A split conductor based on small-section optical fiber composite sub-conductor

Abstract

The present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, comprising: an optical fiber composite sub-conductor with an optical fiber unit and at least two sub-conductors without an optical fiber unit; the cross-sectional area of ​​the optical fiber composite sub-conductor is smaller than the cross-sectional area of ​​each sub-conductor; when the number of sub-conductors is two, the optical fiber composite sub-conductor and the two sub-conductors are arranged in parallel in a plane according to a preset spacing, and the spacing between the optical fiber composite sub-conductor and the two sub-conductors is equal; when the number of sub-conductors is greater than two, each sub-conductor is arranged in parallel according to a preset spacing and passes through each vertex of a regular polygon vertically respectively, and the optical fiber composite sub-conductor passes through the center of the regular polygon and is parallel to each sub-conductor. The present application has the beneficial effects of significantly reducing the size of the excess cable reel and the joint box of the optical fiber composite sub-conductor and the occupied insulation space, reducing the number of excess cable reels and joint boxes, reducing the difficulty of engineering design and construction, and improving the safety of optical fiber communication under harsh conditions such as rain, snow and ice.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission, and in particular to a split conductor based on a small-section optical fiber composite sub-conductor. Background Art

[0002] Overhead transmission lines (referred to as lines) are an important part of the power grid. Lines generally have optical fiber communication functions. Among them, low-voltage distribution network lines such as 35kV generally only have overhead wires (referred to as wires) for transmitting electric energy, but no overhead ground wires (referred to as ground wires) for lightning protection. Therefore, an optical fiber composite phase line (OPPC) containing optical fiber units is generally used to replace one phase of conventional wires, and optical fiber communication functions are realized while transmitting electric energy; main power grid lines of 110kV (66kV) and above voltage levels generally have both wires and ground wires. Generally, an optical fiber composite overhead ground wire (OPGW) containing optical fiber units is used to replace a conventional ground wire, and optical fiber communication functions are realized while realizing lightning protection functions.

[0003] The disadvantages of using optical fiber composite overhead ground wire (OPGW) for main power grid lines of 110kV (66kV) and above voltage levels and the difficulties of using optical fiber composite phase line (OPPC) for main power grid lines of 110kV (66kV) and above voltage levels are analyzed as follows:

[0004] 1. Disadvantages of Optical Fiber Composite Overhead Ground Wire (OPGW)

[0005] OPGW has lightning protection function but no need to transmit electric energy, so its cross-sectional area is designed to be small, similar to the conventional ground wire, such as: 80mm 2 , 120mm 2 , much smaller than the cross-sectional area of ​​the conductor that transmits electrical energy, such as: 400mm 2 、630mm 2 、720mm 2 、810mm 2 OPGW with a small cross-section has obvious advantages in engineering design and construction, but it also has major disadvantages in operation. For example, ice covering under rainy, snowy and freezing weather conditions causes its tension and sag to increase, which can easily cause discharge between the conductor and OPGW, line tripping and line shutdown; and the small cross-sectional area of ​​OPGW and direct contact with the discharge arc cause its discharge point to heat up significantly, and the mechanical strength of this local area is greatly reduced. The combined effect of increased tension and decreased mechanical strength can easily cause OPGW to break, seriously threatening the safety of line operation and optical fiber communication.

[0006] 2. Difficulties of Optical Fiber Composite Phase Cable (OPPC)

[0007] Based on the above shortcomings of OPGW, it becomes a more reasonable alternative to fiber optic communication to combine the optical fiber unit in the conductor to form an optical fiber composite phase line (OPPC). The OPPC is generally applied to the split conductor of the main power grid line as follows: replace one sub-conductor of the split conductor with an OPPC, whose cross-sectional area (outer diameter), weight per unit length, stress-sag characteristics and other parameters are the same as other sub-conductors, and together with other sub-conductors, it forms a split conductor of one phase in a conventional arrangement. It is undeniable that since the cross-sectional area of ​​OPPC is the same as that of conventional sub-conductors, which is much higher than the cross-sectional area of ​​OPGW, the probability of OPPC disconnection and threat to the safety of fiber optic communication during operation, especially during ice disasters, can be greatly reduced; but for many years, there has been almost no progress in the promotion of OPPC in main power grid lines of 110kV (66kV) and above voltage levels, for the following reasons:

[0008] (1) The large insulation space occupied by the excess cable reel and joint box of OPPC is one of the obstacles to the promotion and application of OPPC. Similar to OPGW, the fiber optic fusion construction requires OPPC to retain a certain length of excess cable and wind it into a reel and fix it on the conductor side, generally hanging it on the lower side of the jumper insulator; after the fiber optic fusion is placed in the joint box, it must also be hung and fixed on the conductor side under the jumper insulator. ① OPGW is at ground potential as a whole, so its accessories such as excess cable reel and joint box are easy to fix on the ground wire bracket, etc.; and the cross-sectional area of ​​OPGW is small, and its excess cable reel diameter is small, so the insulation space occupied is also small, so it generally does not cause problems such as insufficient insulation distance of the line. ②OPPC is at high voltage potential as a whole, so its accessories such as cable drum and joint box can only be fixed on the conductor side, and the position and space available for fixing or hanging are limited; and the cross-sectional area (outer diameter) of OPPC is large, its cable drum diameter and weight are large, and the insulation space occupied is correspondingly large, so the cable drum and joint box of OPPC are hung on the conductor side below the jumper insulator, which may easily cause the insulation distance of the phase conductor to the tower to be insufficient when the wind deflects. This problem is particularly prominent for the OPPC transformation project of the operating line, so that the transformation difficulty and workload are too large, which is the biggest obstacle to the promotion of OPPC in the main power grid line.

[0009] (2) The difficulty and workload of OPPC construction are the second obstacle to the promotion and application of OPPC. The laying of OPGW is different from that of conventional ground wires. Each reel needs to be tensioned separately, and it cannot be laid out continuously with a joint tube like conventional ground wires. This results in the need to frequently switch the tension field and the traction field when laying out OPGW. The outer diameter of OPPC with power transmission function is much larger than that of OPGW, so the length of a reel of OPPC is smaller than that of a reel of OPGW. For example, OPGW can reach 5 km / reel, while OPPC can only reach 2-3 km / reel. This requires more frequent field switching when laying out OPPC, and leads to more fiber fusion splicing construction and more cable reels and joint boxes, making the construction difficulty and workload of OPPC much greater than that of OPGW, and increasing the maintenance workload after the line is put into operation.

[0010] Therefore, the problems of OPPC's spare cable drums and junction boxes occupying a large amount of insulation space, the large number of them, and the difficulty and workload of OPPC's laying out cables are technical issues that need to be solved urgently. Summary of the invention

[0011] In order to solve the defects in the prior art, the present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, which has the beneficial effects of significantly reducing the size and weight of the excess cable reel of the optical fiber composite sub-conductor, reducing the insulation space occupied by the excess cable reel and the junction box, reducing the number of excess cable reels and the junction boxes, greatly reducing the design and construction difficulty and workload of the project, promoting the application of optical fiber communication units in the split conductors of the main power grid overhead transmission lines, and improving the safety of power grid optical fiber communication under harsh conditions such as rain, snow and freezing.

[0012] In order to achieve the above-mentioned object, the present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, the split conductor based on a small-section optical fiber composite sub-conductor comprising: an optical fiber composite sub-conductor with an optical fiber unit and at least two sub-conductors without an optical fiber unit;

[0013] The cross-sectional area of ​​the optical fiber composite sub-conductor is smaller than the cross-sectional area of ​​each of the sub-conductors;

[0014] When the number of the sub-conductors is two, the optical fiber composite sub-conductor and the two sub-conductors are arranged in parallel in a plane according to a preset interval, and the interval between the optical fiber composite sub-conductor and the two sub-conductors is equal;

[0015] When the number of the sub-conductors is greater than two, the sub-conductors are arranged in parallel at a preset interval and pass perpendicularly through each vertex of a regular polygon, and the optical fiber composite sub-conductor passes through the center of the regular polygon and is parallel to each sub-conductor.

