A transmission tower mainly consists of three parts: the tower head, the tower body, and the tower legs. If it's a guyed tower, it also includes the guy wires. For towers with conductors arranged in a triangular pattern, the part above the lower crossarm is called the tower head; for towers with conductors arranged horizontally, the part above the horizontal end is called the tower head. For goblet-shaped and cat-head-shaped tower heads, the section from the horizontal end to the crossarm is called the tower neck, and the two sides are called curved arms. The first section of the frame located on the foundation is called the tower leg. The truss structure excluding the tower head and legs is called the tower body. The underground part of the tower pole, excluding the grounding device, is collectively called the tower foundation. Its function is to support the tower, bear the tower load, and transmit it to the ground.
The components at the four corners of the main truss of the transmission tower are called main members. To ensure the tower's shape remains unchanged and to improve the stability of the members and the torque in case of wire breakage, diagonal members are used to connect each plane of the main members. Some towers also have horizontal partitions in certain sections of the main members. To reduce the slenderness ratio of the components, some towers also have auxiliary members on the partitions or diagonal members.
The connection between the diagonal member and the main member, or the connection between the diagonal members, is called a node. The intersection of the center lines of the components at the node is called the center. The part between two adjacent nodes is called the gap. The distance between the centers of two nodes is called the node length. The horizontal distance between the center axes of two adjacent tower legs is called the tower root opening.
