Method for reinforcing leg diagonal members of iron tower without power failure of power transmission line

Abstract

The invention provides a method for reinforcing an iron tower leg diagonal member without power failure of a power transmission line. The method comprises the following steps: S1, positioning an area which is seriously corroded and needs to be reinforced on leg diagonal members of an iron tower part or an area which needs to be reinforced by an owner; s2, short angle steel (1) is attached to the back face of the uncorroded intact diagonal member area in the area needing to be reinforced; s3, the short angle steel is connected to the inclined material through a filling plate (2) consistent with the length direction of the inclined material; s4, the short angle steel is connected to the inclined material in a reinforcing mode through flitch plates (3) consistent with the width direction of the inclined material; s5, firstly applying a pulling force capable of sharing the load of the iron tower at the area needing to be reinforced to the iron tower; replacing the bolts at the bottom of the corroded inclined material one by one; the iron tower leg diagonal member can be reinforced without power failure, the component stress area of the iron tower leg diagonal member can be increased, and the force transmission path of the iron tower leg diagonal member is optimized.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission lines, in particular to a method for reinforcing the oblique material of a leg of an iron tower of a power transmission line without power outage. Background Art

[0002] Some transmission line towers have been in operation for a long time and the terrain is relatively low. The components at the junction of the tower and the protective cap are easily buried or buried all year round. The soil is easily splashed onto the tower materials by rainwater to form a wrap around the tower materials. In particular, the layer of soil at the diagonal materials of the legs is prone to accumulate moisture and electrolytes and pollutants washed down from the top of the tower, forming a good corrosion system locally, causing the diagonal materials of the legs to corrode continuously. Since the cross-section of the components is weakened, the bearing capacity of the components is affected, thus posing a hidden danger to the safety of the tower.

[0003] The previous method of replacing rusted tower leg components was to cut off power, remove the old components, and then replace them with new materials. That is, after the tower processing plant processed the new tower materials to the site, it would cut off power and remove the line to eliminate the load effect of the ground wire on the tower. Then, the severely corroded leg diagonal components would be removed and replaced with new components, the tower would be reassembled, and the lines would be tightened again.

[0004] The previous treatment methods have the following disadvantages:

[0005] 1. The power outage lasts for a long time (about one month), causing great economic losses and affecting social life;

[0006] 2. Since most of the corroded rods are from old towers decades ago, they have been deformed due to long-term stress, which makes it easy for new components to be installed due to size and hole position deviations, making them impossible to install, affecting the progress of on-site construction.

[0007] In view of the previous method of dismantling old components and replacing them with new ones during power outages, the solution described in the present invention is based on the stress characteristics of the leg diagonal materials. A leg diagonal material reinforcement solution is developed to increase the stress area of ​​the leg diagonal materials and improve their force transmission path without the need for power outages, thereby avoiding the original rusted leg diagonal materials from affecting the overall safety of the iron tower and ensuring the stability of the power grid. This solution has been successfully applied in multiple power transmission line projects, with significant economic and social benefits. Summary of the invention

[0008] The present invention provides a method for reinforcing the oblique materials of the legs of an iron tower of a power transmission line without power outage. The oblique materials of the legs of an iron tower can be reinforced without power outage, and the stress-bearing area of ​​the components of the oblique materials of the legs of an iron tower can be increased and the force transmission path of the oblique materials of the legs of an iron tower can be optimized.

[0009] The present invention adopts the following technical solutions.

[0010] A method for reinforcing the oblique material of a tower leg of a power transmission line without power outage comprises the following steps;

[0011] Step S1, locating the area where the diagonal material of the legs of the tower is severely corroded and needs to be reinforced, or the area where the owner needs to be reinforced;

[0012] Step S2, attaching a short angle steel (1) to the back of the intact area of ​​the uncorroded oblique material in the area to be reinforced;

[0013] Step S3, connecting the short angle steel to the diagonal material with a filler plate (2) in the same length direction as the diagonal material;

[0014] Step S4, using a plate (3) that is consistent with the width direction of the diagonal material to reinforce and connect the short angle steel to the diagonal material;

[0015] Step S5: first apply a tensile force to the tower that can share the load of the tower in the area that needs to be reinforced; then replace the bottom bolts of the corroded diagonal material one by one.

[0016] In the method, the specification of the external auxiliary material is increased according to the actual reinforcement length of the reinforcement area, and the leg diagonal material of the reinforcement interval is modeled in the professional tower design software (such as smarttower) to calculate the bearing capacity according to the axial compression or axial tension member, and then the eccentric bearing capacity is calculated based on the eccentricity of the compression and bending members of the steel structure. The specific steps include software modeling, load input, program calculation, and verification according to the steel structure specification.

