1. Tower can be divided into:
(1) bearing tower
① Tension tower: Its function is to segment the line properly, control the accident scope and bear the tension of broken line. Tension tower usually doubles as a small corner.
(2) Corner tower: used at the corner of the line, it bears the resultant force of the conductor corner and the ground wire under normal circumstances, and bears the tensile force of the broken wire under accident conditions, which also plays a role in controlling the accident scope.
(3) Terminal tower: used at the starting point and the end point of the line, which can bear large tension difference of grounding conductor.
④ Special tower: there are bifurcation tower, tension transposition tower and tension crossing tower.
(2) Straight tower
It is used in straight sections of lines to support vertical and horizontal loads of grounding conductors, and some straight towers are also used in small-angle corners. There are the following:
(1) straight tower.
② Straight-line corner tower.
③ Linear transposition tower.
(4) Crossing the iron tower in a straight line.
2. According to the different manufacturing materials, towers can be divided into rod type and tower type:
(1) Types of poles and their service conditions
(1) Reinforced concrete poles: The commonly used types of reinforced concrete poles are single pole and double pole, with and without cables. The tower line can bear large wind load and broken line load, which simplifies the tower structure and saves materials, so it is widely used.
● 35 ~ 1 10 kv single-loop linear pole
This kind of pole bears less load, and is generally designed as a single pole with wires arranged in a triangle. It is characterized by low center of gravity, good stability, simple structure, no need to pull wires, but the buried depth is relatively large, generally 2.5 ~ 3m m.
There are two kinds of cross arms of linear single rod: fixed and rotary. The rotary cross arm is used to reduce the torque after the main rod breaks.
● 35 ~ 1 10 kV single-loop carrier (with guy)
35 ~ 1 10KV single-loop load-bearing poles refer to straight-line tension poles, corner poles and terminal poles, which bear a large load. When using reinforced concrete poles, it is generally necessary to pull wires to balance the tension between wires and ground wires, and the shapes are A-shaped and portal. The "A" shape is formed by the combination of tip-pulling rods; Most portal rods are composed of ~ 300 equal-diameter rod segments.
When the rotation angle is large and the load is heavy, the iron tower is often used.
● 35 ~ 1 10 kV double-loop portal linear pole
The reinforced concrete straight-line double poles all form a portal shape, so it is also called portal pole, which is the main pole shape of 1 10kV line. Because of the large bearing capacity of the double poles, the horizontal arrangement of the wires can easily meet the electrical requirements, and the lightning resistance level is high, and it can prevent the wires from bumping during uneven deicing, so it is more suitable for using the door-type double poles in large cross-section wires, large span, heavy minefields and heavy ice areas.
There are many kinds of door-type linear double bars, only fork beams are set without pulling wires, only pulling wires are set without fork beams, and both fork beams and pulling wires are set. Linear bipolar cable is used to bear the tension of wire breakage and wind load, and at the same time, it increases the stability of poles along the line. There are two kinds of stay wires: V-shaped and X-shaped. X-shaped cables have better load resistance than V-shaped cables, and there is no fork beam.
(2) Thin-walled centrifugal concrete filled steel tubular pole:
It is a hollow composite member made by pouring concrete into thin-walled steel pipes and centrifuging. The wall thickness of steel pipe is 3-5 mm, and the wall thickness of concrete after centrifugation is 25-35 mm. It can give full play to the characteristics of steel and concrete and has good working performance. Compared with reinforced concrete poles, under the same bearing capacity, it can reduce the section size, reduce the amount of concrete, reduce the weight of components and facilitate construction and installation. The steel formwork can be cancelled during processing, and the specification and length of components are not limited by the steel formwork, and steam curing is not needed, which can solve the cracking problem of concrete poles. This rod type has been used in 1 10-220 kV transmission line.
(3) Tapped steel pole: mainly used for 35- 1LOkV power transmission and transformation project to supply power to urban areas. Although its cost is relatively high, it has the advantages of less land occupation and narrow corridor when used in urban lines, and it is beautiful, straight and concise, which is in harmony with the urban environment.
(2) The types of iron towers and their conditions of use.
The iron tower is the most commonly used support for high-voltage transmission lines. At home and abroad, most of them are space truss structures made of hot-rolled equal-limb angle steel and assembled by bolts. In a few countries, cold-formed steel pipes, steel pipes or concrete filled steel pipes are used, and steel products are hot-dipped galvanized for corrosion protection. According to the structural and mechanical characteristics, iron towers can be divided into two categories: stay towers and self-supporting towers.
As far as the appearance is concerned, the stay tower can be divided into three types: the shape with triangular wire on the upper part, the cat's head type, the door type with transverse wire, and the V type. And an inner stay tower with vertical self-support.
② Self-supporting tower
● Self-supporting linear tower: it can be divided into two types: the shape with triangular wires on the upper part, the bird bone shape, the cat head shape and the glass shape with transverse wires.
Zigzag tower is a kind of self-supporting tower, which is often used in 1 10kV lines. Simple structure, mostly narrow foundation, less floor space, suitable for passing through residential areas and hillside areas. The stay tower is a truss structure composed of angle steel, which is made into a square slender member and then forms a tower shape. Its bottom is hinged with the foundation, and it must have a stay wire and cannot stand on its own.
● Self-supporting double-ring towers: drum-shaped, inverted umbrella-shaped, regular umbrella-shaped and butterfly-shaped towers are widely used in China at present, and butterfly-shaped towers are generally used for long-span towers.
● Self-supporting load-bearing tower (including corner tower and terminal tower)
Self-supporting load-bearing towers are mainly glass-shaped, rod-shaped and double-ring portal (see Figure 2G31kloc-0/053-5). Because the phase conductor in the dry tower is directly hung on the tower body, the length of the lower cross arm is shorter than that of the glass tower, and the structure is simpler, so it is more economical.