A load combination design method for AC / DC hybrid tension transmission towers in light ice areas

Abstract

The present invention provides a load combination design method for AC / DC mixed-voltage tension transmission towers in light ice areas. The method takes into account the complex stress conditions of the tension transmission towers, analyzes the load conditions of the tension transmission towers under five conditions: normal operation, ice-covered operation, installation and construction, line breakage and uneven ice coverage, and calculates the node loads of the lines on the front and rear sides of the tower under 68 calculation conditions. According to the calculation results, the internal forces of the tower components or connection nodes can be analyzed, thereby designing the tower structure and selecting appropriate tower components, so that the tension towers can meet the load capacity under different conditions, improve the reliability of the towers, and meet the safety and stability requirements of the power grid.

Description

Technical Field

[0001] The invention relates to the technical field of load design of AC / DC mixed-voltage transmission towers, and in particular to a load combination design method for AC / DC mixed-voltage tension transmission towers in light ice areas. Background Art

[0002] my country's high-voltage transmission lines are long and span a wide area, passing through various complex geological and geomorphic areas. The factors that affect the design of the foundation of high-voltage transmission line towers include geological conditions, load characteristics, bearing characteristics of the foundation and foundation, construction methods, etc. Among them, the light ice area is a typical wire-laying environment, so it is necessary to design the load of the light ice area transmission tower. As a type of transmission tower, the tension tower refers to a tower that not only supports the gravity and wind force of the conductor and overhead ground wire, but also bears the tension of these lines. The conductor and overhead ground wire are disconnected at the tension tower and are positioned in the straight line segment of the conductor and overhead ground wire to reduce the length of the continuous gear along the longitudinal direction of the line, so as to facilitate the construction and maintenance of the line, and control the range of possible stringing of the tower along the longitudinal direction of the line. The tension tower is divided into tension straight line tower, tension corner tower and terminal tower.

[0003] In the existing design methods, only the load combination design for single-circuit DC erection or AC-only erection is given, while the load combination design for AC / DC mixed-voltage tension transmission towers is still in a blank stage and lacks corresponding technical guidance. Since the lines of the tension tower are directly hung on the front and rear sides of the tower body through hardware, there is a certain angle between the front and rear lines. The load combination form under different working conditions during AC / DC mixed-voltage erection is more complicated. If the load of the AC / DC mixed-voltage tension transmission tower is not effectively designed, there will be certain safety hazards, which may easily cause safety accidents and affect the stable operation of the transmission line. Summary of the invention

[0004] The present invention aims to at least solve one of the technical problems in the prior art that the load combination of AC / DC mixed-voltage tension towers is complex, the design of load combination of AC / DC mixed-voltage tension transmission towers in light ice areas is in a blank stage, there is a lack of corresponding technical guidance, the existing design methods are difficult to meet actual operation requirements, there are safety hazards, and safety accidents are prone to occur.

[0005] To this end, the present invention provides a load combination design method for an AC / DC mixed-voltage tension transmission tower in a light ice zone.

[0006] The present invention provides a load combination design method for an AC / DC mixed-voltage tension transmission tower in a light ice area, wherein the tension transmission tower comprises an iron tower and a wire, wherein the wire comprises a ground wire portion, a DC conductor portion, and an AC conductor portion arranged on the iron tower, and the wire is arranged at a certain angle to the advancing direction of the tension transmission tower, and the method comprises the following steps:

[0007] S1. The front and rear vertical loads of the designed tension transmission tower are different combinations of downward pressure vertical loads or upward pull vertical loads. Considering the tension at the front and rear of the transmission tower, calculate the node loads of the line on the tower in all directions under different wind direction angles and at the maximum or minimum rotation angle under normal operation;

[0008] S2. Design the vertical loads on the front and rear sides of the tension transmission tower as different combinations of downward pressure vertical loads or upward pull vertical loads, taking into account the tension on the front and rear sides of the transmission tower, and calculate the node loads on the tower in all directions under different wind direction angles and after taking the maximum or minimum rotation angle when operating under icing conditions;

[0009] S3. Under the conditions that the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, and the rear tension is less than the standard value, calculate the node loads of the line on the tower in all directions when the maximum or minimum rotation angle is taken under the installation condition; the installation condition includes the hoisting process and the anchor line process;

[0010] S4. Consider the maximum bending moment and maximum torsion, and calculate the node loads of the lines on the tower in all directions when any two lines are broken and a fault occurs in the absence of wind, using the maximum rotation angle or the minimum rotation angle;

[0011] S5. Under the conditions of maximum bending moment and maximum vertical load, the vertical load properties of the front and rear vertical loads of the tension transmission tower are considered, and the node loads of the lines on the tower in all directions at different wind angles under uneven icing are calculated using the maximum rotation angle or the minimum rotation angle.

[0012] A load combination design method for AC / DC hybrid tension transmission tower in light ice area according to the above technical solution of the present invention may also have the following additional technical features:

[0013] In the above technical solution, a calculation coordinate system is specified, wherein the X-axis direction is the horizontal crossarm direction, the Y-axis direction is perpendicular to the horizontal crossarm direction, and the Z-axis direction is the vertical direction perpendicular to the XY plane.

[0014] In the above technical solution, S1 includes the single-circuit operation of the DC line and the simultaneous operation of the AC and DC lines. The calculation is performed at wind direction angles of 90 degrees and 0 degrees. Under normal operation, the following calculation conditions are included:

[0015] At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0016] At the maximum turning angle, the wind direction angle is 90 degrees. The front and rear vertical loads of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The AC and DC lines are running at the same time.

[0017] Maximum rotation angle, wind direction angle is 90 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0018] At the maximum turning angle, the wind direction angle is 90 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower is less than the standard value, and the AC and DC lines are running at the same time;

[0019] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0020] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the AC and DC lines are running at the same time;

[0021] Minimum rotation angle, wind direction angle is 0 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0022] Minimum rotation angle, wind direction angle is 0 degrees, the vertical load on the front side of the tension transmission tower is 0, the vertical load on the rear side is the upward vertical load, the tension on the front and rear sides of the tension transmission tower are both less than the standard value, and the AC and DC lines are running at the same time;

[0023] At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the DC line is in single-circuit operation;

[0024] Maximum turning angle, wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the DC line is in single-circuit operation;

[0025] Minimum turning angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the DC line is in single-circuit operation;

[0026] At the minimum turning angle, the wind direction angle is 0 degrees. The vertical load on the front and rear sides of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The DC line operates in a single loop.