[0017] The professional tower design software is SmartTower, and the software modeling includes a rapid modeling step, a calculation data entry and correction step, and a result calculation and analysis step;

[0018] The operations in the rapid modeling step include creating absolute coordinate key points, creating body / leg connection tables, and quickly assembling towers using templates;

[0019] The operations in the calculation data entry and correction steps include modifying the constraint, minimum axis, parallel axis information, modifying the bar material information, adding wind pressure polygon data, and adding load and working condition combination data;

[0020] The operations in the result calculation and analysis steps include finite element analysis and verification, adjusting rod specifications, adding auxiliary balance method calculations, and outputting tower command diagrams and capital raising data.

[0021] When inputting loads, the loads on the tower are divided into line loads and tower body wind loads; line loads include conductor and ground wire loads;

[0022] The nodes where the facilities are loaded are the load application points; the load application points are divided into ground wire load nodes and tower body wind load nodes; at the nodes where the ground wire load is applied, the load components along the three coordinate axes are input, that is, according to the actual situation of the tower to be reinforced, by inputting the key information of horizontal span, vertical span, rotation angle, nominal height and ground wire parameters, the software performs load calculation and generates a load file.

[0023] When inputting loads, use the smartload software to generate a load file XX.ttt after the load calculation.

[0024] In the calculation of the program, the load calculation results are imported into the tower design software smarttower, and the result calculation and analysis are performed; the stress condition of a certain rod is judged by observing the stress ratio color and report of the components in the model.

[0025] When checking according to the steel structure specification, the original components of the reinforcement area and the inclined materials, short angle steels, filler plates and attached plates used for reinforcement are combined to form an integral compression-bending component, which is checked according to the steel structure design standards, specifically:

[0026] The calculation formula for the cross-sectional strength of compression-bending members is:

[0027]

[0028] Where: N——design value of axial pressure at the same section (N);

[0029] M x 、M x ——Design values ​​of bending moments about x-axis and y-axis at the same cross section (N·mm);

[0030] γ x , γ y ——The plastic development coefficient of the section is determined according to the internal force distribution of the compressed plate.

[0031] A n ——Net cross-sectional area of ​​the component (mm 2 );

[0032] W n ——Net section modulus of the component (mm 3 )

[0033] In step S1, the criterion for determining whether the diagonal material of a part of the tower leg is seriously corroded and needs to be reinforced is that the remaining thickness of the metal corrosion drops to less than 80% of the original specification size.

[0034] In step S5, a hoist is used to apply a pulling force to the tower to share the load of the tower at the area that needs to be reinforced.

[0035] The solution described in the present invention is based on the stress characteristics of the leg diagonal material, and proposes a leg diagonal material reinforcement solution that increases the stress area of ​​the leg diagonal material and improves its force transmission path without the need for power outage, thereby avoiding the original rusted leg diagonal material from affecting the overall safety of the iron tower and ensuring the stability of the power grid. This solution has been successfully applied in multiple power transmission line projects, with significant economic and social benefits.

[0036] The invention increases the area of ​​the reinforcement region by adding auxiliary materials at the diagonal materials of the iron tower legs, which can form an eccentric effect, so that the force transmission path of the iron tower is adjusted, and the effect of the force transmission path deviating from the corrosion zone can be formed, which is beneficial to the long-term use after reinforcement.

[0037] The method described in the present invention does not require power outage for construction. It only requires affixing short angle steels on the back of the original leg diagonal material to replace the bottom bolts of the corroded diagonal material one by one. The uncorroded intact area on the upper part of the diagonal material is connected to the back angle steel by filling plates and supplementing bolts. This reinforcement method can also increase the force-bearing area of ​​the component and optimize the force transmission path.

[0038] During the operation of the power grid, the leg diagonal materials of the existing transmission towers in low-lying areas are very susceptible to corrosion due to the alternating effects of dryness and wetness, thus posing a hidden danger to the safety of the towers. The conventional treatment method is to remove the old components during a power outage and then replace them with new ones, which results in long power outages and difficult installation of new components. In response to the pain points of conventional solutions, the present invention develops a leg diagonal material reinforcement solution that does not require power outages, increases the force-bearing area of ​​the tower leg diagonal materials, and improves their force transmission path. The solution has been successfully piloted and applied in actual projects, with significant economic and social benefits, and has been well received by the owners.

