The transmission line adopts angle steel tower, and the main component adopts angle steel lattice tower, which is the support structure of the overhead transmission line and supports the conductor and ground wire. It ensures that the conductor meets the distance requirements from the ground and objects, and can withstand the load of the conductor, ground wire and tower itself, as well as external loads. Angle steel, commonly known as angle iron, is a long strip of steel with two sides forming right angles. There are equilateral angle steel and unequal angle steel. Equilateral angles have equal width on both sides. Its specifications are expressed in mm dimensions of width ×width × thickness. For example, “∟30×30×3” means an equilateral angle steel with a width of 30 mm and a thickness of 3 mm. It can also be expressed by model, that is, width, in centimeters, such as ∟3#. The model number does not represent the dimensions of different thicknesses within the same model, so the width and thickness dimensions of the angle steel need to be filled in on contracts and other documents to avoid using the model number alone. The specifications of hot-rolled equilateral angle steel are 2#-20#. Angle steel can be assembled into various stress-bearing components according to different structural needs, and can also be used as a connecting component between components.

The basic knowledge and technical requirements for transmission line angle steel tower drawings involve many aspects such as material selection, component size, connection design, construction requirements, and drawing preparation. The drawing content includes general drawings and structural drawings. The structural drawing should be divided into sections such as brackets, cross arms, tower bodies, and tower legs. In the structural drawings, except for standard parts such as bolts, flanges, clamping plates, foot pins and washers, all parts should be numbered.