CN100577974C - Double-circuit compact linear transmission tower on the same tower - Google Patents

Abstract

The double-circuit compact linear transmission iron tower with the same tower of the present invention arranges the wires in a double-circuit compact inverted triangle arrangement on the same tower, and arranges the ground wire at a negative protection angle, which effectively reduces the tower height and improves the 500KV same-tower The lightning resistance level of parallel transmission lines improves the safety and reliability of operation. After improving the bar system and inter-node arrangement of the double-circuit parallel-frame compact tower on the same tower, the size control of the tower head and each part of the cross-arm, and the optimization of the slope of the tower body, the 500KV double-circuit compact linear The steel consumption of the tower is reduced by nearly 30% compared with the conventional drum-shaped straight tower; after the height of the iron tower is reduced, the force of the foundation of the tower is reduced, and the consumption of foundation concrete is about 10% lower than that of the conventional double-circuit 500KV line with the same tower.

Description

Double-circuit compact linear transmission tower on the same tower

technical field

The invention relates to a power transmission equipment, especially a brand-new power transmission tower used in a 500 kV double-circuit power transmission line on the same tower.

Background technique

At present, the straight-line towers used in my country's 500 kV double-circuit transmission lines on the same tower are conventional straight-line towers with three-phase conductors arranged vertically and suspended on both sides of the tower. Under the premise that the distance between the wire and the ground meets the requirements of the regulations, the height of the iron tower usually reaches 60m-70m, and the average line corridor occupied is 22m.

As shown in Figure 1, the design tower height of existing conventional double-circuit 500kV line towers on the same tower often exceeds 60m, which not only affects the lightning protection ability, but also the reason for the high steel consumption index of the previous 500kV double-circuit drum towers. one. The height of the tower with a height of 33.0m is usually above 56.0m, approaching 60.0m or above 60.0m. Nearly 1.6 or greater than 1.6, according to the current DL/T5092-1999 "Technical Regulations for Design of 110-500kV Overhead Power Transmission Lines", for towers with a total height of more than 60.0m, it is necessary to adopt the current national code "Building Structure Load Code" from bottom to top Increase step by step and the weighted average should not be less than 1.6.

Therefore, after the promulgation and implementation of DL/T5092-1999, the steel consumption index of 500kV double-return drum towers with the same tower is higher than that when SDJ3-79 was implemented in the past. From the perspective of the project as a whole, the 500kV double-circuit double-circuit drum-shaped straight towers are either close to 60.0m or above 60.0m. The wind pressure adjustment factor is either close to 1.6 or greater than 1.6. In this way, it will inevitably lead to an increase in the construction cost of the 500kV double-circuit tower with a drum-shaped straight-line tower. It can be seen that reducing the height of the whole tower and controlling the wind pressure adjustment coefficient at 1.5 should be a feasible way to reduce the steel consumption index; and the wind pressure height variation coefficient can also be reduced, and only this can reduce the wind load acting on the whole tower by 6- 7%.

Contents of the invention

The purpose of the present invention is to provide a new type of iron tower, which realizes the popularization and application on the 500kV double-circuit transmission line on the same tower, so that the construction of the 500kV double-circuit transmission line on the same tower in my country can reduce the construction investment and improve the natural transmission of the line. The purpose of reducing the power, reducing the electromagnetic impact on the environment, and improving the lightning resistance level of the line. The anti-lightning performance of the double-circuit 500kV compact line on the same tower is better than that of the double-circuit 500kV conventional line on the same tower, which can improve the lightning protection ability of the transmission line and is beneficial to production and operation.

Its lightning protection performance is compared in the following table:

line type  Compact double-circuit line on the same tower   Conventional double-circuit line on the same tower Lightning resistance level (kA) 165 139 Trip rate (times/year. Hundred kilometers) 0.116 0.294

In addition, another purpose of the present invention is to effectively reduce the height of the tower by arranging the conductors in a double-circuit parallel compact inverted triangle arrangement on the same tower, and through the rod system and section of the double-circuit parallel compact tower on the same tower. The layout of the tower head, the size control of each part of the cross-arm, and the optimization of the slope of the tower body have been improved. The 500kV double-circuit compact linear tower of the present invention reduces the steel consumption by nearly 30% compared with the conventional drum-type linear tower. ; After reducing the height of the iron tower, the force of the foundation of the iron tower is reduced, and the consumption of foundation concrete is about 10% lower than that of the conventional double-circuit 500kV line on the same tower.