[0027] In the above technical solution, the node loads of the lines on the front and rear sides of the tower under normal operation are calculated in the X-axis direction, the Y-axis direction and the Z-axis direction respectively. The calculation method is as follows:

[0028]

[0029]

[0030] When the load is downward:

[0031]

[0032] When pulling up the load:

[0033]

[0034] in, is the structural importance coefficient, which is 1.1 for UHV lines and 1.0 for general lines; is the permanent load partial factor, which is 1.2 for transmission lines; is the variable load combination factor, which is taken as 1.4 for transmission lines; is the variable load combination coefficient for operating conditions, 1.0 for normal and icing conditions, and 0.9 for installation, disconnection, and uneven icing; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load;

[0035] It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire); The Y-direction tension of the wires on one side (ground wire, DC wire, AC wire); The Z line on one side (ground wire, DC wire, AC wire) is pressed downward. The Z-upward vertical load of the lines on one side (ground wire, DC conductor, AC conductor) is considered as a live load.

[0036] In the above technical solution, when calculating the icing operation, the node loads of the lines on the tower in all directions include the following calculation conditions:

[0037] At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0038] At the maximum turning angle, the wind direction angle is 90 degrees. The front and rear vertical loads of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The AC and DC lines are running at the same time.

[0039] Maximum rotation angle, wind direction angle is 90 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0040] At the maximum turning angle, the wind direction angle is 90 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower is less than the standard value, and the AC and DC lines are running at the same time;

[0041] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0042] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the AC and DC lines are running at the same time;

[0043] Minimum rotation angle, wind direction angle is 0 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0044] At the minimum turning angle, the wind direction angle is 0 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower are both less than the standard value, and the AC and DC lines operate simultaneously.

[0045] In the above technical solution, the node loads of the lines on the front and rear sides of the tower under ice-covered operation are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0046]

[0047]

[0048] When the load is downward:

[0049]

[0050] When pulling up the load:

[0051]

[0052] in, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) under ice-covered condition; It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when ice is applied; It is the downward pressure load on the lines (ground wire, DC wire, AC wire) when covered with ice.

[0053] In the above technical solution, the hoisting process needs to verify the stress of the local components of the tower, hoist the DC conductor V string through the hanging point of the DC cross arm, and then hoist the three-phase AC conductor I string step by step from left to right and from top to bottom. The hoisting process includes the following calculation conditions:

[0054] At the maximum turning angle, the wind direction angle is 90 degrees, the Z-JL jumper string is hoisted, and the other conductors are not hoisted;

[0055] At the maximum turning angle, the wind direction angle is 90 degrees, the Z-JR jumper string is hoisted, and the other conductors are not hoisted;

[0056] At the maximum turning angle, the wind direction angle is 90 degrees, the J-JU jumper string is hoisted, and the other conductors are not hoisted;

[0057] At the maximum turning angle, the wind direction angle is 90 degrees, the J-JL jumper string is hoisted, and the other conductors are not hoisted;

[0058] At the maximum turning angle, the wind direction angle is 90 degrees, the J-JR jumper string is hoisted, and the other conductors are not hoisted;

[0059] Minimum turning angle, wind direction angle is 90 degrees, Z-JL jumper string is hoisted, and other conductors are not hoisted;

[0060] Minimum turning angle, wind direction angle is 90 degrees, Z-JR jumper string is hoisted, and other conductors are not hoisted;

[0061] Minimum turning angle, wind direction angle is 90 degrees, J-JU jumper string is hoisted, and other conductors are not hoisted;

[0062] Minimum turning angle, wind direction angle is 90 degrees, J-JL jumper string is hoisted, and other conductors are not hoisted;

[0063] Minimum turning angle, wind direction angle is 90 degrees, J-JR jumper string is hoisted, and other conductors are not hoisted.

[0064] In the above technical solution, the node loads of the wire on the front and rear sides of the tower during the hoisting process are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0065]

[0066]

[0067] Load of hoisting jumper string:

[0068]

[0069] In the formula, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) when hoisted; It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when it is hoisted; It is the vertical load in Z direction of the jumper string of lines (ground wire, DC wire, AC wire) when hoisted; is the installation dynamic coefficient, which is taken as 1.1; is the lifting coefficient, take 2.0; It is the additional load for hoisting, and the value is taken according to the specification;

[0070] All loads on the unlifted parts are 0.

[0071] In the above technical solution, in the anchoring process, the left and right ground wires are anchored first, and then the DC conductor or AC conductor is anchored in the order from right to left and from top to bottom. When the front side of the tension transmission tower is anchored, the load on the rear side is 0, and the design is carried out according to the longitudinal bending and transverse bending. The node loads of the line on the tower in various directions at different anchoring progress during the anchoring process are calculated with the maximum rotation angle or the minimum rotation angle, including the following calculation conditions:

[0072] Minimum turning angle, wind direction angle is 90 degrees, DL is on the anchor line, and the rest are not anchored;

[0073] Minimum turning angle, wind direction angle is 90 degrees, DL is anchored, DR is on the anchor line, and the rest are not anchored;

[0074] Minimum turning angle, wind direction angle is 90 degrees, ground line is anchored, Z-JL is on the anchor line, and the rest are not anchored;

[0075] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL are anchored, J-JU is on the anchor line, and the rest are not anchored;

[0076] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU are anchored, J-JL is on the anchor line, and the rest are not anchored;

[0077] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU, J-JL are anchored, Z-ZR is on the anchor line, and the rest are not anchored;

[0078] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU, J-JL, Z-ZR are anchored, J-JR is anchoring;

[0079] At the maximum turning angle, the wind direction angle is 90 degrees, DL is on the anchor line, and the rest are not anchored;

[0080] At the maximum turning angle, the wind direction angle is 90 degrees, DL is anchored, DR is on the anchor line, and the rest are not anchored;

[0081] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line is anchored, Z-JL is on the anchor line, and the rest are not anchored;

[0082] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line and Z-JL are anchored, J-JU is on the anchor line, and the rest are not anchored;

[0083] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line, Z-JL, and J-JU are anchored, J-JL is on the anchor line, and the rest are not anchored;

[0084] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line, Z-JL, J-JU, and J-JL are anchored, Z-ZR is on the anchor line, and the rest are not anchored;

[0085] At the maximum turning angle, the wind direction angle is 90 degrees. The ground line, Z-JL, J-JU, J-JL, and Z-ZR are anchored, and J-JR is anchoring.

[0086] In the above technical solution, the node loads of the anchor line on the front and rear sides of the tower are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0087]

[0088] Anchor line section:

[0089]

[0090]

[0091] Anchored part:

[0092]

[0093]

[0094] in, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) under the anchor line condition; It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when it is hoisted; It is the tension of temporary wires on one side (ground wire, DC conductor, AC conductor) when the wire is anchored, and the value is determined by referring to the tower load specification; To calculate the traction coefficient according to the line, take the interval of 1.05~1.15; The angle between the temporary cable and the ground is 45°;

[0095] All loads on the unanchored parts are 0.