[0016] In one embodiment, the split conductor based on the small-section optical fiber composite sub-conductor further includes: a plurality of spacer rods;

[0017] The spacers are dispersedly arranged on the split conductor based on the small-section optical fiber composite sub-conductor according to preset intervals, and are used to maintain and fix the relative position and distance between the sub-conductors and the relative position and distance between the optical fiber composite sub-conductor and the sub-conductor.

[0018] In one embodiment, the stress-sag characteristic of the optical fiber composite sub-conductor is the same as the stress-sag characteristic of each of the sub-conductors; and the sag of the optical fiber composite sub-conductor is the same as the sag of each of the sub-conductors.

[0019] In one embodiment, the cross-sectional area of ​​the optical fiber composite sub-conductor is less than or equal to 15% of the sum of the cross-sectional areas of the sub-conductors and less than or equal to 120 mm 2 .

[0020] In one embodiment, the number of the sub-conductors includes: two, three, four, six or eight.

[0021] In one embodiment, the regular polygon includes: an equilateral triangle, a regular quadrilateral, a regular hexagon or a regular octagon.

[0022] In one embodiment, the split conductor based on the small-section optical fiber composite sub-conductor includes: a two-split conductor based on the small-section optical fiber composite sub-conductor, a three-split conductor based on the small-section optical fiber composite sub-conductor, a four-split conductor based on the small-section optical fiber composite sub-conductor, a six-split conductor based on the small-section optical fiber composite sub-conductor, or an eight-split conductor based on the small-section optical fiber composite sub-conductor.

[0023] The present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, comprising: an optical fiber composite sub-conductor with an optical fiber unit and at least two sub-conductors without an optical fiber unit; the cross-sectional area of ​​the optical fiber composite sub-conductor is smaller than the cross-sectional area of ​​each of the sub-conductors; when the number of the sub-conductors is two, the optical fiber composite sub-conductor and the two sub-conductors are arranged in parallel in a plane according to a preset spacing, and the spacing between the optical fiber composite sub-conductor and the two sub-conductors is equal; when the number of the sub-conductors is greater than two, each of the sub-conductors is arranged in parallel according to a preset spacing and passes through each vertex of a regular polygon perpendicularly respectively, and the optical fiber composite sub-conductor passes through the center of the regular polygon and is parallel to each of the sub-conductors. The present application arranges the optical fiber composite sub-conductor with a cross-sectional area much smaller than that of each sub-conductor at the center line position of the split conductor based on the small-section optical fiber composite sub-conductor. The optical fiber composite sub-conductor essentially only needs to provide the optical fiber communication function, and does not need to provide the conventional OPPC power transmission function. Therefore, under the premise that the mechanical strength and stress-sag characteristics meet the requirements, its cross-sectional area (outer diameter) can be equal to or even smaller than the optical fiber composite overhead ground wire (OPGW), thereby significantly reducing the size and weight of the excess cable drum of the optical fiber composite sub-conductor, reducing the insulation space occupied by the excess cable drum and the junction box, reducing the number of excess cable drums and junction boxes, greatly reducing the design and construction difficulty and workload of the project, promoting the application of optical fiber communication units in the split conductors of the main power grid overhead transmission line, and improving the safety of optical fiber communication under harsh conditions such as rain, snow and ice. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a structural schematic diagram of a split conductor (specifically, a four-split conductor) based on a small-section optical fiber composite sub-conductor of the present invention;

[0026] Figure 2 It is a schematic structural diagram of a two-splitting conductor based on a small-section optical fiber composite sub-conductor in one embodiment of the present invention;

[0027] Figure 3 It is a structural schematic diagram of a three-split conductor based on a small-section optical fiber composite sub-conductor in one embodiment of the present invention;

