Use method of power transmission line phase-to-ground spacer coping with sag change

Abstract

The invention discloses a use method of a power transmission line phase-to-ground spacer for coping with sag change, and the method comprises the following steps: determining the hanging point position of the phase-to-ground spacer on a wire according to the span of a power transmission line; according to the annual maximum temperature difference of the region where the power transmission line is located, calculating the maximum variation of the conductor sag at the hanging point position; determining an installation angle between the phase-to-ground spacer and the ground according to the prevailing wind direction of the region where the power transmission line is located; calculating the position and height of a fixed ground anchor at the ground end according to the height to the ground of the hanging point position, the maximum variation of the wire sag at the hanging point position and the mounting angle between the phase-ground spacer and the ground; calculating the initial installation pre-tightening force of the phase-to-ground spacer; and the phase-to-ground spacer is installed between the hanging point position and the fixed ground anchor, the length of a stay wire of the phase-to-ground spacer is adjusted, and initial installation pre-tightening force is applied. According to the invention, the problem that the long-term application of the phase-to-ground spacer is limited by the sag change of the lead is solved, and the installation of the phase-to-ground spacer can always achieve a good anti-galloping effect throughout the year.

Description

Technical Field

[0001] The invention belongs to the field of operation and maintenance of power system transmission lines, and in particular relates to a method for using a phase-to-ground spacer rod of a transmission line for coping with sag changes. Background Art

[0002] The dancing of transmission line conductors can cause accidents such as pole and tower collapse, line breakage, string drop, short circuit, tripping and large-scale power outages, which will cause significant losses to the power system and threaten the safe and stable operation of the power grid and the reliability of the power supply system. Phase-to-ground spacers are a relatively new type of anti-dancing device. Its working principle is to connect a certain position on the conductor to the ground through a phase-to-ground spacer, which is equivalent to adding an additional fixed constraint point within the line span, thereby achieving the effect of limiting the dancing amplitude of the conductor. However, the problem with phase-to-ground spacers is that they cannot be put into use for a long time. This is because there is a certain temperature difference in environmental changes within a year. Due to the thermal expansion and contraction effect, the sag of the conductor will change, and the length of the phase-to-ground spacer cannot be adjusted automatically. When the sag is too large in summer, the phase-to-ground spacer may lose its tension on the conductor, or the sag contraction in winter may aggravate the wear and fatigue of the conductor. The existing countermeasures are to use phase-to-ground spacers only in seasons prone to dancing, and dismantle them immediately after the anti-dancing is completed, or the staff manually adjusts the length of the phase-to-ground spacer wire according to the sag changes on site in different seasons. However, both methods will greatly increase the workload of line operation and maintenance personnel and increase operation and maintenance costs. Summary of the invention

[0003] In view of the shortcomings of the existing methods, the present invention provides a method for using a phase-to-ground spacer for a power transmission line that can cope with sag changes.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A method for using a phase-to-ground spacer for a power transmission line to cope with sag changes comprises the following steps:

[0006] S1. Determine the hanging point position of the phase-to-ground spacer on the conductor according to the span of the transmission line;

[0007] S2. Calculate the maximum change in the conductor sag at the hanging point according to the maximum temperature difference throughout the year in the area where the transmission line is located;

[0008] S3. Determine the installation angle between the phase-to-ground spacer and the ground according to the dominant wind direction in the area where the transmission line is located;

[0009] S4, calculating the fixed anchor position and height of the ground end according to the height of the hanging point position to the ground, the maximum change of the conductor sag at the hanging point position described in step S2, and the installation angle between the phase-to-ground spacer and the ground described in step S3;

[0010] S5. Calculate the initial preload force of the phase-to-ground spacer during installation;

[0011] S6. Install a phase-to-ground spacer between the hanging point position described in step S1 and the fixed ground anchor described in step S4, adjust the length of the phase-to-ground spacer wire, and apply the initial installation preload calculated in step S5.