[0096] In the above technical scheme, the line is broken according to the tension of the front side of the tension transmission tower is greater than the standard value, the tension of the rear side is less than the standard value, and both the front and rear sides are considered as downward pressure sag loads. The maximum or minimum rotation angle is used to calculate the node loads of the line on the tower in all directions when any two lines are broken in the windless condition, including the following calculation conditions:

[0097] Maximum turning angle / minimum turning angle, cut off at DL and Z-JL;

[0098] Maximum turning angle / minimum turning angle, breaking DL and J-JL;

[0099] Maximum turning angle / minimum turning angle, cut off at DR and Z-JR;

[0100] Maximum turning angle / minimum turning angle, cut off at DR and J-JR;

[0101] Maximum turning angle / minimum turning angle, cut off at J-JL and J-JR;

[0102] Maximum turning angle / minimum turning angle, cut at Z-JL and J-JL;

[0103] Maximum turning angle / minimum turning angle, breaking at Z-JR and J-JR;

[0104] Maximum turning angle / minimum turning angle, break at Z-JR and J-ZU;

[0105] Maximum turning angle / minimum turning angle, break at J-ZU and J-JR.

[0106] In the above technical solution, the node loads of the wire on the front and rear sides of the tower are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively when the wire breaks and causes a fault. The calculation method is as follows:

[0107]

[0108]

[0109]

[0110] in, It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when the wire is broken; It is the Z-direction vertical load of the line (ground wire, DC wire, AC wire) when it is broken.

[0111] In the above technical solution, the vertical load properties include downward pressure vertical load and upward pull vertical load, and the wind direction angles of 90 degrees and 0 degrees are selected. At the same time, the simultaneous operation of AC and DC lines and the single-circuit operation of DC lines are considered. The node loads of the lines on the towers in various directions at different wind direction angles under uneven icing are calculated at the maximum rotation angle or the minimum rotation angle, including the following calculation conditions:

[0112] Maximum turning angle, wind direction angle is 90 degrees, maximum bending moment, AC and DC lines are running simultaneously;

[0113] Maximum turning angle, wind direction angle is 90 degrees, maximum bending moment, single-circuit operation of DC line;

[0114] Maximum rotation angle, wind direction angle is 90 degrees, maximum bending moment, one side of the front and rear side vertical loads of the tension transmission tower is downward pressure vertical load, the other side is upward pull vertical load, AC and DC lines are running at the same time;

[0115] Minimum turning angle, wind direction angle is 0 degrees, maximum bending moment, AC and DC lines are running simultaneously;

[0116] Minimum turning angle, wind direction angle is 0 degrees, maximum bending moment, single-circuit operation of DC line;

[0117] Minimum turning angle, wind direction angle of 0 degrees, maximum bending moment, one side of the front and rear side vertical loads of the tension transmission tower is a downward pressure vertical load, and the other side is an upward pull vertical load, and the AC and DC lines are running simultaneously.

[0118] In the above technical solution, the node loads of the lines on the front and rear sides of the tower under uneven ice coverage are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0119]

[0120]

[0121] When the load is downward:

[0122]

[0123] When pulling up the load:

[0124]

[0125] In the formula, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) under the condition of uneven ice; It is the Y-direction tension of the lines (ground wire, DC wire, AC wire) on one side under uneven ice conditions; It is the downward pressure load on the lines (ground wire, DC wire, AC wire) under uneven ice conditions.

[0126] In summary, due to the adoption of the above technical features, the beneficial effects of the present invention are:

[0127] A load combination design method for AC / DC mixed-voltage tension transmission towers in light ice areas is provided. The complex stress conditions of the tension transmission towers are considered, and the load conditions of the tension transmission towers are analyzed under five conditions: normal operation, ice-covered operation, installation and construction, line breakage and uneven ice coverage. The node loads of the lines on the front and rear sides of the tower are calculated under 68 calculation conditions. According to the calculation results, the internal forces of the tower components or connection nodes can be analyzed, so as to design the tower structure and select suitable tower components, so that the tension tower can meet the load capacity under different conditions, improve the reliability of the tower, and meet the safety and stability requirements of the power grid.

[0128] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0129] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0130] Figure 1 It is a flowchart of a load combination design method for AC / DC mixed-voltage tension transmission tower in a light ice zone according to an embodiment of the present invention;

[0131] Figure 2 It is a structural schematic diagram of a tension transmission tower in a load combination design method for an AC / DC mixed-voltage tension transmission tower in a light ice zone according to an embodiment of the present invention;

[0132] Figure 3 The present invention is a top view of a tension transmission tower according to a load combination design method for an AC / DC mixed-voltage tension transmission tower in a light ice zone according to an embodiment of the present invention. DETAILED DESCRIPTION

[0133] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0134] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0135] Refer to the following Figures 1 to 3 A load combination design method for AC / DC mixed-voltage tension transmission towers in light ice areas is described in detail according to some embodiments of the present invention.

[0136] Some embodiments of the present application provide a load combination design method for an AC / DC mixed-voltage tension transmission tower in a light ice zone.

[0137] like Figures 1 to 3 As shown, the first embodiment of the present invention proposes a load combination design method for AC / DC mixed-voltage tension transmission towers in light ice areas, wherein the tension transmission tower comprises an iron tower and wires, wherein the wires comprise a ground wire portion, a DC conductor portion, and an AC conductor portion arranged on the iron tower; the wires from the front or rear side of the tension transmission tower are arranged at a certain angle to the forward direction of the tension transmission tower, and the forward direction of the tension transmission tower is usually perpendicular to the horizontal cross arm of the tension transmission tower, and the angle is α, which is in the range of 0 to 45°. Figure 2 and Figure 3 As shown, in the tension transmission tower, the wires are erected on the tower, and the ground wire part includes a ground wire crossarm, a ground wire tension string and a ground wire, wherein DL represents the left ground wire and DR represents the right ground wire; the DC conductor part includes a DC conductor crossarm, a DC V jumper string and a DC conductor, wherein Z-JL represents the left-pole DC conductor and Z-JR represents the right-pole DC conductor; the AC conductor part includes an AC conductor crossarm, an AC I jumper string and an AC conductor, wherein J-JU represents the upper-phase AC conductor, J-JL represents the left-phase AC conductor and J-JR represents the right-phase AC conductor.