[0028] Figure 4 It is a schematic structural diagram of a six-split conductor based on a small-section optical fiber composite sub-conductor in one embodiment of the present invention;

[0029] Figure 5 It is a schematic structural diagram of a spacer rod of a four-split conductor based on a small-section optical fiber composite sub-conductor in one embodiment of the present invention;

[0030] Figure 6 It is a structural schematic diagram of a connecting plate of four split conductors based on small-section optical fiber composite sub-conductors in one embodiment of the present invention;

[0031] Figure 7 It is a structural schematic diagram of a split conductor based on a small-section optical fiber composite sub-conductor of the present invention used in an overhead power transmission line for preventing ice disasters, and the overhead power transmission line is in an anti-icing operation mode;

[0032] Figure 8 The invention is a schematic structural diagram of a split conductor based on a small-section optical fiber composite sub-conductor used in an overhead power transmission line for preventing ice disasters, wherein the overhead power transmission line is in a lightning protection operation mode. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The terms “first”, “second”, etc. used in this document do not particularly refer to an order or sequence, nor are they used to limit the present invention. They are only used to distinguish elements or operations described with the same technical terms.

[0035] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0036] As used herein, "and / or" includes any or all combinations of the items described.

[0037] Technical term explanation:

[0038] Bundled Conductor: A method of laying conductors to suppress corona discharge in high-voltage AC and DC transmission lines and reduce the reactance of AC transmission lines, equivalently increasing the conductor diameter and improving the transmission power. That is, each phase (or each pole) conductor is composed of several sub-conductors with smaller diameters, and each sub-conductor is spaced a certain distance apart and arranged in a regular polygon, and each sub-conductor is arranged at each vertex of the regular polygon.

[0039] Optical Phase Conductor (OPPC): A conductor that combines optical fiber units into a conductor to form a conductor that has the dual functions of transmitting electrical energy and optical fiber communication.

[0040] Overhead ground wire: A component used in overhead transmission lines to prevent lightning from directly striking the conductors. It is generally installed above or diagonally above the conductors. It is referred to as the ground wire, also known as the lightning arrester.

[0041] Optical Fiber Composite Overhead Ground Wire (OPGW): An optical fiber unit is composited into an overhead ground wire to form an overhead ground wire with the dual functions of line lightning protection and optical fiber communication.

[0042] Spacer: A component installed on the split conductor of an overhead transmission line to limit the relative movement between the sub-conductors of the split conductor and to maintain the geometric shape of the split conductor. Generally, a spacer is installed at a preset interval of tens of meters along the split conductor.

[0043] In view of the defects existing in the prior art, the present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, the structural schematic diagram of which is shown in FIG. Figure 1 As shown, the split conductor 1 based on the small-section optical fiber composite sub-conductor comprises: an optical fiber composite sub-conductor 2 with an optical fiber unit and at least two sub-conductors 3 without optical fiber units.

[0044] The cross-sectional area of ​​the optical fiber composite sub-conductor 2 is smaller than the cross-sectional area of ​​each of the sub-conductors 3. The cross-sectional area of ​​the optical fiber composite sub-conductor 2 is less than or equal to 15% of the sum of the cross-sectional areas of each of the sub-conductors and is less than or equal to 120 mm 2 .

[0045] like Figure 2 As shown, when there are two sub-conductors 3, the optical fiber composite sub-conductor 2 and the two sub-conductors 3 are arranged in parallel in a plane according to a preset spacing. The spacing between the optical fiber composite sub-conductor 2 and the two sub-conductors 3 is equal, so that the optical fiber composite sub-conductor 2 is arranged at the center line of the split conductor 1 based on the small-section optical fiber composite sub-conductor.