[0039] The technology of the present invention has good technical advantages for the expansion of technical transformation business of existing projects. Among them, the total length of 35 kV and above transmission lines of State Grid Fujian Company alone exceeds 5,700 kilometers, most of which are iron towers. The market potential for the application of this technology is relatively large. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0041] Attached Figure 1 It is a schematic diagram of the reinforcement diagonal material;

[0042] Attached Figure 2 It is a schematic diagram of the other direction of the reinforcement diagonal material;

[0043] Attached Figure 3 It is a schematic diagram of the short angle steel used for reinforcement;

[0044] Attached Figure 4 It is a schematic diagram of the reinforcing filler plate;

[0045] Attached Figure 5 It is a schematic diagram of a reinforcing plate;

[0046] Attached Figure 6 This is a schematic diagram of the actual photo of the site after reinforcement;

[0047] Attached Figure 7 It is a flowchart of the modeling and accounting steps;

[0048] In the figure: 1- short angle steel; 2- filling plate; 3- pasting plate. DETAILED DESCRIPTION

[0049] As shown in the figure, a method for reinforcing the oblique material of the leg of an iron tower of a power transmission line without power outage comprises the following steps;

[0050] Step S1, locating the area where the diagonal material of the legs of the tower is severely corroded and needs to be reinforced, or the area where the owner needs to be reinforced;

[0051] Step S2, attaching a short angle steel 1 to the back of the intact area of ​​the uncorroded oblique material in the area to be reinforced;

[0052] Step S3, connecting the short angle steel to the diagonal material with a filler plate 2 in the same length direction as the diagonal material;

[0053] Step S4, using a plate 3 that is consistent with the width direction of the diagonal material to reinforce and connect the short angle steel to the diagonal material;

[0054] Step S5: first apply a tensile force to the tower that can share the load of the tower in the area that needs to be reinforced; then replace the bottom bolts of the corroded diagonal material one by one.

[0055] In the method, the specification of the external auxiliary material is increased according to the actual reinforcement length of the reinforcement area, and the leg diagonal material of the reinforcement interval is modeled in the professional tower design software (such as smarttower) to calculate the bearing capacity according to the axial compression or axial tension member, and then the eccentric bearing capacity is calculated based on the eccentricity of the compression and bending members of the steel structure. The specific steps include software modeling, load input, program calculation, and verification according to the steel structure specification.

[0056] The professional tower design software is SmartTower, and the software modeling includes a rapid modeling step, a calculation data entry and correction step, and a result calculation and analysis step;

[0057] The operations in the rapid modeling step include creating absolute coordinate key points, creating body / leg connection tables, and quickly assembling towers using templates;

[0058] The operations in the calculation data entry and correction steps include modifying the constraint, minimum axis, parallel axis information, modifying the bar material information, adding wind pressure polygon data, and adding load and working condition combination data;

[0059] The operations in the result calculation and analysis steps include finite element analysis and verification, adjusting rod specifications, adding auxiliary balance method calculations, and outputting tower command diagrams and capital raising data.

[0060] When inputting loads, the loads on the tower are divided into line loads and tower body wind loads; line loads include conductor and ground wire loads;

[0061] The nodes where the facilities are loaded are the load application points; the load application points are divided into ground wire load nodes and tower body wind load nodes; at the nodes where the ground wire load is applied, the load components along the three coordinate axes are input, that is, according to the actual situation of the tower to be reinforced, by inputting the key information of horizontal span, vertical span, rotation angle, nominal height and ground wire parameters, the software performs load calculation and generates a load file.

[0062] When inputting loads, use the smartload software to generate a load file XX.ttt after the load calculation.

[0063] In the calculation of the program, the load calculation results are imported into the tower design software smarttower, and the result calculation and analysis are performed; the stress condition of a certain rod is judged by observing the stress ratio color and report of the components in the model.

[0064] When checking according to the steel structure specification, the original components of the reinforcement area and the inclined materials, short angle steels, filler plates and attached plates used for reinforcement are combined to form an integral compression-bending component, which is checked according to the steel structure design standards, specifically:

[0065] The calculation formula for the cross-sectional strength of compression-bending members is:

[0066]

[0067] Where: N——design value of axial pressure at the same section (N);

[0068] M x 、M y ——Design values ​​of bending moments about x-axis and y-axis at the same cross section (N·mm);

[0069] γ x , γ y ——The plastic development coefficient of the section is determined according to the internal force distribution of the compressed plate.

[0070] A n ——Net cross-sectional area of ​​the component (mm 2 );

[0071] W n ——Net section modulus of the component (mm 3 ).

[0072] In step S1, the criterion for determining whether the diagonal material of a part of the tower leg is seriously corroded and needs to be reinforced is that the remaining thickness of the metal corrosion drops to less than 80% of the original specification size.