[0138] The method comprises the following steps:

[0139] S1. The front and rear vertical loads of the designed tension transmission tower are different combinations of downward pressure vertical loads or upward pull vertical loads, taking into account the tension at the front and rear of the transmission tower, that is, whether the tension at the front or rear of the transmission tower exceeds the standard value. The difference in tension is caused by the difference in the front and rear spans of the tension tower. The standard value refers to the value used to measure the tension. The tension greater than the standard value is regarded as a large tension, and the tension less than the standard value is regarded as a small tension, the same below; calculate the node loads of the line on the tower in all directions under different wind direction angles and after taking the maximum or minimum rotation angle under normal operation;

[0140] S2. Design the vertical loads on the front and rear sides of the tension transmission tower as different combinations of downward pressure vertical loads or upward pull vertical loads, taking into account the tension on the front and rear sides of the transmission tower, and calculate the node loads on the tower in all directions under different wind direction angles and after taking the maximum or minimum rotation angle when operating under icing conditions;

[0141] S3. Under the conditions that the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, and the rear tension is less than the standard value, calculate the node loads of the line on the tower in all directions when the maximum or minimum rotation angle is taken under the installation condition; the installation condition includes the hoisting process and the anchor line process;

[0142] S4. Consider the maximum bending moment and maximum torsion, and calculate the node loads of the lines on the tower in all directions when any two lines are broken and a fault occurs in the absence of wind, using the maximum rotation angle or the minimum rotation angle;

[0143] S5. Under the conditions of maximum bending moment and maximum vertical load, the vertical load properties of the front and rear vertical loads of the tension transmission tower are considered, and the node loads of the line on the tower in all directions at different wind direction angles under uneven icing are calculated at the maximum or minimum rotation angle;

[0144] S6. Load the node load on the structural action point and design the transmission tower structural components and nodes using general design software.

[0145] A calculation coordinate system is specified, where the X-axis direction is the horizontal crossarm direction, the Y-axis direction is perpendicular to the horizontal crossarm direction, and the Z-axis direction is the vertical direction perpendicular to the XY plane.

[0146] Design various load forms for the tension tower under different conditions, calculate the node loads of the lines on the front and rear sides of the tension tower under different load forms, and after obtaining the node loads, design the tower components and tower nodes to improve the load capacity of the tower so that the tower meets the load requirements in actual operation conditions; after obtaining the node loads, the design of the tower components and tower nodes can be completed by inputting the node loads into existing design methods or design software. Therefore, the focus of this embodiment is on how to obtain the load conditions that the tension transmission tower may bear when it is erected in a light ice area with AC / DC mixed pressure, and no requirements are made on the design of the tower structure after obtaining the load conditions.

[0147] It should be noted that in this manual:

[0148] The maximum bending moment should be understood as the maximum longitudinal or transverse bending moment that the tower is subjected to;

[0149] The maximum / minimum turning angle should be understood as the maximum / minimum angle between the front and rear lines of the tower under the planned use conditions;

[0150] The maximum / minimum vertical load should be understood as the vertical load on the conductor that the tower bears at the maximum / minimum planned vertical span;

[0151] The uplift load should be understood as the upward uplift force of the load on the tension tower;

[0152] Downward pressure load should be understood as the downward pressure of the load on the tension tower;

[0153] The wind direction angle is the angle between the wind direction and the axis of the line;

[0154] The front and rear sides of the tension tower are as follows Figure 3 shown.

[0155] The second embodiment of the present invention proposes a load combination design method for AC / DC mixed voltage tension transmission tower in light ice area, and based on the first embodiment, as Figures 1 to 3 As shown in the figure, when designing normal operation, both DC and AC are running at the same time. Since the conductors are hung on the front and rear sides of the tension tower respectively, the spacing of the front and rear lines is generally different during design. At this time, the lateral wind load (X direction) along the crossarm, the longitudinal direction (Y direction) along the conductor, and the vertical load (Z direction) on the front and rear sides are all different. The wind load is 90° for the parallel crossarm. In addition, there is an angle between the front and rear lines of the tower under the planned use conditions, which is the rotation angle. The rotation angle generally has an angle range during design, such as 0~10°. At this time, the maximum rotation angle is 10° and the minimum rotation angle is 0°. Considering that DC and AC are not a system, single-circuit operation can exist. Considering that DC is more important, the single-circuit operation of the ground wire and DC part should be selected.

[0156] Therefore, S1 includes the single-circuit operation of the DC line and the simultaneous operation of the AC and DC lines. The calculation is performed at wind direction angles of 90 degrees and 0 degrees. Under normal operation, it includes the following 12 calculation conditions:

[0157] At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0158] At the maximum turning angle, the wind direction angle is 90 degrees. The front and rear vertical loads of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The AC and DC lines are running at the same time.

[0159] Maximum rotation angle, wind direction angle is 90 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0160] At the maximum turning angle, the wind direction angle is 90 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower is less than the standard value, and the AC and DC lines are running at the same time;

[0161] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0162] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the AC and DC lines are running at the same time;

[0163] Minimum rotation angle, wind direction angle is 0 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0164] Minimum rotation angle, wind direction angle is 0 degrees, the vertical load on the front side of the tension transmission tower is 0, the vertical load on the rear side is the upward vertical load, the tension on the front and rear sides of the tension transmission tower are both less than the standard value, and the AC and DC lines are running at the same time;

[0165] At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the DC line is in single-circuit operation;

[0166] Maximum turning angle, wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the DC line is in single-circuit operation;

[0167] Minimum turning angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the DC line is in single-circuit operation;

[0168] At the minimum turning angle, the wind direction angle is 0 degrees. The vertical load on the front and rear sides of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The DC line operates in a single loop.

[0169] Under 12 calculation conditions, the node loads of the lines on the front and rear sides of the tower under normal operation are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0170]

[0171]

[0172] When the load is downward:

[0173]

[0174] When pulling up the load:

[0175]

[0176] in, is the structural importance coefficient, which is 1.1 for UHV lines and 1.0 for general lines; is the permanent load partial factor, which is 1.2 for transmission lines; is the variable load combination factor, which is taken as 1.4 for transmission lines; is the variable load combination coefficient for operating conditions, 1.0 for normal and icing conditions, and 0.9 for installation, disconnection, and uneven icing; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; and The values ​​are shown in the following table:

[0177]

[0178] It is the X-direction wind load of one side of the line (ground wire, DC conductor, AC conductor). Here, "one side" refers to the front side or the rear side of the tension transmission tower, the same below; The Y-direction tension of the wires on one side (ground wire, DC wire, AC wire); The Z line on one side (ground wire, DC wire, AC wire) is pressed downward. The Z-upward vertical load of the wires on one side (ground wire, DC wire, AC wire) is considered as a live load; , , , Under the known conditions, the node loads of the lines on the front and rear sides of the tension tower can be calculated using the above formula, thus realizing the design.