[0046] like Figure 1 , Figure 3 and Figure 4 As shown, when the number of the sub-conductors 3 is greater than two, each of the sub-conductors 3 is arranged in parallel according to a preset spacing and passes through each vertex of a regular polygon vertically. The optical fiber composite sub-conductor 2 passes through the center O of the regular polygon and is parallel to each of the sub-conductors 3, so that the optical fiber composite sub-conductor 2 is arranged at the center line of the split conductor 1 based on the small-section optical fiber composite sub-conductor.

[0047] The stress-sag characteristics of the optical fiber composite sub-conductor 2 are the same as those of each of the sub-conductors 3, so as to ensure that the sag of the optical fiber composite sub-conductor 2 is the same as that of each of the sub-conductors 3 under various operating conditions.

[0048] When implementing it, Figures 1 to 4 As shown, the number of the sub-conductors 3 includes: two, three, four, six or eight, but the present application is not limited thereto.

[0049] like Figures 1 to 4 As shown, corresponding to the number of the sub-conductors 3, the split conductors 1 based on the small-section optical fiber composite sub-conductors include: two-split conductors based on the small-section optical fiber composite sub-conductors, three-split conductors based on the small-section optical fiber composite sub-conductors, four-split conductors based on the small-section optical fiber composite sub-conductors, six-split conductors based on the small-section optical fiber composite sub-conductors, or eight-split conductors based on the small-section optical fiber composite sub-conductors, etc., but the present application is not limited thereto.

[0050] like Figure 1 , Figure 3 and Figure 4 As shown, the symmetrical regular polygon includes: a regular triangle, a regular quadrilateral, a regular hexagon or a regular octagon, etc., but the present application is not limited thereto.

[0051] When implementing it, Figure 1 As shown, the split conductor 1 based on the small-section optical fiber composite sub-conductor comprises: an optical fiber composite sub-conductor 2 with an optical fiber unit and four sub-conductors 3 without an optical fiber unit. The four sub-conductors 3 are spaced at a certain distance and arranged in a regular quadrilateral, and the four sub-conductors 3 are arranged at the vertices of the regular quadrilateral respectively, forming four split conductors. The optical fiber composite sub-conductor 2 is arranged on the center line of the four split conductors, forming four split conductors based on the small-section optical fiber composite sub-conductor. The optical fiber composite sub-conductor 2 only needs to meet the requirements of mechanical strength and stress-sag characteristics required for operation, and there is no quantitative requirement for its power transmission capacity and resistivity. Under the above premise, an optical fiber composite sub-conductor 2 with a cross-sectional area much smaller than that of the sub-conductor 3 can be selected to avoid the obvious change of electrical parameters of one phase or one pole conductor caused by adding the optical fiber composite sub-conductor 2 to the conventional split conductor. Take the four-split conductor based on small-section optical fiber composite sub-conductor composed of LGJ-400 / 35×4 four-split conductor and optical fiber composite sub-conductor with parameters close to OPGW-120 as an example: compared with the conventional four-split conductor without optical fiber composite sub-conductor, the four-split conductor based on small-section optical fiber composite sub-conductor has a reactance reduced by about 1%, a capacitance increased by about 1%, and a resistance reduced by about 7%, and if the skin effect of the alternating current is considered, the change in resistance is even smaller.

[0052] like Figure 2As shown, the split conductor 1 based on the small-section optical fiber composite sub-conductor comprises: an optical fiber composite sub-conductor 2 with an optical fiber unit and two sub-conductors 3 without an optical fiber unit. The two sub-conductors 3 are arranged at a certain distance and parallel to each other to form two split conductors. The optical fiber composite sub-conductor 2 is arranged on the center line of the two split conductors to form two split conductors based on the small-section optical fiber composite sub-conductor.

[0053] like Figure 3 As shown, the split conductor 1 based on the small-section optical fiber composite sub-conductor comprises: an optical fiber composite sub-conductor 2 with an optical fiber unit and three sub-conductors 3 without an optical fiber unit. The three sub-conductors 3 are spaced at a certain distance and arranged in an equilateral triangle, and the three sub-conductors 3 are arranged at the vertices of the equilateral triangle respectively, forming three split conductors. The optical fiber composite sub-conductor 2 is arranged on the center line of the three split conductors, forming a three split conductor based on the small-section optical fiber composite sub-conductor.