[0012] Preferably, the step S1 of determining the hanging point position of the phase-to-ground spacer on the conductor according to the span of the transmission line includes:

[0013] When the span of the transmission line is ≤400 meters, one phase-to-ground spacer is installed for each phase conductor, and the hanging point of the phase-to-ground spacer is set at 1 / 2 of the span of the transmission line;

[0014] When the span of the transmission line is 400m<600m, two phase-to-ground spacers are installed for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 3 and 2 / 3 of the span of the transmission line;

[0015] When the span of the transmission line is 600m<900m, three phase-to-ground spacers are installed for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 5, 1 / 2 and 4 / 5 of the span of the transmission line;

[0016] When the span of the transmission line is greater than 900 meters, four phase-to-ground spacers are set for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 10, 2 / 5, 3 / 5 and 9 / 10 of the transmission line span.

[0017] Preferably, the calculation formula for the maximum change in the conductor sag at the hanging point position described in step S2 is:

[0018]

[0019] Where, t1 and t2 are the highest and lowest temperatures in the area where the transmission line is located in a year, respectively, ℃; t0 is the manufacturing temperature of the conductor, ℃; L1 and L2 are the corresponding conductor lengths at t1 and t2, respectively, m; σ cp1 , σ cp2 are the average stress of the conductor in the span at temperatures t1 and t2, MPa; σ 01 , σ 02 are the stress at the lowest point of the conductor sag at temperatures t1 and t2, MPa; E is the comprehensive elastic coefficient of the conductor, MPa; α is the temperature linear expansion coefficient of the conductor, 1 / ℃; γ is the conductor load, MPa / m; l is the line span, m; h is the height difference between the two towers, m; Δf x It is the maximum change of conductor sag at the hanging point throughout the year, m.

[0020] Preferably, the step S3 of determining the installation angle between the phase-to-ground spacer and the ground according to the dominant wind direction in the area where the power transmission line is located includes:

[0021] The climbing direction of the phase-to-ground spacer is installed in the opposite direction to the prevailing wind direction in the area where the transmission line is located, with a deviation angle of 0° to 15°, and the installation angle between the phase-to-ground spacer and the ground is 60° to 75°.

[0022] Preferably, the step S4 of calculating the fixed ground anchor position and height of the ground end according to the height of the hanging point position to the ground, the maximum change in the sag of the conductor at the hanging point position in step S2, and the installation angle between the phase-to-ground spacer and the ground in step S3 includes:

[0023] The fixed anchor position of the ground end is determined by the installation angle between the phase-to-ground spacer and the ground;

[0024] When the height of the hanging point to the ground is ≤30 meters and the maximum change of the conductor sag is less than 5 meters, the fixed anchor height is 2 to 3 meters;

[0025] When the height of the hanging point from the ground is 30 meters < ≤ 60 meters and the maximum change of the conductor sag is < 8 meters, the fixed anchor height is 3 to 5 meters;

[0026] When the height of the hanging point to the ground is 60 meters < ≤ 100 meters and the maximum change of the conductor sag is < 10 meters, the fixed anchor height is 5 to 8 meters;

[0027] When the height of the hanging point above the ground is greater than 100 meters and the maximum change in conductor sag is ≥10 meters, the fixed anchor height is 8 to 12 meters.

[0028] Preferably, the height of the hanging point position above the ground in step S4 is a height measured with the horizontal plane of the ground below the corresponding wire hanging point as a reference benchmark.

[0029] Preferably, the calculation of the initial installation preload of the phase-to-ground spacer described in step S5 includes: when the conductor sag changes with temperature in different seasons, the phase-to-ground spacer always exerts tension on the conductor, and the tension range does not exceed the specified value that causes fatigue of the phase-to-ground spacer wire.