[0179] After obtaining the node loads of the lines on the front and rear sides of the tower in the X-axis direction, Y-axis direction and Z-axis direction under different calculation conditions, the tower components / connection points can be designed for the node loads under different calculation conditions, and the most suitable components that meet the requirements of all scenarios can be selected. The node loads obtained under other conditions (such as uneven icing and broken wire failure) can also be used to design subsequent tower components / connection points using the above method.

[0180] The third embodiment of the present invention proposes a load combination design method for AC / DC hybrid tension transmission towers in light ice areas, and based on any of the above embodiments, Figures 1 to 3 As shown in the figure, when calculating the icing operation, the node loads of the lines on the tower in all directions include the following 8 calculation conditions:

[0181] At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0182] At the maximum turning angle, the wind direction angle is 90 degrees. The front and rear vertical loads of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The AC and DC lines are running at the same time.

[0183] Maximum rotation angle, wind direction angle is 90 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0184] At the maximum turning angle, the wind direction angle is 90 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower is less than the standard value, and the AC and DC lines are running at the same time;

[0185] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time;

[0186] Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the AC and DC lines are running at the same time;

[0187] Minimum rotation angle, wind direction angle is 0 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time;

[0188] At the minimum turning angle, the wind direction angle is 0 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower are both less than the standard value, and the AC and DC lines operate simultaneously.

[0189] Under 8 calculation conditions, the node loads of the lines on the front and rear sides of the tower under ice-covered operation are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0190]

[0191]

[0192] When the load is downward:

[0193]

[0194] When pulling up the load:

[0195]

[0196] in, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) under ice-covered condition; It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when ice is applied; It is the downward pressure load on the lines (ground wire, DC wire, AC wire) when covered with ice.

[0197] The fourth embodiment of the present invention proposes a load combination design method for AC / DC mixed voltage tension transmission tower in light ice area, and based on any of the above embodiments, as Figures 1 to 3 As shown, the hoisting process needs to verify the stress of the local components of the tower. Considering that the wind direction angle is 90 degrees, the front and rear sides of the tension tower are both downward pressure loads, the tension on the front side is greater than the standard value, and the tension on the rear side is less than the standard value. In the hoisting process, the DC conductor V string is hoisted through the hanging point of the DC cross arm, and then the three-phase AC conductor I string is hoisted step by step from left to right and from top to bottom. Under the hoisting process, the following 10 calculation conditions are included:

[0198] At the maximum turning angle, the wind direction angle is 90 degrees, the Z-JL jumper string is hoisted, and the other conductors are not hoisted;

[0199] At the maximum turning angle, the wind direction angle is 90 degrees, the Z-JR jumper string is hoisted, and the other conductors are not hoisted;

[0200] At the maximum turning angle, the wind direction angle is 90 degrees, the J-JU jumper string is hoisted, and the other conductors are not hoisted;

[0201] At the maximum turning angle, the wind direction angle is 90 degrees, the J-JL jumper string is hoisted, and the other conductors are not hoisted;

[0202] At the maximum turning angle, the wind direction angle is 90 degrees, the J-JR jumper string is hoisted, and the other conductors are not hoisted;

[0203] Minimum turning angle, wind direction angle is 90 degrees, Z-JL jumper string is hoisted, and other conductors are not hoisted;

[0204] Minimum turning angle, wind direction angle is 90 degrees, Z-JR jumper string is hoisted, and other conductors are not hoisted;

[0205] Minimum turning angle, wind direction angle is 90 degrees, J-JU jumper string is hoisted, and other conductors are not hoisted;

[0206] Minimum turning angle, wind direction angle is 90 degrees, J-JL jumper string is hoisted, and other conductors are not hoisted;

[0207] Minimum turning angle, wind direction angle is 90 degrees, J-JR jumper string is hoisted, and other conductors are not hoisted.

[0208] Under 10 calculation conditions, the node loads of the lines on the front and rear sides of the tower during the hoisting process are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0209]

[0210]

[0211] Load of hoisting jumper string:

[0212]

[0213] In the formula, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) when hoisted; It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when it is hoisted; It is the vertical load in Z direction of the jumper string of lines (ground wire, DC wire, AC wire) when hoisted; is the installation dynamic coefficient, which is taken as 1.1; is the lifting coefficient, take 2.0; It is the additional load for hoisting, and the value is taken according to the specification;

[0214] All loads on the unlifted parts are 0.

[0215] The fifth embodiment of the present invention proposes a load combination design method for AC / DC hybrid tension transmission towers in light ice areas, and based on any of the above embodiments, as Figures 1 to 3 As shown in the figure, after the hoisting is completed, the anchoring is carried out. The lines on the tension tower are directly hung on the crossarm, so the anchoring can be carried out directly through the hanging point; in the anchoring process, the left and right ground wires are anchored first, and then the DC conductor or AC conductor is anchored in the order from right to left and from top to bottom. When the anchoring is carried out on the front side of the tension transmission tower, the load on the rear side is 0, and the design is carried out according to the longitudinal bending and transverse bending. The node loads of the lines on the tower in various directions at different anchoring progress during the anchoring process are calculated with the maximum rotation angle or the minimum rotation angle, including the following 14 calculation conditions:

[0216] Minimum turning angle, wind direction angle is 90 degrees, DL is on the anchor line, and the rest are not anchored;

[0217] Minimum turning angle, wind direction angle is 90 degrees, DL is anchored, DR is on the anchor line, and the rest are not anchored;

[0218] Minimum turning angle, wind direction angle is 90 degrees, ground line is anchored, Z-JL is on the anchor line, and the rest are not anchored;

[0219] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL are anchored, J-JU is on the anchor line, and the rest are not anchored;

[0220] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU are anchored, J-JL is on the anchor line, and the rest are not anchored;

[0221] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU, J-JL are anchored, Z-ZR is on the anchor line, and the rest are not anchored;

[0222] Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU, J-JL, Z-ZR are anchored, J-JR is anchoring;

[0223] At the maximum turning angle, the wind direction angle is 90 degrees, DL is on the anchor line, and the rest are not anchored;

[0224] At the maximum turning angle, the wind direction angle is 90 degrees, DL is anchored, DR is on the anchor line, and the rest are not anchored;

[0225] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line is anchored, Z-JL is on the anchor line, and the rest are not anchored;

[0226] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line and Z-JL are anchored, J-JU is on the anchor line, and the rest are not anchored;

[0227] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line, Z-JL, and J-JU are anchored, J-JL is on the anchor line, and the rest are not anchored;

[0228] At the maximum turning angle, the wind direction angle is 90 degrees, the ground line, Z-JL, J-JU, and J-JL are anchored, Z-ZR is on the anchor line, and the rest are not anchored;

[0229] At the maximum turning angle, the wind direction angle is 90 degrees. The ground line, Z-JL, J-JU, J-JL, and Z-ZR are anchored, and J-JR is anchoring.