[0054] like Figure 4 As shown, the split conductor 1 based on the small-section optical fiber composite sub-conductor comprises: an optical fiber composite sub-conductor 2 with an optical fiber unit and six sub-conductors 3 without an optical fiber unit. The six sub-conductors 3 are spaced at a certain distance and arranged in a regular hexagon, and the six sub-conductors 3 are arranged at the vertices of the regular hexagon, forming six split conductors. The optical fiber composite sub-conductor 2 is arranged on the center line of the six split conductors, forming six split conductors based on the small-section optical fiber composite sub-conductor.

[0055] In one embodiment, the split conductor 1 based on the small-section optical fiber composite sub-conductor further includes: a plurality of spacer rods 4 .

[0056] Each of the spacer bars 4 is dispersedly arranged on the split conductor 1 based on the small-section optical fiber composite sub-conductor according to a preset interval, and is used to maintain and fix the relative position and distance between each of the sub-conductors 3 and the relative position and distance between the optical fiber composite sub-conductor 2 and the sub-conductor 3. Different from the spacer bars of conventional split conductors, the spacer bars 4 of the split conductor 1 based on the small-section optical fiber composite sub-conductor must add the fixing function of the optical fiber composite sub-conductor 2.

[0057] When implementing it, Figure 1 As shown, two spacers 4 are installed on a section of a four-split conductor 1 based on a small-section optical fiber composite sub-conductor. The distance between the two spacers 4 is generally tens of meters, for example, 45 meters. The structure of the spacer 4 is not unique. Any structure that can maintain and fix the relative position and distance between the optical fiber composite sub-conductor 2 and the sub-conductor 3 and the relative position and distance between each sub-conductor 3 can be used as the structure of the spacer 4, such as Figure 1As shown, the four vertices of the regular quadrilateral frame of the spacer 4 are respectively used to fix the four sub-conductors 3 of the four-split conductor 1 based on the small-section optical fiber composite sub-conductor; the midpoints of the two diagonals of the regular quadrilateral frame of the spacer 4 are used to fix the optical fiber composite sub-conductor 2. Among them, the diagonals of the regular quadrilateral frame are additional parts added on the basis of the conventional four-split conductor spacer, and are used to fix the optical fiber composite sub-conductor 2.

[0058] like Figure 2 As shown, two spacer bars 4 are installed on a section of a two-splitting conductor 1 based on a small-section optical fiber composite sub-conductor, and the distance between the two spacer bars 4 is generally tens of meters, for example: 45m. The two ends of the linear spacer bar 4 are respectively used to fix the two sub-conductors 3, which is a typical spacer bar structure of a conventional two-splitting conductor; the midpoint of the linear spacer bar 4 is used to fix the optical fiber composite sub-conductor 2, so that the relative position and distance between the optical fiber composite sub-conductor 2 and the sub-conductor 3 and the relative position and distance between each sub-conductor 3 are maintained and fixed.

[0059] like Figure 3 As shown, two spacers 4 are installed on a section of a three-split conductor 1 based on a small-section optical fiber composite sub-conductor, and the distance between the two spacers 4 is generally tens of meters, for example, 45 meters. The three vertices of the regular triangle frame of the spacer 4 are respectively used to fix the three sub-conductors 3 of the three-split conductor 1 based on the small-section optical fiber composite sub-conductor, and a center line is added to the regular triangle frame of the spacer 4 to fix the optical fiber composite sub-conductor 2, so that the relative position and distance between the optical fiber composite sub-conductor 2 and the sub-conductor 3 and the relative position and distance between each of the sub-conductors 3 are maintained and fixed.