[0030] Preferably, the step S6 of installing a phase-to-ground spacer between the hanging point position of the step S1 and the fixed ground anchor of the step S4, adjusting the length of the phase-to-ground spacer wire, and applying the initial installation preload calculated in the step S5 includes:

[0031] The upper end of the phase-to-ground spacer is fixed on the conductor, the lower end of the phase-to-ground spacer is connected to the pull wire, and the other end of the pull wire is tied and bolted to the fixed anchor;

[0032] The initial installation preload is adjusted by adjusting the binding length of the tension wire on the fixed ground anchor, and the magnitude of the initial installation preload is measured by a tension meter.

[0033] Preferably, a wire clamping groove is provided on the top of the fixed ground anchor, a pull wire is clamped in the wire clamping groove, and a plurality of anti-escape buckles are evenly provided on the edge of the wire clamping groove, and the anti-escape buckles are used to fix the pull wire in the wire clamping groove.

[0034] Preferably, when the maximum change in conductor sag is greater than 20 meters, a circle of wire-holding grooves is respectively provided at a position half the height of the fixed anchor and at the top of the fixed anchor.

[0035] The positive beneficial effects of the present invention are:

[0036] 1. The present invention solves the problem that the long-term application of phase-to-ground spacers is limited by the sag change of conductors, ensures that the installation of phase-to-ground spacers can always play a good anti-dancing effect throughout the year, and greatly saves the labor cost caused by seasonal installation and disassembly of phase-to-ground spacers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the installation position and installation angle of the phase-to-ground spacer of the present invention.

[0038] Figure 2 This is a top view of the pull wire of the present invention being fixed on a fixed ground anchor.

[0039] Figure 3 It is a schematic diagram of a two-section fixed ground anchor of the present invention.

[0040] In the figure, 1-pole tower, 2-conductor, 3-phase-to-ground spacer, 4-guy wire, 5-fixed ground anchor, 6-anti-slip buckle, 7-cable clamping groove. DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with some specific embodiments.

[0042] A method for using a phase-to-ground spacer for a power transmission line to cope with sag changes comprises the following steps:

[0043] S1. Determine the hanging point position of the phase-to-ground spacer on the conductor according to the span of the transmission line;

[0044] S2. Calculate the maximum change in the conductor sag at the hanging point according to the maximum temperature difference throughout the year in the area where the transmission line is located;

[0045] S3. Determine the installation angle between the phase-to-ground spacer and the ground according to the dominant wind direction in the area where the transmission line is located;

[0046] S4, calculating the fixed anchor position and height of the ground end according to the height of the hanging point position to the ground, the maximum change of the conductor sag at the hanging point position described in step S2, and the installation angle between the phase-to-ground spacer and the ground described in step S3;

[0047] S5. Calculate the initial preload force of the phase-to-ground spacer during installation;

[0048] S6. Install a phase-to-ground spacer between the hanging point position described in step S1 and the fixed ground anchor described in step S4, adjust the length of the phase-to-ground spacer wire, and apply the initial installation preload calculated in step S5.

[0049] Furthermore, the step S1 of determining the hanging point position of the phase-to-ground spacer on the conductor according to the span of the transmission line includes:

[0050] When the span of the transmission line is ≤400 meters, one phase-to-ground spacer is installed for each phase conductor, and the hanging point of the phase-to-ground spacer is set at 1 / 2 of the span of the transmission line;

[0051] When the span of the transmission line is 400m<600m, two phase-to-ground spacers are installed for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 3 and 2 / 3 of the span of the transmission line;

[0052] When the span of the transmission line is 600m<900m, three phase-to-ground spacers are installed for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 5, 1 / 2 and 4 / 5 of the span of the transmission line;

[0053] When the span of the transmission line is greater than 900 meters, four phase-to-ground spacers are set for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 10, 2 / 5, 3 / 5 and 9 / 10 of the transmission line span.