[0230] Under 14 calculation conditions, the node loads of the anchor line on the front and rear sides of the tower are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0231]

[0232] Anchor line section:

[0233]

[0234]

[0235] Anchored part:

[0236]

[0237]

[0238] in, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) under the anchor line condition; It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when it is hoisted; It is the tension of temporary wires on one side (ground wire, DC conductor, AC conductor) when the wire is anchored, and the value is determined by referring to the tower load specification; To calculate the traction coefficient according to the line, take the interval of 1.05~1.15; The angle between the temporary cable and the ground is 45°;

[0239] All loads on the unanchored parts are 0.

[0240] The sixth embodiment of the present invention proposes a load combination design method for AC / DC mixed voltage tension transmission tower in light ice area, and based on any of the above embodiments, as Figures 1 to 3 As shown in the figure, for AC and DC mixed voltage, the arrangement is not completely symmetrical, and the maximum bending moment and maximum torsion need to be considered. The line break is based on the tension on the front side of the tension transmission tower being greater than the standard value, the tension on the rear side being less than the standard value, and both the front and rear sides being downward pressure loads. The maximum or minimum rotation angle is used to calculate the node loads of the line on the tower in all directions when any two lines are broken in the absence of wind and a fault occurs, including the following 18 calculation conditions:

[0241] Maximum turning angle / minimum turning angle, cut off at DL and Z-JL;

[0242] Maximum turning angle / minimum turning angle, breaking DL and J-JL;

[0243] Maximum turning angle / minimum turning angle, cut off at DR and Z-JR;

[0244] Maximum turning angle / minimum turning angle, cut off at DR and J-JR;

[0245] Maximum turning angle / minimum turning angle, cut off at J-JL and J-JR;

[0246] Maximum turning angle / minimum turning angle, cut at Z-JL and J-JL;

[0247] Maximum turning angle / minimum turning angle, breaking at Z-JR and J-JR;

[0248] Maximum turning angle / minimum turning angle, break at Z-JR and J-ZU;

[0249] Maximum turning angle / minimum turning angle, break at J-ZU and J-JR.

[0250] Under 18 calculation conditions, the node loads of the wire on the front and rear sides of the tower when the wire breaks and causes a fault are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0251]

[0252]

[0253]

[0254] in, It is the Y-direction tension of one side of the wire (ground wire, DC wire, AC wire) when the wire is broken; It is the Z-direction vertical load of the line (ground wire, DC wire, AC wire) when it is broken.

[0255] The seventh embodiment of the present invention proposes a load combination design method for AC / DC mixed voltage tension transmission tower in light ice area, and based on any of the above embodiments, as Figures 1 to 3 As shown, since it is in a light ice area, its uneven ice coverage only considers the maximum bending moment situation, so the uneven ice needs to consider two wind direction angles: 90° and 0°. The vertical load properties include downward pressure vertical load and upward pull vertical load. In this manual, the parts that do not require the vertical load properties of the front and rear sides of the tension transmission tower are all defaulted to downward pressure vertical loads; at the same time, considering the simultaneous operation of AC and DC lines and the single-circuit operation of DC lines, the vertical load is considered according to the maximum vertical load. The node loads of the lines on the towers in all directions at different wind direction angles under uneven icing are calculated with the maximum rotation angle or the minimum rotation angle, including the following 6 calculation conditions:

[0256] Maximum turning angle, wind direction angle is 90 degrees, maximum bending moment, AC and DC lines are running simultaneously;

[0257] Maximum turning angle, wind direction angle is 90 degrees, maximum bending moment, single-circuit operation of DC line;

[0258] Maximum rotation angle, wind direction angle is 90 degrees, maximum bending moment, one side of the front and rear side vertical loads of the tension transmission tower is downward pressure vertical load, the other side is upward pull vertical load, AC and DC lines are running at the same time;

[0259] Minimum turning angle, wind direction angle is 0 degrees, maximum bending moment, AC and DC lines are running simultaneously;

[0260] Minimum turning angle, wind direction angle is 0 degrees, maximum bending moment, single-circuit operation of DC line;

[0261] Minimum turning angle, wind direction angle of 0 degrees, maximum bending moment, one side of the front and rear side vertical loads of the tension transmission tower is a downward pressure vertical load, and the other side is an upward pull vertical load, and the AC and DC lines are running simultaneously.

[0262] Under 6 calculation conditions, the node loads of the lines on the front and rear sides of the tower under uneven ice coverage are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows:

[0263]

[0264]

[0265] When the load is downward:

[0266]

[0267] When pulling up the load:

[0268]

[0269] in, It is the X-direction wind load of one side of the wire (ground wire, DC wire, AC wire) under the condition of uneven ice; It is the Y-direction tension of the lines (ground wire, DC wire, AC wire) on one side under uneven ice conditions; It is the downward pressure load on the lines (ground wire, DC wire, AC wire) under uneven ice conditions.

[0270] In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0271] Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area, wherein the tension transmission tower comprises an iron tower and a wire, wherein the wire comprises a ground wire part, a DC conductor part, and an AC conductor part arranged on the iron tower, and the wire is arranged at a certain angle to the advancing direction of the tension transmission tower, characterized in that: The following steps are involved: S1. The front and rear vertical loads of the designed tension transmission tower are different combinations of downward pressure vertical loads or upward pull vertical loads. Considering the tension at the front and rear of the transmission tower, calculate the node loads of the line on the tower in all directions under different wind direction angles and at the maximum or minimum rotation angle under normal operation; S2. Design the vertical loads on the front and rear sides of the tension transmission tower as different combinations of downward pressure vertical loads or upward pull vertical loads, taking into account the tension on the front and rear sides of the transmission tower, and calculate the node loads on the tower in all directions under different wind direction angles and after taking the maximum or minimum rotation angle when operating under icing conditions; S3. Under the conditions that the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, and the rear tension is less than the standard value, calculate the node loads of the line on the tower in all directions when the maximum or minimum rotation angle is taken under the installation condition; the installation condition includes the hoisting process and the anchor line process; S4. Consider the maximum bending moment and maximum torsion, and calculate the node loads of the lines on the tower in all directions when any two lines are broken and a fault occurs in the absence of wind, using the maximum rotation angle or the minimum rotation angle; S5. Under the conditions of maximum bending moment and maximum vertical load, the vertical load properties of the front and rear vertical loads of the tension transmission tower are considered, and the node loads of the lines on the tower in all directions at different wind angles under uneven icing are calculated using the maximum rotation angle or the minimum rotation angle.

2. The load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 1 is characterized in that: A calculation coordinate system is specified, where the X-axis direction is the horizontal crossarm direction, the Y-axis direction is perpendicular to the horizontal crossarm direction, and the Z-axis direction is the vertical direction perpendicular to the XY plane.

