| The security and stability of electric network operating is important to national interest and people’s livelihood. As the artery of electric network, electric transmission line is a vital implement. Meanwhile, the normal working state of electric transmission tower guarantees the stable working of electric network. Recently, the happening of the collapsing accidents of tower-line system threatened the security of electric network. Therefore, a total understanding of static and dynamic characteristics of transmission tower under different load conditions such as wind and leading wires, and researching the interaction between tower and tower-line system, are important in enhancing the security of power grid system both in theory and engineering.In this article, the finite element software ANSYS12.0is used as the analyzing platform, transmission towers and tower-line systems for later analyses are modeled, some solo towers such as the glass-shaped ZB39tangent tower, the glass-shaped ZB33tangent tower, the SDG42tension resistance tower, the JT43Angle tower are modeled, and five types of tower-line systems are there, including the one tower with two lines system, the two tower with three lines system, the three tower with four lines system of glass-shaped ZB33tangent tower, the one tower with two lines system of glass-shaped ZB39tangent tower and the one tower with two lines system of JT43angle tower. At the same time, the article advanced the processing methods of different loading cases, such as in wind, ice, earthquake, foundation settlement, disconnection and installing situations.According to the transmission line design standards, the subsection wind load of solo towers under maximum wind design are required and loaded, towers are the ZB39tangent tower, the SDG42tension resistance tower, the JT43angle tower. Take the example of the ZB39tangent tower, the curve of the equivalent stress distribution of main material with the height under maximum wind design is obtained, referring that the effect of self-weight of transmission line could be neglected while doing the maximum wind design analysis. Meanwhile, by studying the distortion, stress and axial force of members of three towers which are the ZB39tangent tower, the SDG42tension resistance tower, the JT43angle tower under maximum wind design, curve of axial force distribution with the height in main materials of three of them are obtained. Researching the static characteristic of the one tower with two lines system of ZB33tangent tower, curves of the displacement of sag of the leading wires under different wind velocity and wind angle are obtained, different wind velocity is recorded25.30m/s,28.28m/s,31.00m/s, and different wind angle is recorded0°,30°,45°,60°,90°.The mechanical property of transmission tower under special cases such as ice, earthquake, foundation settlement, disconnection and installing situations are studied. Considering the uniformity iced situation, the coupling effect of one tower with two lines system of ZB33tangent tower under different ice thickness is studied by applying transient force on the nodes of transmission lines, discovering that when the maximum ice thickness that is30mm is reached, sag of the earth wires is17.5m, sag of the leading wires is1.7m, while the leading wires is17.8m up the ground, satisfying the safety figure required14m. Considering the effect of transmission tower caused by foundation settlement, curve of the change of equivalent stress in members of ZB33tangent tower is obtained by analyzing their internal force in different settlements. Making use of the practical settlement measured in mining area of Shuang shi yin, which is a ZB33transmission line system, a settlement of60mm is analyzed, and put forward that installment of the stiffening plate in the base of tower would weaken the effect to the tower caused by large settlement. Studying the effect of the SDG42tension resistance tower in disconnection case, discovering that tower is in a safe state and tilted members in the disconnection end of tower cross arm is the weak position. The article studied the static characteristic of ZB39tangent tower in installment case that is52kN, finding that the superior surface of tower cross arm suffer strong tension, while maximum stress focuses on the hanging point, which tend to appear misbalance in the cooperation of tensile force and bending moment. Then, make the example of ZB39tangent tower in foundation settlement case, command streams for rapid loading are listed.The mode analyses are carried out concerning ZB39tangent tower, SDG42tension resistance tower and JT43angle tower, attaining their former ten self vibration frequency and vibration mode correspondingly, finding that tower body and tower leg are tend to appear local mode, and strengthened SDG42tension resistance tower by adding tower diaphragm. Take the example of the one tower with two lines system of ZB33tangent tower, studying the effect of transmission lines made to the mode of transmission line system. According to the results of infinite element mode analysis, the accounting equation of first self vibration frequency of the500kV glass shaped iron tower is corrected. The spectrum analysis of ZB39tangent tower is carried out in the structural dynamic wind making use of the Davenport power spectrum, presenting that the maximum displacement appears in the tilted member in the windward side of tower body. When considering the effect earthquake made to glass-shaped ZB39tower in the form of transient momentum, finding that the tower is unable to resist the magnitude-8earthquake. |
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