[0073] In step S5, a hoist is used to apply a pulling force to the tower to share the load of the tower at the area that needs to be reinforced.

Claims

1. A method for reinforcing the oblique material of the legs of an iron tower of a power transmission line without power outage, characterized in that: The steps include: Step S1, locating the area where the diagonal material of the legs of the tower is severely corroded and needs to be reinforced, or the area where the owner needs to be reinforced; Step S2, attaching a short angle steel (1) to the back of the intact area of ​​the uncorroded oblique material in the area to be reinforced; Step S3, connecting the short angle steel to the diagonal material with a filler plate (2) in the same length direction as the diagonal material; Step S4, using a plate (3) that is consistent with the width direction of the diagonal material to reinforce and connect the short angle steel to the diagonal material; Step S5: first apply a tensile force to the tower that can share the load of the tower in the area that needs to be reinforced; then replace the bottom bolts of the corroded diagonal material one by one.

2. The method for reinforcing the leg oblique material of an iron tower of a power transmission line without power outage according to claim 1, characterized in that: In the method, the specification of the external auxiliary material is increased according to the actual reinforcement length of the reinforcement area, and the leg diagonal material of the reinforcement interval is modeled in the professional tower design software to calculate the bearing capacity according to the axial compression or axial tension component, and then the eccentric bearing capacity is calculated based on the eccentricity of the compression and bending components of the steel structure. The specific steps include software modeling, load input, program calculation, and verification according to the steel structure specification.

3. The method for reinforcing the leg oblique material of an iron tower of a power transmission line without power outage according to claim 2, characterized in that: The professional tower design software is SmartTower, and the software modeling includes a rapid modeling step, a calculation data entry and correction step, and a result calculation and analysis step; The operations in the rapid modeling step include creating absolute coordinate key points, creating body / leg connection tables, and quickly assembling towers using templates; The operations in the calculation data entry and correction steps include modifying the constraint, minimum axis, parallel axis information, modifying the bar material information, adding wind pressure polygon data, and adding load and working condition combination data; The operations in the result calculation and analysis steps include finite element analysis and verification, adjusting rod specifications, adding auxiliary balance method calculations, and outputting tower command diagrams and capital raising data.

4. The method for reinforcing the leg oblique material of a power transmission line without power outage according to claim 2, characterized in that: When inputting loads, the loads on the tower are divided into line loads and tower body wind loads; line loads include conductor and ground wire loads; The nodes where the facilities are loaded are the load application points; the load application points are divided into ground wire load nodes and tower body wind load nodes; at the nodes where the ground wire load is applied, the load components along the three coordinate axes are input, that is, according to the actual situation of the tower to be reinforced, by inputting the key information of horizontal span, vertical span, rotation angle, nominal height and ground wire parameters, the software performs load calculation and generates a load file.

5. The method for reinforcing the leg oblique material of a power transmission line without power outage according to claim 4, characterized in that: When inputting loads, use the smartload software to generate a load file XX.ttt after the load calculation.

6. The method for reinforcing the leg oblique material of a power transmission line without power outage according to claim 4, characterized in that: In the calculation of the program, the load calculation results are imported into the tower design software smarttower, and the result calculation and analysis are performed; the stress condition of a certain rod is judged by observing the stress ratio color and report of the components in the model.

7. The method for reinforcing the leg oblique material of a power transmission line without power outage according to claim 4, characterized in that: When checking according to the steel structure specification, the original components of the reinforcement area and the inclined materials, short angle steels, filler plates and attached plates used for reinforcement are combined to form an integral compression-bending component, which is checked according to the steel structure design standards, specifically: The calculation formula for the cross-sectional strength of compression-bending members is: Where: N - the design value of axial pressure at the same section (N); M x 、M y --Design values ​​of bending moments about x-axis and y-axis at the same section (N·mm); γ x , γ y - Section plastic development coefficient, according to the internal force distribution of the compressed plate, determine the width-to-thickness ratio of the section plate. A n - Net cross-sectional area of ​​the component (mm 2 ); W n - Net section modulus of the component (mm 3 ).

8. The method for reinforcing the leg oblique material of a power transmission line without power outage according to claim 1, characterized in that: In step S1, the criterion for determining whether the diagonal material of a part of the tower leg is seriously corroded and needs to be reinforced is that the remaining thickness of the metal corrosion drops to less than 80% of the original specification size.

9. The method for reinforcing the leg oblique material of a power transmission line without power outage according to claim 1, characterized in that: In step S5, a hoist is used to apply a pulling force to the tower to share the load of the tower at the area that needs to be reinforced.

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