For this reason, the present invention has adopted following technical scheme:

A double-circuit compact straight-line transmission iron tower on the same tower, which includes a tower body, a tower head, and conductors. Arranged on both sides of the tower body, the iron tower has a T-shaped structure as a whole.

Wherein the two ends of the cross arm respectively extend downwards with a folded arm.

The arrangement of the conductors is as follows: a circuit of three-phase conductors is respectively arranged on the crossarms on both sides of the tower body. The three-phase conductors are arranged in a compact form and arranged in a triangle. Two V-shaped strings, and the lower phase wire is hung on the end of the cross arm and the tower body, forming a V-shaped insulator string, between the intersection point of the upper two-phase V-shaped strings and the lower phase wire There is a hanging string, and the three-phase wire V-type insulator string meets the requirements of the electrical clearance between the phases and the ground at the same time.

The V-shaped string of the lower-phase conductor is in a relaxed state, and the vertical load is borne by the middle hanging string; under normal working conditions, two V-shaped strings of the three-phase conductor always maintain two working strings and one string relaxes.

Each of the three-phase wires consists of 6 wires to form a phase.

The height of the iron tower is between 40m-50m; the average line corridor it occupies is 24m.

Compared with the double-circuit drum type tower commonly used in engineering, the overall height of the tower is 17.0m shorter than the conventional type, which improves the lightning protection ability, and at the same time, the ground wire adopts a negative protection angle, which also avoids lightning strikes caused by lightning; After optimizing the control size of each part of the tower, the weight of the single-base tower is 27% lower than that of the conventional drum tower; the corridor occupied by the line is slightly larger than the conventional line by 1.0m; times.

Description of drawings

Fig. 1 is the structural representation of conventional transmission iron tower;

Fig. 2 is the structural representation of compact power transmission iron tower of the present invention;

Fig. 3 is a schematic diagram of the practical application of the present invention.

【Description of figure number】

1 tower body 2 tower head

21 Cross arm 211 Folding arm

22, 23 V-shaped string of upper phase wire 24 V-shaped string of lower phase wire

25 medium hanging string

Detailed ways

In order to make the structure and composition of the present invention clear to your examiner, as well as the overall operation mode, the description is as follows in conjunction with the drawings:

The 500kV same-tower double-circuit compact linear tower described in the present invention is a brand-new tower type different from previous tower types. The determination of the size of the tower head depends on the layout of the conductors. Therefore, on the basis of the analysis of the 500kV conventional drum-shaped tower with double circuits in the same tower in my country, after the research and technical and economic comparison of various tower head layout schemes, in many schemes Among them, a brand-new tower-type technical solution of the T-shaped tower of the single-layer cross-arm of the present invention has been developed.

The tower head layout of the 500kV double-circuit parallel tower compact transmission line tower head, due to the characteristics of the compact layout of the three-phase conductors, the V-shaped insulator strings of the lower phase conductors must meet the requirements for the electrical clearance of the upper two-phase conductors, basically forming two phases. The end of the cross-arm of the folded arm and the tower body are used to hang the V-type insulator string of the lower phase wire, which is like a T-shaped tower in English capitals. The two circuits are respectively arranged on both sides of the tower body, as shown in Figure 2: The transmission tower It includes a tower body 1, a tower head 2 and wires. The key point is that the tower head 2 includes a single-layer cross arm 21, and the two ends of the cross arm respectively extend downwards with a folded arm 211, which is symmetrically distributed on the tower body. 1 On both sides, the two loop wires are respectively arranged on both sides of the tower body, and the iron tower has a T-shaped structure as a whole.

Wherein the arrangement of the conductors is as follows: a circuit of three-phase conductors is respectively arranged on the cross arms 21 on both sides of the tower body 1, and each of the three-phase conductors consists of 6 conductors to form a phase. The three-phase wires are compactly arranged and arranged in a triangle, wherein the upper two-phase wires 22, 23 are hung side by side on the cross arm 21 and have crossings, forming two V-shaped strings, while the lower phase wires 24 are hung on the cross arm 21. The end of the arm 211 and the tower body 21 form a V-shaped insulator string, and a middle hanging string 25 is hung between the intersection point of the upper two-phase V-shaped strings and the lower phase conductor, and the lower phase conductor is 24V The V-shaped insulator strings meet the electrical clearance requirements of the V-shaped strings 22 and 23 of the upper two-phase conductors at the same time. The V-shaped string of the lower phase conductor is in a loose state, and the vertical load is borne by the middle hanging string 25; during normal working conditions, two strings of the V-shaped string of the three-phase conductor are kept working and one string is slack.

