Thermal Stress Analysis Of Overlong Substation Steel Frame

Substation steel lattice frame is the joint name of the major structures of outdoor wires and equipment like substations, transformer stations and the like. At present, the structural style of substation steel lattice frame is basically molded, among which low-voltage and medium-voltage substation steel lattice frame often adopt the form of diagonal columns and the space truss composed by steel beams, 330 kV substation steel lattice frame often adopt the form of annular diagonal columns composed by steel tubes or concrete and steel tubular structures, and extra-high voltage substation steel lattice frame often adopt the form of lattice composed by steel beams. But in terms of the special requirements posed by substation, the over-length structure is often adopted, but there are still some problems on the study of temperature stress of the over-length structure composed by steels, which has been architects’ and scholars’ concerns. Concerning this problem, in order to obtain the limiting length of continuous bents and continuous rigid frames, which are two major structural styles of substation steel lattice frame, under different temperature loads, this paper takes two substation steel lattice frame as engineering backgrounds, which are 220 kV outdoor power distribution apparatus structure in a new project developed by 500 kV transformer stations in Shixi and 220 kV outdoor power distribution apparatus structure of 500 kV transformer stations in Xincheng. The study mainly includes the following two aspects:(1) Building ANSYS modeling in accordance with two substation steel lattice frame. Through analyzing finite elements, different temperature loads of substation steel lattice frame are calculated. When meet the ultimate limits and serviceability limits, the substation steel lattice frame in different length were set, the stress ratio,displacement and stability of all bars of switchyard structures were calculated, from which the transformation laws of stress and stability of bars of switchyard structures could be concluded, and the maximal length that continuous rigid continuous bentsand continuous rigid frames could reach under different temperature loads could be concluded as well.(2) In order to reduce temperature stress, the purpose of mitigating temperature stress could be achieved by installing slipper blocks on substation steel lattice frame to mitigate structural distortion. The maximal length that substation steel lattice frame could reach after installing slipper blocks under different temperature loads could be concluded by checking the stress ratio, displacement and stability of all bars of substation steel lattice frame under different temperature loads after installing slipper blocks.The maximal length that substation could reach with and without slipper blocks were compared.Through calculations and analysis, the transformation law of length of overlength structures with and without slipper blocks under different temperature loads were revealed, which can serve as a reference to the engineering design of ubstation steel lattice frame in the future.