[0060] like Figure 4 As shown, two spacers 4 are installed on a section of a six-split conductor 1 based on a small-section optical fiber composite sub-conductor, and the distance between the two spacers 4 is generally tens of meters, for example, 45 meters. The six vertices of the regular hexagonal frame of the spacer 4 are respectively used to fix the six sub-conductors 3 of the six-split conductor 1 based on the small-section optical fiber composite sub-conductor, and the midpoint of a diagonal line of the regular hexagonal frame of the spacer 4 is used to fix the optical fiber composite sub-conductor 2, so that the relative position and distance between the optical fiber composite sub-conductor 2 and the sub-conductor 3 and the relative position and distance between each of the sub-conductors 3 are maintained and fixed.

[0061] The general method of using a conventional optical fiber composite phase line (OPPC) for a split conductor of a main power grid line is to replace one sub-conductor in a conventional split conductor with one OPPC, that is, to use one OPPC and other sub-conductors without optical units in a conventional arrangement to form a split conductor of one phase or one pole. Therefore, the OPPC has both optical fiber communication function and power transmission function. The cross-sectional area (outer diameter) of the OPPC is the same as that of other sub-conductors in the split conductor, which is much larger than the optical fiber composite overhead ground wire (OPGW). The present invention arranges an optical fiber composite sub-conductor with a cross-sectional area much smaller than that of each sub-conductor at the center line position of the conventional split conductor to form a split conductor based on a small-section optical fiber composite sub-conductor. The small-section optical fiber composite sub-conductor actually only needs to have an optical fiber communication function, and does not need the power transmission function of the conventional OPPC. Therefore, under the premise that the mechanical strength and stress-sag characteristics meet the requirements, its cross-sectional area (outer diameter) can be equal to that of the OPGW, or even smaller. For example: the four split conductors are composed of 4 cross-sectional areas of 400mm 2 The cross-sectional area of ​​the optical fiber composite sub-conductor is only 120mm 2 or 80mm 2, install the optical fiber composite sub-conductor at the center line position of the four-split conductor to form a four-split conductor based on a small-section optical fiber composite sub-conductor. The advantages of the present invention are as follows: (1) The cross-sectional area (outer diameter) of the optical fiber composite sub-conductor is less than or equal to that of OPGW, so its cable drum weight and drum diameter are not greater than that of OPGW, occupying a small insulation space, and can be basically installed and accommodated within the scope of the split conductor, that is, the cable drum and joint box of the optical fiber composite sub-conductor are suspended on the conductor side below the jumper insulator, which will not cause problems such as insufficient insulation distance of the phase conductor to the iron tower. (2) The outer diameter of the optical fiber composite sub-conductor is less than or equal to that of OPGW, so the length of a drum of optical fiber composite sub-conductor can be no less than the length of OPGW, and the number of cable drums and joint boxes of the optical fiber composite sub-conductor of the entire line is no more than that of OPGW, which makes the construction difficulty and workload of the optical fiber composite sub-conductor (including tension pay-off, optical fiber fusion, etc.) the same as or even smaller than that of OPGW. (3) OPGW has a small outer diameter and is directly exposed to the outside and directly bears the high-temperature arc of discharge. Therefore, the probability of damage during operation, especially under severe rain, snow and freezing conditions, is high; although the outer diameter of the optical fiber composite sub-conductor of the present invention is equal to or smaller than that of the OPGW, it is placed in the center of the split conductor and is well shielded by the surrounding sub-conductors and is not easily directly burned by the high-temperature arc. Its operating safety is much higher than that of the OPGW. (4) The optical fiber composite sub-conductor of the present invention has substantially no power transmission requirements, that is, its aluminum strands only need to meet the requirements of mechanical properties and stress-sag properties, and do not need to achieve the excellent conductivity and power transmission capacity of other sub-conductors. In addition, the current skin effect of the surrounding sub-conductors makes the probability of short-circuit high current damaging the optical fiber composite sub-conductor during operation low. (5) The cross-sectional area (outer diameter) of the optical fiber composite sub-conductor of the present invention is much smaller than that of each sub-conductor. Therefore, adding the optical fiber composite sub-conductor on the basis of the original conventional split conductor has little effect on the parameters (including inductance, capacitance and resistance) of the original split conductor, that is, the effect on the balance of the three-phase parameters of the AC line and the balance of the two-pole parameters of the DC line can be ignored.

