Equivalent test device for eccentric icing of conductors

Abstract

The embodiment of the present application provides an equivalent test device for eccentric icing of conductors, comprising: a conductor segment, used to simulate a transmission conductor segment, the conductor segment being horizontally arranged on a rotating shaft support mechanism and being freely rotatable relative to its own axis; a thin wire, the upper end of which is fixed to a fixed point of the conductor segment after being wound along the outer circumference of the conductor segment for a preset length, a pendant being suspended from the lower end of the thin wire, and drooping from the outer edge of the conductor segment under the action of the pendant; the torque generated by the pendant on the conductor segment with the axis as the rotation axis is equivalent to the torque of eccentric icing dispersed on the transmission conductor segment. The equivalent test device for eccentric icing of conductors of the embodiment of the present application can be used to analyze the anti-dancing effect of split rotary spacers, and can also be used to test the resistance of rotating wire clamps to eccentric icing.

Description

Technical Field

[0001] The present application relates to the technical field of electric power transmission, and in particular to an equivalent test device for eccentric icing of conductors. Background Art

[0002] Overhead transmission lines (referred to as lines) are important equipment for transmitting electric energy. They are composed of towers, conductors and other components. The conductors of AC lines include three phases: A, B and C. Under certain icing and strong wind conditions, uneven ice can form on the conductors, changing the aerodynamic properties of the conductors and easily causing large vibrations of the conductors, which is figuratively called dancing. Dancing can reduce the distance between the conductors and cause discharge faults; it can also increase the tension of the conductors and cause the collapse of the towers. It is one of the main faults that threaten the safety of power transmission.

[0003] Each phase conductor of a lower voltage line is a single conductor; each phase conductor of a higher voltage line is generally composed of several sub-conductors that are spaced a certain distance apart and arranged in a certain shape, called split conductors. According to the number of sub-conductors, split conductors are divided into two-split, three-split, four-split, six-split and eight-split conductors. On the tower, the sub-conductors of the split conductor are supported and fixed by suspension clamps or tension clamps; between the towers, a spacer can be installed along the conductor at a certain distance (for example, 45m) to support and fix the sub-conductors of the split conductor.

[0004] Generally, split conductors are more prone to galloping than single conductors. This is caused by the difference in ice coverage between single conductors and split conductors. In winter, strong winds move horizontally along the ground, blowing water vapor in the air toward the conductors and condensing into ice on the windward side of the conductors. This uneven ice coverage is called eccentric ice coverage (e.g. Figure 1a to Figure 1c The eccentric ice coating 6 attached to the conductor 2 is shown.

[0005] For a single conductor, the torque will cause the conductor to rotate an angle in the direction of the torque, so that the windward side of the conductor changes - a part of the conductor surface that was originally within the windward surface range rotates out of the windward surface and no longer continues to be covered with ice; a part of the conductor surface that is not within the windward surface range rotates into the windward surface and begins to be covered with ice - the windward side of the conductor (i.e., the ice-covered area) gradually changes with the rotation of the conductor, and finally a circle of relatively uniform ice is formed on the conductor (for example Figure 2 As shown in the figure, the uniformly iced conductor is similar to the un-iced conductor and is not easy to form lift, so the single conductor is not easy to gallop.

[0006] However, for the split conductor, since the spacer rod fixes the sub-conductor, although there is a torque of eccentric icing, the sub-conductor does not rotate, so its windward surface (i.e., icing area) is fixed. As time goes by, the ice on the windward surface gradually increases and becomes thicker, that is, the uneven eccentric icing becomes more and more serious. Compared with the uniformly iced conductor, this severely eccentrically iced conductor is more likely to form lift, so the split conductor is prone to dancing.

[0007] According to the above analysis, the Asahi Electric Technology Research Center of Japan first developed a split rotary spacer for suppressing the dancing of conductor ice, and the China Electric Power Research Institute first developed and applied similar products in China (such as Figure 3 As shown in the figure), the State Grid Corporation of China has formulated the "Technical Specifications for Split Rotary Spacers" Q / GDW718-2012. Some clamps of split rotary spacers (such as Figure 3 The two wire clamps on the left side of the middle wire can be designed as rotating wire clamps, hoping that the wire it clamps will have a free rotation effect and uniform ice coating effect similar to that of a single wire, so that the split wire can also suppress dancing. Theoretically, among various anti-dancing products and measures, the negative effects of the split rotary spacer are the smallest. For example, the centralized anti-dancing device increases the stress concentration point on the wire, which can easily cause fatigue damage to the wire; the interphase spacer can generate tensile and extrusion forces of uncertain direction at its installation point, which can easily cause damage to the interphase spacer, hardware and wire; and the split rotary spacer only replaces the original conventional spacer and hardly changes the original stress on the wire.