The 500kV double-circuit compact tower type in the same tower of the present invention is mainly aimed at the characteristics of the hanging strings in the V strings of the lower phase insulators, the working mechanism of the lower phase three strings combination, the working status of the combination strings under various working conditions, and whether the lower phase three strings are super The static state was analyzed. The characteristics of the load on the cross-arm of the T-shaped tower, the torsion effect of the small folded arm at the far end of the cross-arm on the cross-arm, and the ability of all parts of the tower to resist deformation are similar to those of the typical 500kV that have been tested in my country in the past two decades. The iron towers have been analyzed in detail, as follows:

1. The comparison between the 500kV double-circuit compact linear tower on the same tower and the conventional double-circuit linear tower on the same tower is shown in the table below:

Compact Conventional The wires are arranged in a triangle The wires are arranged vertically The three phases are all V strings and the lower phase V strings have medium hanging strings All three phases are hanging strings  Crossarm with small folding arm Crossarm force: bending and torsion The cross-arm is a straight cross-arm force: bending 33.0^MThe overall height of the tower is 41.0^M 33.0^MThe overall height of the tower is 58.0^M

2. The working mechanism of the hanging string in the V string of the compact lower phase insulator of the present invention:

The double hoisting or anchor line V strings are not installed, and the load of the hoisting or anchor line is directly transmitted to the cross arm by temporary tools. After double hoisting, the V strings are all in a relaxed state.

Normally, the lower phase V-string is in a relaxed state, and the vertical load is borne by the middle-hanging string. For the horizontal load caused by strong wind, the wind from the left is borne by the left string of the V string, and the right string of the V string is slack; the wind coming from the right is borne by the right string of the V string, and the left string of the V string is slack. Regardless of the wind from the left, the wind from the right, or the longitudinal wind, two strings work and one string relaxes.

In special cases, the longitudinal load due to the tension difference will guide the insulator strings of the lower phase to shift to one side (along the direction of the resultant force line). When the lower phase V string shifts from the relaxed state to the tensioned state, the lower phase V string begins to share the vertical load borne by the middle hanging string, and the effect of the middle hanging string begins to decrease (the transition point of action may be called the critical point) . But at this time, the effect of the longitudinal load has not yet reached the desired deflection angle, and while continuing to deflect, the mid-hanging strings will gradually reduce from bearing all the vertical components until the deflection of the mid-hanging strings The rotation radius around the lifting point is restricted by the small rotation radius of the lower phase V string around the V string lifting point, and the rotation radius of the middle hanging string decreases with the increase of the deflection angle until the middle hanging string relaxes and completely exits the load-bearing state. At this time Only the V-string of the lower phase bears all the load. As the working state of the lower phase conductor tension difference that must be considered in the structural design, of course the lower phase V-string bears the entire load of the lower phase.

3. Analysis of the hyperstatic state of the lower phase three strings:

The three strings working together in the vertical plane is a hyperstatic state. From the above description of the working state of the combined strings under various working conditions, it can be seen that because the V strings in the lower phase are in a relaxed state, there is no situation where the three strings work together in the vertical plane under various working conditions. Only when the lower-phase insulator strings are guided by the longitudinal load of the tension difference, and the three strings shift to one side together, at the moment when the critical point is passed, the three lower-phase insulator strings share the entire load together, and the moment of this state is suspended. The role of the strings begins to decrease, and the V-strings of the lower phase begin to increase the force to be shared, neither of which is in the maximum state of its bearing capacity. At this moment only, since the action point of the resultant force has left the vertical plane of the three strings of hanging points in the lower phase, and the three forces are not in the same plane, it can establish the balance equation of the three-dimensional space, and solve the problem that the hanging points each share loads, rather than a statically indeterminate problem. But it is worth noting that its premise is that the lower phase V string must be in a relaxed state. This approach in theoretical analysis and engineering implementation has been tested by the test tower and the completed 500kV compact transmission line engineering practice, and has been in operation so far. works well.