3. The load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 2 is characterized in that: S1 includes the single-circuit operation of DC lines and the simultaneous operation of AC and DC lines. The calculation is performed at wind direction angles of 90 degrees and 0 degrees. Under normal operation, the calculation conditions include the following: At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time; At the maximum turning angle, the wind direction angle is 90 degrees. The front and rear vertical loads of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The AC and DC lines are running at the same time. Maximum rotation angle, wind direction angle is 90 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time; At the maximum turning angle, the wind direction angle is 90 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower is less than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the vertical load on the front side of the tension transmission tower is 0, the vertical load on the rear side is the upward vertical load, the tension on the front and rear sides of the tension transmission tower are both less than the standard value, and the AC and DC lines are running at the same time; At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the DC line is in single-circuit operation; Maximum turning angle, wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the DC line is in single-circuit operation; Minimum turning angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the DC line is in single-circuit operation; At the minimum turning angle, the wind direction angle is 0 degrees. The vertical load on the front and rear sides of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The DC line operates in a single loop.

4. The load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 3 is characterized in that: The node loads of the lines on the front and rear sides of the tower under normal operation are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows: When the load is downward: When pulling up the load: in, is the structural importance coefficient; is the permanent load partial factor; is the variable load combination factor; is the variable load combination factor of the operating condition; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; The angle between the line on the front or rear side of the tension transmission tower and the forward direction of the tension transmission tower; is the X-direction wind load on one side line; It is the Y-direction tension of the line on one side; The line Z on one side presses down the vertical load. The Z side line is an upward vertical load and is considered as a live load.

5. The load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 2 is characterized in that: When calculating the icing operation, the node loads of the lines on the tower in all directions include the following calculation conditions: At the maximum turning angle, the wind direction angle is 90 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time; At the maximum turning angle, the wind direction angle is 90 degrees. The front and rear vertical loads of the tension transmission tower are both downward vertical loads. The tension on the front side of the tension transmission tower is greater than the standard value, and the tension on the rear side is less than the standard value. The AC and DC lines are running at the same time. Maximum rotation angle, wind direction angle is 90 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time; At the maximum turning angle, the wind direction angle is 90 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower is less than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the tensions on the front and rear sides of the tension transmission tower are greater than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the front and rear vertical loads of the tension transmission tower are both downward vertical loads, the front tension of the tension transmission tower is greater than the standard value, the rear tension is less than the standard value, and the AC and DC lines are running at the same time; Minimum rotation angle, wind direction angle is 0 degrees, the front side vertical load of the tension transmission tower is downward vertical load, the rear side vertical load is upward vertical load, the front side tension of the tension transmission tower is greater than the standard value, the rear side tension is less than the standard value, and the AC and DC lines are running at the same time; At the minimum turning angle, the wind direction angle is 0 degrees, the vertical load on the front side of the tension transmission tower is 0, and the vertical load on the rear side is the upward vertical load. The tension on the front and rear sides of the tension transmission tower are both less than the standard value, and the AC and DC lines operate simultaneously.

6. The method for designing load combinations of AC / DC mixed-voltage tension transmission towers in light ice areas according to claim 5 is characterized in that: The node loads of the lines on the front and rear sides of the tower under ice-covered operation are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows: When the load is downward: When pulling up the load: in, is the structural importance coefficient; is the permanent load partial factor; is the variable load combination factor; is the variable load combination factor of the operating condition; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; The angle between the line on the front or rear side of the tension transmission tower and the forward direction of the tension transmission tower; The line Z on one side presses down the vertical load. The upward vertical load of line Z on one side is considered as live load; is the X-direction wind load on one side of the line under ice cover; It is the Y-direction tension when one side of the line is covered with ice; It is the downward pressure load of the line when it is covered with ice.

7. The load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 2 is characterized in that: The hoisting process needs to verify the stress of the local components of the tower. The DC conductor V string is hoisted through the hanging point of the DC cross arm, and then the three-phase AC conductor I string is hoisted step by step from left to right and from top to bottom. The hoisting process includes the following calculation conditions: At the maximum turning angle, the wind direction angle is 90 degrees, the Z-JL jumper string is hoisted, and the other conductors are not hoisted; At the maximum turning angle, the wind direction angle is 90 degrees, the Z-JR jumper string is hoisted, and the other conductors are not hoisted; At the maximum turning angle, the wind direction angle is 90 degrees, the J-JU jumper string is hoisted, and the other conductors are not hoisted; At the maximum turning angle, the wind direction angle is 90 degrees, the J-JL jumper string is hoisted, and the other conductors are not hoisted; At the maximum turning angle, the wind direction angle is 90 degrees, the J-JR jumper string is hoisted, and the other conductors are not hoisted; Minimum turning angle, wind direction angle is 90 degrees, Z-JL jumper string is hoisted, and other conductors are not hoisted; Minimum turning angle, wind direction angle is 90 degrees, Z-JR jumper string is hoisted, and other conductors are not hoisted; Minimum turning angle, wind direction angle is 90 degrees, J-JU jumper string is hoisted, and other conductors are not hoisted; Minimum turning angle, wind direction angle is 90 degrees, J-JL jumper string is hoisted, and other conductors are not hoisted; Minimum turning angle, wind direction angle is 90 degrees, J-JR jumper string is hoisted, and other conductors are not hoisted.

8. The method for designing load combinations of AC / DC mixed-voltage tension transmission towers in light ice areas according to claim 7 is characterized in that: The node loads of the lines on the front and rear sides of the tower during the hoisting process are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows: Load of hoisting jumper string: In the formula, is the structural importance coefficient; is the variable load combination factor; is the variable load combination factor of the operating condition; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; The angle between the line on the front or rear side of the tension transmission tower and the forward direction of the tension transmission tower; It is the X-direction wind load of one side line when hoisted; It is the Y-direction tension when one side of the line is hoisted; It is the vertical load in Z direction when the line jumper string is hoisted; is the installation dynamic coefficient; is the lifting coefficient; Additional load for hoisting; All loads on the unmounted parts are 0.