[0008] At present, split rotary spacers have been widely used, but power grid units generally reflect that its anti-galloping effect is not obvious. One possible reason is that the rotating wire clamp still has a large resistance to the rotation of the conductor. The torque generated by eccentric ice less than a certain thickness and mass cannot rotate the conductor, but it can cause line galloping; another possible reason is that although the conductors between the towers use split rotary spacers, the conductors clamped therein can rotate freely, but the conductors clamped by the suspension wire clamps or tension wire clamps on the towers are completely fixed and cannot rotate, which affects the overall rotation effect, icing effect of the conductor and the anti-galloping effect of the split rotary spacer. Therefore, quantitative testing of the influence of split rotary spacers, suspension wire clamps and tension wire clamps on the rotation performance of the conductor under the action of eccentric icing is a necessary prerequisite for further analyzing and improving the anti-galloping performance of split rotary spacers. However, there is currently no physical simulation device that can be used for eccentric icing tests on conductors. Summary of the invention

[0009] The purpose of the embodiments of the present application is to provide an equivalent test device for eccentric icing of conductors, so as to be used for physical simulation research on the influence of eccentric icing of conductors on the galloping of transmission lines.

[0010] To achieve the above-mentioned purpose, the embodiment of the present application provides an equivalent test device for eccentric icing of a conductor, comprising:

[0011] A conductor segment, used to simulate a transmission conductor segment, wherein the conductor segment is horizontally arranged on the rotating shaft support mechanism and can rotate freely relative to its own axis;

[0012] A thin wire, the upper end of which is fixed to a fixed point on the wire segment after being wound along the outer circumference of the conductor segment for a preset length, and a pendant is suspended at the lower end of the thin wire, and the thin wire droops from the outer edge of the wire segment under the action of the pendant; the torque generated by the pendant on the wire segment with the axis as the rotation axis is equivalent to the torque of eccentric icing dispersed on the transmission line segment.

[0013] In a preferred embodiment of the present application, the ratio of the diameter of the conductive wire segment to the diameter of the thin wire is greater than a first threshold.

[0014] In a preferred embodiment of the present application, the ratio of the mass of the falling object to the mass of the thin line is greater than a second threshold.

[0015] In a preferred embodiment of the present application, a plurality of identical thin wires are evenly spaced apart on the conductor segment, the winding lengths and winding directions of the plurality of thin wires along the outer circumference of the conductor segment are the same, the fixed points of the plurality of thin wires on the conductor segment are located on the same straight line parallel to the axis, and an identical pendant is respectively hung at the lower ends of the plurality of thin wires to simulate uniform eccentric icing on the transmission line segment.

[0016] In a preferred embodiment of the present application, a plurality of identical thin wires are distributed at unequal intervals on the conductor segment, the winding lengths and winding directions of the plurality of thin wires along the outer circumference of the conductor segment are the same, the fixed points of the plurality of thin wires on the conductor segment are located on the same straight line parallel to the axis, and an identical pendant is hung at the lower ends of the plurality of thin wires respectively to simulate non-uniform eccentric icing on the transmission line segment.

[0017] In a preferred embodiment of the present application, the rotating shaft support mechanism includes at least two split rotating spacer bars arranged in parallel and opposite to each other, the conductor segment is arranged on a rotating wire clamp corresponding to a position of each split rotating spacer bar, the split rotating spacer bars are fixed by a connecting rod, and the connecting rod is arranged on a fixed wire clamp corresponding to a position of each split rotating spacer bar.

[0018] In a preferred embodiment of the present application, the rotating shaft support mechanism includes a suspension, on which at least two hollow pulleys are suspended by ropes, each hollow pulley is provided with a bearing, each bearing is sleeved on the conductor segment, the outer ring of the bearing is fixed relative to the hollow pulley, and the inner ring of the bearing is fixed relative to the conductor segment.