4. The influence of the folding arm on the cross arm of the T-shaped tower on the torsion of the cross arm, and the aspects of resisting deformation of the whole tower:

Since the cross arm constituting the main part of the tower head in the present invention has folded arm structures at both ends, it has some influence on the torsion of the cross arm. Because a hanging point of the lower-phase V-string needs to be hung on the end of the small folding arm of the cross-arm, the cross-arm is twisted when the tension of the lower-phase conductor is different, just like the tower body of a conventional tower. It's just that this torsional load is only half of the tension difference of a phase conductor. As far as the current project is concerned, from the distribution analysis of the V-string force in the lower phase, it can be seen that when the longitudinal tension is 15%, the maximum longitudinal force acting on the folding arm is only 13647N. If the cross arm is regarded as a vertical tower body, the small folding arm is the cross arm protruding from the tower body. The torque on the tower is naturally resisted by the oblique materials on the tower body (that is, the oblique materials on the cross arm), and at the same time, the tower body is required to have enough anti-deformation diaphragms to keep its geometric system working normally.

At this point, the cross arm of the compact tower just meets these two requirements.

1) The cross arm of the compact tower has a fully enclosed oblique material network, which can transmit torque smoothly.

2) Due to the structure and the number of transverse partitions set up for the convenience of installation, operation and maintenance, there are as many as five within the length of 13.4m, and its ability to resist deformation is greatly enhanced.

It can be seen from the torsion calculation value of the cross-arm when the tension difference of the lower phase conductor is that the relative displacement of the edge of the cross-section of the cross-arm relative to the central axis is only 6mm, which will not affect the normal operation of the cross-arm.

In addition, the new T-shaped transmission tower scheme has passed the review of the relevant state departments, confirming that it meets the main technical requirements of the planned 500kV double-circuit compact line on the same tower, and solves the problem of building a 500kV double-circuit compact line on the same tower. The problem of the tower structure type of the line. It has carried out the real-type tower test of the straight tower and its matching corner tower, that is, the 500kV double-circuit double-circuit tower and a compact SCZ51 straight tower test tower test. On November 15, 2016, all 17 test conditions were successfully passed, including oblique wind overload of 160%. On November 29, 2001, the SCJ51 corner tower was officially launched for testing. By November 30, 2001, all 13 test conditions including high wind overload of 150% had passed successfully; its actual application is shown in Figure 3.

At present, the construction cost of 500kV double-circuit parallel transmission lines on the same tower in my country is relatively high, and the lightning resistance characteristics of 500kV double-circuit parallel transmission lines on the same tower are worse than those of single-circuit transmission lines. In order to reduce the construction cost of double-circuit parallel transmission lines on the same tower and improve Transmission capacity, improve lightning resistance level, especially in areas with dense transmission network, in limited corridors, apply the patented technology of the present invention to build double-circuit compact transmission lines on the same tower to solve large transmission capacity, reduce construction cost, and improve lightning resistance level preferred option.

As mentioned above, the present invention provides a better new power transmission tower structure and related applications, so an application for an invention patent is filed according to law; however, the above implementation description and drawings are the preferred embodiments of this creation, This is not intended to limit this creation, therefore, any similarity or similarity to the structure, device, and features of this creation should fall within the creation purpose of this creation and the scope of patent application.

Claims (4)

1, a kind of two-tower double-circuit compact linear power transmission iron tower, it includes body of the tower, tower head and lead, it is characterized in that: this tower head comprises an individual layer cross-arm, and it is symmetrically distributed in the body of the tower both sides, two return wires are arranged in the both sides of body of the tower, and this iron tower integral body is the T font structure;

A folding arm is extended at the both ends of this cross-arm respectively downwards; This wire arrangements mode is: arrange a loop three-phase conducting wire on the cross-arm of the both sides of body of the tower respectively, this three-phase conducting wire is compact arrangement and is triangularly arranged, wherein going up two phase conductors is placed on the cross-arm side by side, is two V-type strings, and following phase conductor is placed in the end and the body of the tower of this cross-arm folding arm, be a V-type insulator string, hung between the crosspoint of two-phase V-type string and this time phase conductor on this and hung string in one, this three-phase conducting wire V-type insulator string is arranged and is satisfied electric clearance requirement alternate and relatively simultaneously.

2, two-tower double-circuit compact linear power transmission iron tower as claimed in claim 1, wherein this time phase conductor V-type string is relaxed state, vertical load by in hang the string bear; During normal operation, remain two string work, a string lax in the three-phase conducting wire V-type string.

3, two-tower double-circuit compact linear power transmission iron tower as claimed in claim 1, wherein this three-phase conducting wire is formed a phase by 6 leads.

4, two-tower double-circuit compact linear power transmission iron tower as claimed in claim 1, wherein this iron tower height is between 40m-50m; Shared circuit corridor average out to 24m.

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