[0054] Furthermore, the calculation formula for the maximum change in the conductor sag at the hanging point position described in step S2 is:

[0055]

[0056]

[0057] Where, t1 and t2 are the highest and lowest temperatures in the area where the transmission line is located in a year, respectively, ℃; t0 is the manufacturing temperature of the conductor, ℃; L1 and L2 are the corresponding conductor lengths at t1 and t2, respectively, m; σ cp1 , σ cp2 are the average stress of the conductor in the span at temperatures t1 and t2, MPa; σ 01 , σ 02are the stress at the lowest point of the conductor sag at temperatures t1 and t2, MPa; E is the comprehensive elastic coefficient of the conductor, MPa; α is the temperature linear expansion coefficient of the conductor, 1 / ℃; γ is the conductor load, MPa / m; l is the line span, m; h is the height difference between the two towers, m; Δf x It is the maximum change of conductor sag at the hanging point throughout the year, m.

[0058] If the transmission line is located in a strong wind and ice-covered area, the ice weight load, ice-free wind pressure load and ice-covered wind pressure load need to be calculated when calculating the conductor load.

[0059] Furthermore, the step S3 of determining the installation angle between the phase-to-ground spacer and the ground according to the dominant wind direction in the area where the power transmission line is located includes:

[0060] The climbing direction of the phase-to-ground spacer is installed in the opposite direction to the prevailing wind direction in the area where the transmission line is located, with a deviation angle of 0° to 15°, and the installation angle between the phase-to-ground spacer and the ground is 60° to 75°.

[0061] Further, the step S4 calculates the fixed ground anchor position and height of the ground end according to the height of the hanging point position to the ground, the maximum change of the conductor sag at the hanging point position in step S2, and the installation angle between the phase-to-ground spacer and the ground in step S3, including:

[0062] The fixed anchor position of the ground end is determined by the installation angle between the phase-to-ground spacer and the ground;

[0063] When the height of the hanging point to the ground is ≤30 meters and the maximum change of the conductor sag is less than 5 meters, the fixed anchor height is 2 to 3 meters;

[0064] When the height of the hanging point from the ground is 30 meters < ≤ 60 meters and the maximum change of the conductor sag is < 8 meters, the fixed anchor height is 3 to 5 meters;

[0065] When the height of the hanging point to the ground is 60 meters < ≤ 100 meters and the maximum change of the conductor sag is < 10 meters, the fixed anchor height is 5 to 8 meters;

[0066] When the height of the hanging point above the ground is greater than 100 meters and the maximum change in conductor sag is ≥10 meters, the fixed anchor height is 8 to 12 meters.

[0067] Furthermore, the height of the hanging point position above the ground in step S4 is a height measured with the horizontal plane of the ground below the corresponding wire hanging point as a reference benchmark.

[0068] Furthermore, the calculation of the initial installation preload of the phase-to-ground spacer described in step S5 includes: when the conductor sag changes with temperature in different seasons, the phase-to-ground spacer always exerts tension on the conductor, and the tension range does not exceed the specified value that causes fatigue of the phase-to-ground spacer wire.

[0069] Further, in step S6, a phase-to-ground spacer is installed between the hanging point position in step S1 and the fixed ground anchor in step S4, the length of the phase-to-ground spacer wire is adjusted, and the initial installation preload calculated in step S5 is applied. Figure 1 and Figure 2 ,include:

[0070] The pole towers 1 are connected with conductors 2, the upper end of the phase-to-ground spacer 3 is fixed on the conductor 2, the lower end of the phase-to-ground spacer 3 is connected with a guy wire 4, and the other end of the guy wire 4 is tied and bolted to a fixed ground anchor 5;

[0071] The initial installation preload is adjusted by adjusting the binding length of the tension wire on the fixed ground anchor, and the magnitude of the initial installation preload is measured by a tension meter.

[0072] Further, see Figure 1 and Figure 2 A wire clamping groove 7 is arranged on the top of the fixed ground anchor 5, in which a pull wire 4 is clamped, and a plurality of anti-escape buckles 6 are evenly arranged on the edge of the wire clamping groove 7, and the anti-escape buckles 6 are used to fix the pull wire 4 in the wire clamping groove 7.