[0019] In a preferred embodiment of the present application, the length of the wire segment is within a second length range.

[0020] In a preferred embodiment of the present application, the conductor segment includes a rigid tube or a rigid column whose length is within a second length range, and the diameter of the rigid tube or the rigid column is equal to the diameter of the transmission conductor segment.

[0021] In a preferred embodiment of the present application, the falling object includes a weight.

[0022] It can be seen from the technical solutions provided in the above embodiments of the present application that the equivalent test device for eccentric icing of conductors in the embodiments of the present application includes: a conductor segment, which is used to simulate a transmission conductor segment, and the conductor segment is horizontally arranged on a rotating shaft support mechanism and can rotate freely relative to its own axis; a thin wire, the upper end of which is fixed to a fixed point of the conductor segment after being wound along the outer circumference of the conductor segment for a preset length, and a pendant is suspended at the lower end of the thin wire, and the pendant droops from the outer edge of the conductor segment under the action of the pendant; the torque generated by the pendant on the conductor segment with the axis as the rotation axis is equivalent to the torque of eccentric icing dispersed on the transmission conductor segment. The equivalent test device for eccentric icing of conductors in the embodiments of the present application provides a simple and quick means for quantitatively testing the performance parameters of conductors and hardware related to line dancing and eccentric icing, without consuming a lot of manpower, material resources and time to form actual eccentric icing of conductors, and has practical value for studying and solving the problem of line dancing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. In the drawings:

[0024] Figure 1a-Figure 1c It is a schematic diagram of common eccentric icing;

[0025] Figure 2 It is a schematic diagram of uniform ice coverage;

[0026] Figure 3 It is a structural schematic diagram of a split rotary spacer bar in the prior art;

[0027] Figure 4 This is a schematic diagram of a fan-shaped eccentric icing with an angle of 180° in one embodiment of the present application;

[0028] Figure 5This is a schematic diagram of torque integration of a fan-shaped eccentric icing with an angle of 180° in one embodiment of the present application;

[0029] Figure 6 It is a structural schematic diagram of an equivalent test device for eccentric icing of a conductor according to an embodiment of the present application;

[0030] Figure 7 It is a structural schematic diagram of an equivalent test device for eccentric icing of a conductor according to another embodiment of the present application;

[0031] Figure 8 A torque schematic diagram of an equivalent test device for eccentric icing of a conductor according to an embodiment of the present application;

[0032] Fig. 9 This is a test result of a wire rotation angle under the action of dispersed falling objects in one embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application. For example, in the following description, the second component is formed above the first component, which may include an embodiment in which the first component and the second component are formed in direct contact, and may also include an embodiment in which the first component and the second component are formed in non-direct contact (that is, additional components may be included between the first component and the second component), etc.

[0034] Moreover, for ease of description, some embodiments of the present application may use spatially relative terms such as "above", "below", "top", "below", etc. to describe the relationship between one element or component and another (or other) elements or components as shown in the various figures of the embodiments. It should be understood that in addition to the orientations described in the figures, the spatially relative terms are also intended to include different orientations of the device in use or operation. For example, if the device in the figures is turned over, the elements or components described as "below" or "beneath" other elements or components will subsequently be positioned as "above" or "on" the other elements or components.

[0035] In the process of realizing this application, the inventor of this application found that it is difficult to form eccentric icing that meets actual requirements under test conditions, which is one of the important factors that make it difficult to implement physical simulation of conductor eccentric icing tests. The following two difficulties are the main reasons why it is difficult to form eccentric icing that meets actual requirements under test conditions. Specifically:

[0036] Difficulty 1: Laboratory icing generally imitates the eccentric icing process of the conductor. Water mist is sprayed on one side of the conductor at an ambient temperature below 0°C, hoping that the water will form eccentric icing on that side of the conductor and cause the conductor to rotate. However, the actual result is not ideal. Most of the water will flow to the lower side of the conductor and condense into long icicles. These icicles cannot generate torque to rotate the conductor, but hinder the rotation of the conductor. The reasons for the inconsistency between laboratory icing and actual conductor eccentric icing are as follows: ① The icing of the actual transmission conductor comes from supercooled water vapor below 0°C in the atmosphere. This water vapor comes from the evaporation of ground water. It is pure water without condensation nuclei. Although the temperature is below 0°C, it still does not freeze when suspended in the atmosphere. Once these water vapors touch the side of the conductor under the horizontal wind, it is equivalent to touching the condensation nucleus, and instantly freeze on the windward side of the conductor without flowing on the conductor. This is why actual conductors can form eccentric icing. ② The water mist of the test room ice is sprayed from the nozzle to the side of the conductor. There will always be some impurities in the water that are equivalent to condensation nuclei. As long as the water temperature is lower than 0℃, it will freeze and block the nozzle, making the test unable to continue. In order to prevent the water from freezing prematurely, only water with a temperature slightly higher than 0℃ can be used. The temperature of the test room and the conductor is lower than 0℃. After the water is sprayed on the surface of the conductor, there is a process of temperature dropping from above 0℃ to below 0℃ and then freezing. Although this process is short, it is enough for the water to flow from the side of the conductor to the bottom and form icicles, resulting in the inconsistency between the ice morphology in the test room and the actual eccentric ice covering the conductor.

[0037] Difficulty 2: As mentioned above, a split rotary spacer is installed every 45m on the split conductor of the actual line, that is, the rotational resistance of each split rotary spacer corresponds to the torque generated by the eccentric icing of the 45m conductor, and at least two split rotary spacers are required in the test room to support the split conductor. Therefore, to test the rotational resistance of the split rotary spacer to the conductor, at least 90m of eccentric icing must be implemented on the conductor, but it is very difficult to find and use an icing test room that can accommodate 90m of conductor. The distance between the two iron towers of the line is generally 300m to 500m, so it is even more difficult to test the rotation performance of the suspension wire clamp or tension wire clamp on the iron tower to the first-stage conductor under the action of eccentric icing.

[0038] Since it is difficult to obtain actual eccentric icing on a long conductor that is not shorter than 90m, equivalent objects and equivalent methods can be considered to replace the actual eccentric icing, which can be used to analyze the anti-dancing effect of the split rotary spacer, and can also be used to test the resistance of the rotating wire clamp to eccentric icing. The equivalent method is "replacing the eccentric icing on the actual conductor with a falling object wrapped around the conductor". This equivalent method can conveniently "disperse the falling object around a conductor of the same length as the actual conductor (such as: 90m)" to be closer to the distributed eccentric icing condition on the actual long conductor; it can also "concentrate the falling object around a short conductor of several meters in length. Of course, the short conductor here can be replaced by a rigid tube or a rigid column, and the diameter of the rigid tube or rigid column is equal to the diameter of the transmission conductor" to facilitate testing in a small space. The equivalent and equivalent method should have a quantitative corresponding relationship with the actual eccentric icing, and the corresponding relationship is that the "falling object torque" is equal to the "eccentric icing torque dispersed on the long conductor".

[0039] For ease of understanding, the above equivalence principle is explained below.

[0040] It is well known to those skilled in the art that the product of force and the lever arm is the torque of the force about the axis of rotation. Figure 4 is a schematic diagram of eccentric icing on a conductor. The eccentric icing is simplified to a fan-shaped ring with an angle of 180°. O is the center line of the conductor and the rotation axis of the torque. O' is the center of gravity of the eccentric icing. OO' is the lever arm R1 of the eccentric icing. m1 is the mass of the eccentric icing on the conductor. g is the acceleration of gravity. The torque of the eccentric icing is M1 = m1g × R1. Figure 4 The eccentric icing center of gravity O' and the eccentric icing arm R1 are unknown, and the eccentric icing moment M1 cannot be directly calculated according to M1 = m1g × R1. After further research, the inventors of this application found that the eccentric icing moment M1 can be calculated according to Figure 5 As shown, the fan-shaped eccentric icing is differentiated into many small pieces of icing dθ, and the torque of the small pieces of eccentric icing on the conductor rotation axis is calculated separately. Then these small torques are added together to get the total eccentric icing torque. Obviously, this is an integration process.

