Stability Analysis And Reinforcement Research Of Z3 Cathead Tower

With the rapid development of China’s economy and society,people’s daily life is increasingly inseparable from safe and stable power supply.Frequent power grid accidents will not only seriously disturb the normal order of society,cause significant economic losses,and even cause social chaos.Investigate its reason,on the one hand,the expansion of power grid causes the load of transmission poles and towers to increase,on the other hand,frequent extreme wind disasters are also an important reason.To solve this contradiction,the most direct way is to overthrow and rebuild old transmission towers and rebuild new ones with better carrying capacity.However,the reconstruction of the new tower has the disadvantages of large investment,long construction period and power interruption.Therefore,it is of great practical significance to reinforce the existing old transmission towers and make them continue to be put into use.In this paper,the 220 kV double-loop linear Z3 cathead tower to be strengthened by Guangdong Power Transmission and Distribution Engineering Company of China Southern Power Grid is taken as the research object,and a series of stress analysis and reinforcement studies are carried out on this type of transmission tower.The main research contents of this paper include:(1)Based on the finite element analysis software ANSYS,this paper studies the modeling method of transmission tower,establishes the three-dimensional solid model of Z3 cathead tower,and studies its dynamic characteristics.(2)Linear and non-linear stability analysis of Z3 tower is carried out by ANSYS to determine the ultimate wind speed and weak position of transmission tower under four working conditions,in which the non-linear stability analysis considers the dual nonlinearity of structure geometry and material.Both stability analysis results show that the weak parts of Z3 tower are mainly concentrated in the middle and lower parts of the tower body.(3)Referring to a principal members reinforcement method proposed by Guangdong Electric Power Design Research Institute to strengthen the weak parts of Z3 Tower,and carrying out finite element analysis on the component test of the reinforcement method,the analysis results are compared with the test results to verify the rationality of the finite element modeling method,and the reinforcement effect of the main material is analyzed by establishing the reinforcement multi-scale model.(4)In consideration of the weak parts and failure modes of Z3 tower under strong wind,this paper presents several reinforcement methods of diaphragms and diagonal member,and carries out the non-linear stability analysis of the strengthened transmission tower.The results show that the non-linear stability of the strengthened transmission tower has been improved to a certain extent.