Line towers can be classified according to structural materials, use functions and structural types.
Shan According to structural materials can be divided into wood structure, steel structure, aluminum alloy structures and reinforced concrete structure of several towers. Because of its low strength, short life span and limited maintenance, the timber tower has been eliminated in China. Steel structures are divided into trusses and steel pipes. Lattice truss towers are used most, and are the main structures of ehv-above lines. The aluminum alloy towers are used for transporting particularly difficult mountainous areas because of their high cost. The reinforced concrete poles are made of centrifugal machine and steam curing.
Shan according to the structure of the form can be divided into free-standing tower and guyed tower two categories. Self-reliance Towers are built on their own basis to stabilize the towers. The Guyed tower is installed in the tower head or tower body symmetrical pull line to firmly support the tower, the tower itself only bear vertical pressure. This tower saves nearly 40% of steel, but the distribution of the tillage is unfavorable to the agriculture and forestry industry, and the scope of use is limited. Because the mechanical property of Guyed tower is good, it can resist storm attack and the impact of line disconnection, the structure is stable, so the higher the voltage, the more the line application of Guyed tower.
The Shan can be divided into Lita, linear tower, transposition tower and large span high tower by using function. The circuit number of transmission lines erected by the same tower can be divided into single return, double return and multiple loop towers. The load-bearing tower is the most important structural link in the transmission lines.