[0041] The mass of a small piece of eccentrically covered ice:

[0042] The moment arm of a small piece of eccentric ice:

[0043] Total eccentric icing moment:

[0044]

[0045] Where: g is the acceleration due to gravity, h is the eccentric ice thickness, L is the wire length, ρ is the ice density, and R is the wire radius.

[0046] If a torque M2 equal to M1 is made, and M2 does not need to be actually covered with ice, nor does it need to be dispersed on the 90m conductor, then M2 can be used instead of M1 to conveniently analyze the anti-dancing effect of the split rotary spacer, and can also be used to test the resistance of the rotating wire clamp to eccentric ice. Similar to the windlass for drawing water from a well, the well rope is wound around the windlass, and the weight of the bucket can pull the well rope to turn the windlass, and the bucket can fall into the well. If the conductor is used as the windlass, the falling object is used as the bucket, and a thin wire is used instead of the well rope to be wound around the conductor, then M2 is made.

[0047] Based on the above principles, an embodiment of the present application provides an equivalent test device for eccentric icing of a conductor, which may include a conductor segment, a thin wire, and a falling object. Among them, the conductor segment can be used to simulate a transmission conductor segment, and the conductor segment can be horizontally arranged on a rotating shaft support mechanism, and can rotate freely relative to its own axis. The upper end of the thin wire can be fixed to a fixed point of the conductor segment after being wound along the outer circumference of the conductor segment for a preset length, and the falling object is suspended from the lower end of the thin wire; the lower end of the thin wire can droop from the outer edge of the conductor segment under the action of the falling object; the falling object can generate a torque on the conductor segment with the axis as the rotation axis, which can be equivalent to the torque of eccentric icing dispersed on the transmission conductor segment.

[0048] In the embodiment of the present application, the diameter of the thin wire is very small, and its diameter can be ignored relative to the diameter of the wire segment. In a specific implementation, the ratio of the diameter of the wire segment to the diameter of the thin wire can be greater than a specified threshold. In addition, the mass of the thin wire is very small, and its mass can be ignored relative to the mass of the falling object. In a specific implementation, the ratio of the mass of the falling object to the mass of the thin wire can also be greater than a specified threshold.

[0049] In addition, in some embodiments of the present application, the above-mentioned falling object can be, for example, a weight.

[0050] refer to Figure 8 As shown, in the equivalent test device for eccentric icing of a conductor in the embodiment of the present application, a falling object 5 can be suspended on a conductor segment 4 by a thin wire 4. Then the moment of the falling object 5 can be expressed as:

[0051] M2=m2g×R

[0052] Among them: m2 is the mass of the falling object 5, R is the radius of the wire segment 4, and is also the force arm of the falling object 5.

[0053] Let M1 = M2, we can get:

[0054] Using the formula The corresponding relationship between the thickness h of the eccentric ice coating and the mass m2 of the falling object can be obtained. In an exemplary embodiment, the corresponding relationship between the thickness h of the eccentric ice coating and the mass m2 of the falling object can be shown in the following Table 1. Assume that ρ=0.9 g / cm in the above formula 3 , R=13.6mm, L is the length of the wire segment, for example L=90m.

[0055] Table 1

[0056]

[0057]

[0058] In the equivalent test device for eccentric icing of conductors in the embodiment of the present application, the cleverness of using "falling objects wrapped around the conductor segment" instead of "eccentric icing on the conductor" lies in that the anti-dancing effect of the split rotary spacer is realized during the dynamic eccentric icing and rotation of the conductor. Although the conductor is rotating, the dynamic eccentric icing can always form a downward rotational torque on the windward side of the conductor and cause the conductor to continue to rotate; although the weight of the falling object is fixed, after being wrapped around the conductor with a thin rope, the falling object can always form a stable downward rotational torque on one side during the rotation of the conductor and cause the conductor to continue to rotate. This similar effect in the dynamic process is the main reason why "falling objects wrapped around the conductor segment" can replace "eccentric icing on the conductor".