9. The method for designing load combinations of AC / DC mixed-voltage tension transmission towers in light ice areas according to claim 2 is characterized in that: In the anchoring process, first anchor the left and right ground wires, and then anchor the DC conductor or AC conductor in the order from right to left and from top to bottom. When the front side of the tension transmission tower is anchored, the load on the rear side is 0, and the design is carried out according to the longitudinal bending and transverse bending. The node loads of the line on the tower in various directions at different anchoring progress during the anchoring process are calculated with the maximum rotation angle or the minimum rotation angle, including the following calculation conditions: Minimum turning angle, wind direction angle is 90 degrees, DL is on the anchor line, and the rest are not anchored; Minimum turning angle, wind direction angle is 90 degrees, DL is anchored, DR is on the anchor line, and the rest are not anchored; Minimum turning angle, wind direction angle is 90 degrees, ground line is anchored, Z-JL is on the anchor line, and the rest are not anchored; Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL are anchored, J-JU is on the anchor line, and the rest are not anchored; Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU are anchored, J-JL is on the anchor line, and the rest are not anchored; Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU, J-JL are anchored, Z-ZR is on the anchor line, and the rest are not anchored; Minimum turning angle, wind direction angle is 90 degrees, ground line, Z-JL, J-JU, J-JL, Z-ZR are anchored, J-JR is anchoring; At the maximum turning angle, the wind direction angle is 90 degrees, DL is on the anchor line, and the rest are not anchored; At the maximum turning angle, the wind direction angle is 90 degrees, DL is anchored, DR is on the anchor line, and the rest are not anchored; At the maximum turning angle, the wind direction angle is 90 degrees, the ground line is anchored, Z-JL is on the anchor line, and the rest are not anchored; At the maximum turning angle, the wind direction angle is 90 degrees, the ground line and Z-JL are anchored, J-JU is on the anchor line, and the rest are not anchored; At the maximum turning angle, the wind direction angle is 90 degrees, the ground line, Z-JL, and J-JU are anchored, J-JL is on the anchor line, and the rest are not anchored; At the maximum turning angle, the wind direction angle is 90 degrees, the ground line, Z-JL, J-JU, and J-JL are anchored, Z-ZR is on the anchor line, and the rest are not anchored; At the maximum turning angle, the wind direction angle is 90 degrees. The ground line, Z-JL, J-JU, J-JL, and Z-ZR are anchored, and J-JR is anchoring.

10. A load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 9, characterized in that: The node loads of the anchor line on the front and rear sides of the tower are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows: Anchor line section: Anchored part: in, is the structural importance coefficient; is the permanent load partial factor; is the variable load combination factor; is the variable load combination factor of the operating condition; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; The angle between the line on the front or rear side of the tension transmission tower and the forward direction of the tension transmission tower; is the installation dynamic coefficient; The line Z on one side presses downwards; is the X-direction wind load on one side of the line under the anchor line condition; It is the Y-direction tension when one side of the line is hoisted; It is the tension of temporary wire on one side of the line when it is anchored, and the value is determined by referring to the tower load specification; is the traction coefficient according to the line; It is the angle between the temporary guy wire and the ground; Additional load for hoisting; All loads on the unanchored parts are 0.

11. The method for designing load combinations of AC / DC mixed-voltage tension transmission towers in light ice areas according to claim 2 is characterized in that: The line break is based on the tension of the front side of the tension transmission tower being greater than the standard value, the tension of the rear side being less than the standard value, and both the front and rear sides being downward pressure loads. The maximum or minimum rotation angle is used to calculate the node loads of the line on the tower in all directions when any two lines are broken in the windless condition, including the following calculation conditions: Maximum turning angle / minimum turning angle, cut off at DL and Z-JL; Maximum turning angle / minimum turning angle, breaking DL and J-JL; Maximum turning angle / minimum turning angle, cut off at DR and Z-JR; Maximum turning angle / minimum turning angle, cut off at DR and J-JR; Maximum turning angle / minimum turning angle, cut off at J-JL and J-JR; Maximum turning angle / minimum turning angle, cut at Z-JL and J-JL; Maximum turning angle / minimum turning angle, breaking at Z-JR and J-JR; Maximum turning angle / minimum turning angle, break at Z-JR and J-ZU; Maximum turning angle / minimum turning angle, break at J-ZU and J-JR.

12. A load combination design method for AC / DC mixed voltage tension transmission tower in light ice area according to claim 11, characterized in that: The node loads of the wire on the front and rear sides of the tower are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively when the wire breaks and causes a fault. The calculation method is as follows: in, is the structural importance coefficient; is the permanent load partial factor; is the variable load combination factor; is the variable load combination factor of the operating condition; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; The angle between the line on the front or rear side of the tension transmission tower and the forward direction of the tension transmission tower; The line Z on one side presses downwards; It is the Y-direction tension of one side of the line when it is broken; It is the vertical load in Z direction when the line is broken.

13. The method for designing load combinations of AC / DC mixed-voltage tension transmission towers in light ice areas according to claim 2, characterized in that: The vertical load properties include downward pressure vertical load and upward pull vertical load. The wind direction angles of 90 degrees and 0 degrees are selected. At the same time, the simultaneous operation of AC and DC lines and the single-circuit operation of DC lines are considered. The node loads of the lines on the towers in various directions at different wind direction angles under uneven icing are calculated at the maximum rotation angle or the minimum rotation angle, including the following calculation conditions: Maximum turning angle, wind direction angle is 90 degrees, maximum bending moment, AC and DC lines are running simultaneously; Maximum turning angle, wind direction angle is 90 degrees, maximum bending moment, single-circuit operation of DC line; Maximum rotation angle, wind direction angle is 90 degrees, maximum bending moment, one side of the front and rear side vertical loads of the tension transmission tower is downward pressure vertical load, the other side is upward pull vertical load, AC and DC lines are running at the same time; Minimum turning angle, wind direction angle is 0 degrees, maximum bending moment, AC and DC lines are running simultaneously; Minimum turning angle, wind direction angle is 0 degrees, maximum bending moment, single-circuit operation of DC line; Minimum turning angle, wind direction angle of 0 degrees, maximum bending moment, one side of the front and rear side vertical loads of the tension transmission tower is a downward pressure vertical load, and the other side is an upward pull vertical load, and the AC and DC lines are running simultaneously.

14. A load combination design method for AC / DC mixed-voltage tension transmission tower in light ice area according to claim 13, characterized in that: The node loads of the lines on the front and rear sides of the tower under uneven ice coverage are calculated in the X-axis direction, Y-axis direction and Z-axis direction respectively. The calculation method is as follows: When the load is downward: When pulling up the load: In the formula, is the structural importance coefficient; is the permanent load partial factor; is the variable load combination factor; is the variable load combination factor of the operating condition; is the distribution coefficient along the X direction at different angles of line wind load, is the distribution coefficient along the Y direction at different angles of the line load; The angle between the line on the front or rear side of the tension transmission tower and the forward direction of the tension transmission tower; The line Z on one side presses down the vertical load. The upward vertical load of line Z on one side is considered as live load; is the X-direction wind load on one side of the line under uneven ice conditions; It is the Y-direction tension when the lines on one side are unevenly iced; It is the downward pressure load of the line under uneven ice conditions.

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