[0073] Further, see Figure 3 When the maximum change of the conductor sag is greater than 20 meters, a circle of wire-holding grooves is respectively set at half the height of the fixed anchor and at the top of the fixed anchor.

[0074] Example 1

[0075] The present invention is described below with reference to a specific transmission line. The line span is 574 meters, the dominant wind direction in the area where the line is located is northerly, and the wind attack angle is 90°. According to the method for using the phase-to-ground spacer described in the present invention, two phase-to-ground spacers are required for each phase conductor, and the hanging points are located at 1 / 3 and 2 / 3 of the line span respectively; the maximum change in conductor sag is 3 meters, the phase-to-ground spacer is installed in the direction against the wind, the deviation angle is 0°, and the installation angle with the ground is 68°, such as Figure 1 and 2 As shown in the figure, α is the installation angle between the phase-to-ground spacer and the ground, α=68°, the hanging point is 45 meters above the ground, the fixed anchor position is 14 meters offset from the line directly below, the height is 4 meters, and the initial installation preload force is 8kN. After the phase-to-ground spacer is installed according to the method shown in the figure, it can play an anti-dancing role throughout the year, and there is no need for personnel to perform periodic disassembly and erection work.

[0076] In some extreme areas, due to the large temperature difference within a year, the conductor sag changes greatly, so a two-stage fixed anchor design can be used, such as Figure 3As shown, the method of use is: the installation steps are still the same as those mentioned above, the pull wire of the phase-to-ground spacer is bundled and wrapped around the wire retaining groove on the top of the fixed anchor and tightened, the function of the anti-slip buckle is to prevent the pull wire from being pulled out of the fixed anchor, when the sag of the conductor changes and causes the pull wire to become a critical state that cannot bear tension, at this time, the pull wire on the anchor is dragged downward to move it to the wire retaining groove in the middle of the fixed anchor, which is equivalent to adjusting the bundling length of the pull wire, thereby realizing the adjustment of the tension.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for using a phase-to-ground spacer for a power transmission line to cope with sag changes, characterized in that: The steps include: S1. Determine the hanging point position of the phase-to-ground spacer on the conductor according to the span of the transmission line; S2. Calculate the maximum change in the conductor sag at the hanging point according to the maximum temperature difference throughout the year in the area where the transmission line is located; S3. Determine the installation angle between the phase-to-ground spacer and the ground according to the dominant wind direction in the area where the transmission line is located; S4, calculating the fixed anchor position and height of the ground end according to the height of the hanging point position to the ground, the maximum change of the conductor sag at the hanging point position described in step S2, and the installation angle between the phase-to-ground spacer and the ground described in step S3; S5. Calculate the initial preload force of the phase-to-ground spacer during installation; S6. Install the phase-to-ground spacer between the hanging point position described in step S1 and the fixed ground anchor described in step S4, adjust the length of the phase-to-ground spacer wire, and apply the initial installation preload calculated in step S5.

2. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 1, characterized in that: The step S1 of determining the hanging point position of the phase-to-ground spacer on the conductor according to the span of the transmission line includes: When the span of the transmission line is ≤400 meters, one phase-to-ground spacer is installed for each phase conductor, and the hanging point of the phase-to-ground spacer is set at 1 / 2 of the span of the transmission line; When the span of the transmission line is 400m<600m, two phase-to-ground spacers are installed for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 3 and 2 / 3 of the span of the transmission line; When the span of the transmission line is 600m<900m, three phase-to-ground spacers are installed for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 5, 1 / 2 and 4 / 5 of the span of the transmission line; When the span of the transmission line is greater than 900 meters, four phase-to-ground spacers are set for each phase conductor, and the hanging points of the phase-to-ground spacers are set at 1 / 10, 2 / 5, 3 / 5 and 9 / 10 of the transmission line span.

3. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 1, characterized in that: The calculation formula for the maximum change in the conductor sag at the hanging point position described in step S2 is: Where, t1 and t2 are the highest and lowest temperatures in the area where the transmission line is located in a year, ℃; t0 is the manufacturing temperature of the wire, °C; L1 and L2 are the corresponding wire lengths at t1 and t2 respectively, m; σ cp1 , σ cp2 are the average stress of the conductor in the span at temperatures t1 and t2, MPa; σ 01 , σ 02 are the stress at the lowest point of the conductor sag at temperatures t1 and t2, MPa; E is the comprehensive elastic coefficient of the conductor, MPa; α is the temperature linear expansion coefficient of the conductor, 1 / ℃; γ is the conductor load, MPa / m; l is the line span, m; h is the height difference between the two towers, m; Δf x It is the maximum change of conductor sag at the hanging point throughout the year, m.

4. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 1, characterized in that: The step S3 of determining the installation angle between the phase-to-ground spacer and the ground according to the dominant wind direction in the area where the power transmission line is located includes: The climbing direction of the phase-to-ground spacer is installed in the opposite direction to the prevailing wind direction in the area where the transmission line is located, with a deviation angle of 0° to 15°, and the installation angle between the phase-to-ground spacer and the ground is 60° to 75°.

5. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 1, characterized in that: The step S4 of calculating the fixed ground anchor position and height of the ground end according to the height of the hanging point position to the ground, the maximum change of the conductor sag at the hanging point position in step S2, and the installation angle between the phase-to-ground spacer and the ground in step S3 includes: The fixed anchor position of the ground end is determined by the installation angle between the phase-to-ground spacer and the ground; When the height of the hanging point to the ground is ≤30 meters and the maximum change of the conductor sag is less than 5 meters, the fixed anchor height is 2 to 3 meters; When the height of the hanging point from the ground is 30 meters < ≤ 60 meters and the maximum change of the conductor sag is < 8 meters, the fixed anchor height is 3 to 5 meters; When the height of the hanging point to the ground is 60 meters < ≤ 100 meters and the maximum change of the conductor sag is < 10 meters, the fixed anchor height is 5 to 8 meters; When the height of the hanging point above the ground is greater than 100 meters and the maximum change in conductor sag is ≥10 meters, the fixed anchor height is 8 to 12 meters.

6. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 5, characterized in that: The height of the hanging point position above the ground described in step S4 is a height measured with the horizontal plane of the ground below the corresponding wire hanging point as a reference benchmark.

7. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 1, characterized in that: The calculation of the initial installation preload of the phase-to-ground spacer described in step S5 includes: when the conductor sag changes with temperature in different seasons, the phase-to-ground spacer always exerts tension on the conductor, and the tension range does not exceed the specified value that causes fatigue of the phase-to-ground spacer wire.

8. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 1, characterized in that: The step S6 of installing the phase-to-ground spacer between the hanging point position of the step S1 and the fixed ground anchor of the step S4, adjusting the length of the phase-to-ground spacer wire, and applying the initial installation preload calculated in the step S5 includes: The upper end of the phase-to-ground spacer is fixed on the conductor, the lower end of the phase-to-ground spacer is connected to the pull wire, and the other end of the pull wire is tied and bolted to the fixed anchor; The initial installation preload is adjusted by adjusting the binding length of the tension wire on the fixed ground anchor, and the magnitude of the initial installation preload is measured by a tension meter.

9. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 8, characterized in that: A wire clamping groove is arranged on the top of the fixed ground anchor, a pull wire is clamped in the wire clamping groove, and a plurality of anti-escape buckles are evenly arranged on the edge of the wire clamping groove, and the anti-escape buckles are used to fix the pull wire in the wire clamping groove.

10. The method for using the phase-to-ground spacer for a power transmission line to cope with sag changes according to claim 9, characterized in that: When the maximum change in conductor sag is greater than 20 meters, a circle of wire-holding grooves is respectively provided at a position half the height of the fixed anchor and at the top of the fixed anchor.

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