[0059] In one embodiment of the present application, a plurality of identical thin wires may be distributed at equal intervals on the conductor segment, the winding lengths and winding directions of the plurality of thin wires along the outer circumference of the conductor segment are the same, the fixed points of the plurality of thin wires on the conductor segment are located on the same straight line parallel to the axis, and the lower ends of the plurality of thin wires are respectively hung with an identical pendant, so that uniform eccentric icing on the transmission line can be simulated. In another embodiment of the present application, a plurality of identical thin wires may be distributed at non-equal intervals on the conductor segment, the winding lengths and winding directions of the plurality of thin wires along the outer circumference of the conductor segment are the same, the fixed points of the plurality of thin wires on the conductor segment are located on the same straight line parallel to the axis, and the lower ends of the plurality of thin wires are respectively hung with an identical pendant, so that non-uniform eccentric icing on the transmission line can be simulated. In addition, since the cross-section of the eccentric icing may be a crescent shape, a D shape, or other approximate shapes, accordingly, as required, the corresponding relationship between the pendant and the eccentric icing may also be adjusted accordingly with the change of the icing shape.

[0060] In an exemplary embodiment of the present application, reference is made to Figure 6As shown, the shaft support mechanism may include at least two parallel and oppositely arranged split rotary spacer bars 6, and the conductor segment 1 may be correspondingly arranged on a rotary wire clamp 61 corresponding to a position of each split rotary spacer bar 6. One or more pendants 5 may be suspended on the conductor segment 1 through corresponding thin wires 4. The split rotary spacer bars 6 may be fixed by connecting rods 7 to maintain structural stability, and the connecting rods 7 may be arranged on fixed wire clamps 62 corresponding to a position of each split rotary spacer bar 6.

[0061] based on Figure 6 The equivalent test device for eccentric icing of the conductor shown in the figure can simulate the eccentric icing of the conductor in the positive and negative directions by changing the winding direction of the thin wire 4 on the conductor segment 1. The resistance of the rotating wire clamp of the split rotary spacer 6 to the conductor segment 1 is very different. When the thin wire 4 is wound in direction 1 (i.e., wind comes from the outside of the conductor and ice is formed), the mass of the falling object 5 reaches 13kg (equivalent to 4.4mm thick eccentric ice accumulated on the 90m conductor segment), and the conductor segment 1 is still difficult to rotate; while when the thin wire 4 is wound in direction 2 (i.e., wind comes from the inside of the conductor and ice is formed), the mass of the falling object 5 reaches 4kg (equivalent to 1.6mm thick eccentric ice accumulated on the 90m conductor segment), and the conductor segment 1 can rotate under the slight action of external force.

[0062] In addition, according to actual line operation experience, most conductor galloping occurs under relatively light ice coverage or even no obvious ice coverage, that is, 1 to several millimeters of eccentric ice coverage may cause galloping. Figure 6 The equivalent test results of the equivalent test device for eccentric icing of conductors shown in the figure indicate that the currently used split rotary spacers require eccentric icing of 4.4 mm and 1.6 mm or more in the positive and reverse directions respectively in order for the conductor to overcome the resistance of the rotating clamp and rotate. The eccentric icing in this thickness range may already cause line galloping, which is very likely one of the reasons why the current split rotary spacers are not effective in suppressing galloping. Therefore, it is necessary to improve the rotating clamp of the current split rotary spacers so as to reduce the rotational resistance on the split conductor to a state close to that of a single conductor without a spacer.

[0063] In order to verify the above viewpoints, in another exemplary embodiment of the present application, reference is made to Figure 7As shown, the shaft support mechanism includes a suspension 8, on which at least two hollow pulleys 9 can be suspended by ropes, each hollow pulley 9 can be provided with a bearing 10, and each bearing sleeve 10 can be on the conductor segment 1. One or more sinkers 5 can be suspended on the conductor segment 1 by corresponding thin wires 4, the outer ring of the bearing 10 can be fixed relative to the hollow pulley 9, and the inner ring of the bearing 10 can be fixed relative to the conductor segment 1. Since the bearing 10 in the hollow pulley 9 is flexible in rotation, the measurement of its rotation resistance to the conductor segment 1 can be used for comparison with the rotary clamp of the current split rotary spacer.

[0064] based on Figure 7 The equivalent test device for eccentric icing of the conductor shown in the figure shows that: only a falling object with a mass of 500g (equivalent to eccentric ice with a thickness of 0.18mm accumulated on a 90m conductor segment) is needed to make the conductor segment 1 clamped by the bearing 10 rotate flexibly, that is, the rotational resistance of the bearing 10 to the conductor segment 1 is much smaller than the rotating wire clamp of the current split rotary spacer bar. It can be seen that the rotational resistance of the rotating wire clamp of the current split rotary spacer bar to the conductor segment 1 still has a lot of room for improvement, that is, the current split rotary spacer bar still has a lot of room for improvement.

