Analysis Of Wind-Induced Vibration Response And Spatial Effect Of Fully-Combined Substation Frames With Lightning Rods

Lightning rod is an important lightning protection facility in high-voltage substations.In order to cover a certain protection range and achieve a good lightning protection effect,the lightning rod is usually installed on the substation frame,which is composed of round steel pipes and is a typical high-rise structure.The height is generally 10-30 m.As a result of working in the high altitude environment in the field all year round,the structure of the lightning rod is greatly affected by the wind load,and the wind vibration response is more significant,which causes a large number of stress cycles in the weak parts of the lightning rod.In recent years,the lightning rods of high-voltage substation frames have frequently broken in various regions of China,causing serious impacts.In the past,the research on the mechanical performance of the lightning rod of the framework was mainly focused on the material and static performance of the single rod.The research on the lightning rod of the framework was mainly based on the single structure.There are few studies on the overall structure of the fully-combined substation frame with lightning rods.Based on the above background,this paper uses ANSYS software to establish a finite element model of the lightning rod structure of the fully-combined substation frame,analyze its windinduced vibration characteristics,and compare the form of the fully-combined substation frame with the single-frame structure to study its spatial effect.The main research work of this article is as follows:(1)According to the basic characteristics of the local wind field and the characteristics of fully-combined substation frames with lightning rods,nodes at different positions are selected as wind speed simulation points,and the wind speed time history simulation is performed on each wind speed simulation point on the structure using the pulsating wind Davenport spectrum,and the wind speed time history curves of each point are obtained.(2)The ANSYS finite element software is used to model the fully integrated structure with lightning rods and without lightning rods,and the dynamic characteristics such as the natural frequency and mode of the structure are obtained through modal analysis.Pulsating wind loads with different wind direction angles under simulated strong wind are applied to the structure,and the dynamic time-history response of the structure under the wind load is calculated.Through the analysis and comparison of the response time-history data,the influence of the upper lightning protection on the windinduced vibration response of the fully-combined substation frame is studied,and the ways to reduce the wind-induced vibration response of the structure are analyzed.(3)By comparing and analyzing the wind-induced vibration response of the single-frame with lightning rods and the fully-combined substation frame with lightning rods,the influence coefficient of the space action is calculated,and the characteristics of the influence of the space action on the wind vibration response of the structure are analyzed.Based on the above results,the static loading analysis of the fully integrated with lightning rods is carried out,and compared with the dynamic response results,the displacement wind vibration coefficient of the lightning rods structure is obtained.Through the above work,the following conclusions are obtained:(1)The upper lightning protection has a greater impact on the structure of the full joint structure.After the lightning rod is installed,the overall natural vibration frequency of the structure is reduced,and the low-order vibration mode is mainly due to the bending of the lightning rod.At the same time,the response of the lightning rods is also affected by the lower structure.(2)The spatial action of the fully-combined substation frame can reduce the windinduced vibration response of the lightning rods in the X direction,but it will be amplified in the Y direction.For the framework itself,the response in the X direction has little effect,but there is a larger amplification in the Y direction;The displacement wind vibration coefficient of the lightning rods structure of the fully-combined substation frame is greatly affected by the installation location.It is recommended to adopt 3.0 for the framework itself and 3.3 for the upper lightning rods.