الوصف

Steel tower has many advantages such as heavy loading capability, long service life, good appearance and stability, so it has been widely used in electric power, communication, illumination fields. The steel tube towers are widely used in both domestic and foreign market. A transmission tower is a tall structure, usually a steel lattice tower, used to support an overhead power line. They are used in high-voltage AC and DC systems, and come in a wide variety of shapes and sizes. Typical height ranges from *5 to *5 meters (*9 to **0 ft),[1] though the tallest are the **6.5 m (1,**7 ft) Yangtze River Power Line Crossings at Jiangyin. In addition to steel, other materials may be used, including concrete and wood.

Tower structures can be classified by the way in which they support the line conductors. Suspension structures support the conductor vertically using suspension insulators. Strain structures resist net tension in the conductors and the conductors attach to the structure through strain insulators. Dead-end structures support the full weight of the conductor and also all the tension in it, and also use strain insulators.

Where the conductors are straight, a tangent tower is used. Angle towers are used where a line must change direction.

Four major functions of transmission towers are in use: suspension towers, terminal towers, tension towers, and transposition towers. Some transmission towers combine these basic functions. Transmission towers and their overhead power lines are often considered to be a form of visual pollution. Methods to reduce the visual impact include undergrounding.

A lattice steel tower is a steel framework construction. Lattice steel towers are used for power lines of all voltages, and are the most common type for high-voltage transmission lines.