同,引起的效应也不同。建立了跨越架与封网装置的耦合模型,研究了跨越架高度、封网形式、荷载在封网装置上的作用位置及两侧跨越架的高差对跨越架力学性能的影响。研究结果表明绝缘网的变形有利于减小导线下落对跨越架的直接冲击,并有效的分散导线荷载在跨越架上的作用位置,有利于提高跨越架的安全性。封网形式影响承载索的弧垂,进而改变承载索与跨越架之间的夹角使作用于跨越架的荷载方向发生变化,但在档距较小时影响甚小。两侧跨越架的高差对较高侧跨越架的位移和应力的影响较小,对较低跨越架的影响比较大。
[Abstract]:China leads the world in the construction of UHV power transmission and transformation projects. UHV project has the characteristics of large transmission capacity, long transmission distance, small transmission loss and small area. It is an important way to realize the allocation of power resources, and can greatly enhance the transmission capacity of power network in China. Transmission line construction needs to span the power grid, high-speed rail, expressway and other important facilities, in order to ensure the safe and normal operation of these facilities, it is necessary to take measures to protect the network. In this paper, the cross-over technology is analyzed, and the main types of cross-over frame are summarized. The mechanical model of span frame is established, and the numerical simulation is carried out. This paper analyzes the influence of the arrangement form, structure form (vertical and horizontal spacing, row spacing, etc.), height and number of the span frame on the mechanical properties of the span frame, and the structure form (vertical bar spacing, large horizontal bar spacing, small horizontal bar spacing, etc.), and the influence on the mechanical properties of the span frame are analyzed. The results show that the influence of structural parameters on the span frame is obvious, and the maximum displacement and stress are smaller and the stability is better in the span frame with scissors brace on the elevation of the small horizontal bar than in the span frame with only scissors brace around. It is suggested that the form of scissors brace should be set on the elevation of small horizontal bar in practical engineering, and the maximum displacement will increase with the increase of the height of the span frame, and the stability will decrease rapidly with the increase of load. Increasing the number of span frames is helpful to reduce the stress and displacement of span frames and enhance their stability. The dynamic response of span frame under conductor impact is analyzed. The results show that the simplified mechanical model can accurately reflect the dynamic response of span frame member under impact compared with simply supported beam. The instantaneous displacement and stress amplitude of the frame increases linearly with the increase of the impact mass, and the vibration of the span frame needs a longer time to recover to the stable state and the amplitude of fluctuation is larger. The higher the falling height of the conductor is, the greater the energy is when the conductor falls into the frame, and the greater the displacement and stress caused by impact are. Different impact positions cause different effects. The coupling model of span frame and sealing device is established, and the influence of the height of span frame, the form of sealing net, the action position of load on the sealing device and the height difference between two sides of span frame on the mechanical properties of span frame are studied. The results show that the deformation of the insulation network is helpful to reduce the direct impact of the wire drop on the span frame, and to effectively disperse the position of the traverse load on the span frame, and to improve the safety of the span frame. The form of sealing net affects the sag of the bearing cable, and then changes the angle between the bearing cable and the span frame to change the direction of the load acting on the span frame, but the influence is very small when the space is small. The height difference of the two sides span frame has little effect on the displacement and stress of the higher side span frame, but it has more influence on the lower span frame.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM752

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