[0065] In addition, the equivalent test device for eccentric icing of the conductor in the embodiment of the present application can also be used to test the influence of the tension clamp or suspension clamp on the tower on the rotation angle of a conductor. For example, in an exemplary embodiment, the conductor segment is a single steel-core aluminum stranded wire with a diameter of D=21.4mm (i.e., radius R=10.7mm) and a length of 77m; the conductor segment is suspended horizontally with a tension of 20kN, and its two ends are fixed (even if the conductor segment cannot rotate), which is equivalent to the fixed clamping effect of the suspension clamp or the tension clamp; a pendant is suspended at intervals of 1m along the conductor segment, and a total of 76 pendants are suspended. Due to the limitations of the laboratory conditions, this test did not select the conductor segment length according to the 300m to 500m spacing between the two towers of the actual line. The specific tests are as follows:

[0066] ① The first group of tests: The mass of a single falling object is 250g, and the total mass is 250g*76=19000g, which is equivalent to a fan-shaped eccentric ice layer with a thickness of 7.2mm accumulated on the conductor segment. Fig. 9 As shown in curve 1, the rotation angle at both ends of the wire segment is 0°; extending from both ends to the middle of the wire segment, the rotation angle gradually increases; the rotation angle in the middle of the wire segment is the largest, reaching 24°.

[0067] ② The second group of tests: The mass of a single falling object is 550g, and the total mass is 550g*76=41800g, which is equivalent to a fan-shaped eccentric ice layer with a thickness of 11.7mm accumulated on the conductor segment. Fig. 9As shown in curve 2, the rotation angle at both ends of the wire segment is 0°; extending from both ends of the wire segment to the middle, the rotation angle gradually increases; the rotation angle in the middle of the wire segment is the largest, reaching 56°.

[0068] ③ As the amount of falling material increases (equivalent to the increase in the thickness of the eccentric ice covering the conductor), the rotation angle of the conductor segment increases accordingly. Fig. 9 As shown in Curve 1 and Curve 2, when the mass of the falling object is 19000g (equivalent to eccentric ice with a thickness of 7.2mm), the maximum rotation angle of the middle part of the conductor segment is 24°; when the mass of the falling object increases to 41800g (equivalent to eccentric ice with a thickness of 11.7mm), the maximum rotation angle of the middle part of the conductor segment increases accordingly to 56°.

[0069] The test shows that the limiting effect of the suspension clamps or tension clamps on the line towers on the rotation angle of the conductors cannot be ignored, resulting in uneven distribution of icing on the conductors between the two towers under dancing weather conditions - the icing on the conductors in the middle area is relatively uniform, while the eccentric icing on the conductors in the areas on both sides is relatively serious. This should be the second reason why the current split rotary spacer has poor effect in suppressing dancing.

[0070] The equivalent test device for eccentric icing of conductors in the embodiment of the present application has the following advantages:

[0071] 1. Good equivalence

[0072] The State Grid Corporation of China's standard "Technical Requirements for Split Rotary Spacers" Q / GDW718-2012 designed a test for the rotation flexibility of a rotating wire clamp to measure the rotation resistance of the rotating wire clamp to the conductor, requiring "the rotating wire clamp body to be fixed on the test machine, the wire clamp grips the rotating shaft of the test machine, the direction of the rotating shaft should be the same as the direction of gravity, and the torsional torque is gradually increased until the rotating wire clamp rotates, and the test force is recorded and the torque is calculated." There are two problems with this test method: (1) During the test, the direction of the rotating shaft of the rotating wire clamp is the same as the direction of gravity; while during actual operation, the direction of the rotating shaft of the rotating wire clamp is the same as the direction of the conductor, and is in a horizontal state, that is, the test method does not conform to the actual operating state and has poor equivalence. (2) There is no quantitative correspondence between the torque obtained in the test and the eccentric icing torque of the actual conductor. The conductor of the equivalent test device for eccentric icing of the conductor in the embodiment of the present application is consistent with the conductor operating conditions of the actual line, and there is a quantitative correspondence between the torque of the falling object and the eccentric icing torque of the actual conductor.

[0073] 2. Good stability

[0074] If actual eccentric icing is used in the test, it is not only difficult to obtain icing that meets the requirements, but also the stability of the icing is poor and it is difficult to maintain a constant state, which is not conducive to obtaining reliable test data; the equivalent test device for eccentric icing of the conductor in the embodiment of the present application can not only generate a torque similar to the actual eccentric icing on the conductor, but also the magnitude and direction of the torque can be automatically kept constant during the rotation of the conductor. This stability is of great significance for obtaining good test results and reliable test data.

[0075] 3. Good operability

[0076] In the equivalent test device for eccentric icing of conductors in the embodiment of the present application, falling objects are used to replace the eccentric icing of conductors in actual lines, thereby avoiding the problem of consuming a large amount of manpower, material resources and time to form actual eccentric icing; and the embodiment of the present application can use centralized falling objects to simulate eccentric icing of short conductors, and can also use dispersed falling objects to simulate eccentric icing of conductors of any length, which has good operability and is of great practical value for studying the anti-dancing performance of split rotary spacers and solving the problem of line dancing.

[0077] It should also be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a device or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such device or apparatus. In the absence of further restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the device or apparatus including the element.

[0078] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0079] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. An equivalent test device for eccentric icing of conductors, characterized in that: include: A conductor segment, used to simulate a transmission conductor segment, wherein the conductor segment is horizontally arranged on the rotating shaft support mechanism and can rotate freely relative to its own axis; A thin wire, wherein the upper end of the thin wire is fixed to a fixed point of the wire segment after being wound along the outer circumference of the conductor segment for a preset length, a pendant is suspended at the lower end of the thin wire, and the thin wire droops from the outer edge of the conductor segment under the action of the pendant; the torque generated by the pendant on the conductor segment with the axis as the rotation axis is equivalent to the torque of eccentric icing dispersed on the transmission conductor segment, the ratio of the diameter of the conductor segment to the diameter of the thin wire is greater than a first threshold value, so that the diameter of the thin wire is negligible relative to the diameter of the conductor segment, and the ratio of the mass of the pendant to the mass of the thin wire is greater than a second threshold value, so that the mass of the thin wire is negligible relative to the mass of the pendant.

2. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: A plurality of identical thin wires are evenly spaced on the conductor segment, the winding lengths and winding directions of the plurality of thin wires along the outer circumference of the conductor segment are the same, the fixing points of the plurality of thin wires on the conductor segment are located on the same straight line parallel to the axis, and an identical pendant is hung at the lower ends of the plurality of thin wires respectively to simulate uniform eccentric ice covering on the transmission line segment.

3. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: A plurality of identical thin wires are distributed at unequal intervals on the conductor segment, the winding lengths and winding directions of the plurality of thin wires along the outer circumference of the conductor segment are the same, the fixing points of the plurality of thin wires on the conductor segment are located on the same straight line parallel to the axis, and an identical pendant is hung at the lower end of each of the plurality of thin wires to simulate non-uniform eccentric icing on the transmission line segment.

4. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: The rotating shaft support mechanism includes at least two split rotating spacer bars arranged in parallel and opposite to each other, the conductor segment is arranged on a rotating wire clamp corresponding to a position of each split rotating spacer bar, the split rotating spacer bars are fixed by a connecting rod, and the connecting rod is arranged on a fixed wire clamp corresponding to a position of each split rotating spacer bar.

5. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: The rotating shaft support mechanism includes a suspension, on which at least two hollow pulleys are suspended by ropes, each hollow pulley is provided with a bearing, each bearing is sleeved on the conductor segment, the outer ring of the bearing is fixed relative to the hollow pulley, and the inner ring of the bearing is fixed relative to the conductor segment.

6. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: The length of the wire segment is within a second length range.

7. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: The conductor segment includes a rigid tube or a rigid column whose length is within a second length range, and a diameter of the rigid tube or the rigid column is equal to a diameter of the transmission conductor segment.

8. The equivalent test device for eccentric icing of conductors according to claim 1, characterized in that: The sinker includes a weight.

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