[0062] Compared with OPGW, the present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, which improves the optical fiber communication safety of overhead transmission lines under adverse conditions such as rain, snow and ice; compared with conventional OPPC, the optical fiber composite sub-conductor of the present invention greatly reduces the difficulty and workload of engineering design, construction and operation and maintenance, which is conducive to the application of optical fiber communication units in the split conductors of overhead transmission lines of the main power grid.

[0063] Application Scenario

[0064] Figure 5 The schematic diagram is a structural diagram of a spacer rod 4 of a four-split conductor based on a small-section optical fiber composite sub-conductor. Figure 5As shown, the pre-twisted wire clamp 5 is used to connect and fix the optical fiber composite sub-conductor 2, and the connecting plate 6 is detachable to facilitate the installation of the optical fiber composite sub-conductor 2 at the center of the four-split conductor. The present application is not limited to the structure of the spacer rod 4.

[0065] Figure 6 The structure diagram of the connecting plate 12 is a four-split conductor based on a small-section optical fiber composite sub-conductor. Figure 6 As shown, on the line tower (straight line tower), a connecting plate 12 is needed to suspend the split conductor 1 based on the small-section optical fiber composite sub-conductor on the line tower, and to maintain and fix the relative position and distance between the optical fiber composite sub-conductor 2 and each sub-conductor 3. The pre-twisted wire clamp 13 is used to connect and fix the optical fiber composite sub-conductor 2, and the connecting plate 14 is detachable to facilitate the installation of the optical fiber composite sub-conductor 2 at the center of the four split conductors. The present application is not limited to the structure of the connecting plate 12.

[0066] Figure 7 The present invention is a schematic diagram of a structure of a split conductor based on a small-section optical fiber composite sub-conductor used in an overhead power transmission line to prevent ice disasters. Figure 7 As shown, the overhead transmission line is in anti-icing operation mode. Figure 8 The present invention is a schematic diagram of a structure of a split conductor based on a small-section optical fiber composite sub-conductor used in an overhead power transmission line to prevent ice disasters. Figure 8 As shown in Figure 1, the overhead transmission line is in lightning protection operation mode. Figure 7 and Figure 8 As shown, the split conductor 1 based on the small-section optical fiber composite sub-conductor replaces the conventional split conductor of one phase of the overhead power transmission line, and it has both power transmission function and optical fiber communication function. The spacer 4 and the connecting plate 12 are used to fix and maintain the shape and size of the split conductor 1 based on the small-section optical fiber composite sub-conductor. The overhead ground wire 7 of the overhead power transmission line is a conventional ground wire without an optical fiber unit, which has a lightning protection function but does not have an optical fiber communication function. The overhead ground wire 7 is connected to the line tower 11 in an open tension mode through the ground wire tension insulator 8, wherein the electrical parameters of the ground wire tension insulator 8 (excluding the atmospheric overvoltage parameters) are not less than the electrical parameters of the conductor insulator 9.

[0067] like Figure 7As shown, under rainy, snowy and freezing weather conditions where ice disasters may occur, the ground wire jumper 10 connecting the line tower 11 and the overhead ground wire 7 is disconnected, the overhead ground wire 7 is at a floating potential, and the overhead transmission line is in an anti-icing operation mode. At this time, if ice covers the conductor (including the split conductor 1 based on the small-section optical fiber composite sub-conductor) and the overhead ground wire 7 to be close to or even in contact with each other, discharge between the conductor (including the split conductor 1 based on the small-section optical fiber composite sub-conductor) and the ground wire 7 will not occur, and accordingly, subsequent ground wire disconnection and tower collapse due to discharge are avoided, thereby improving the safety of line operation and the safety of optical fiber communication under rainy, snowy and freezing weather conditions.

[0068] like Figure 8 As shown, under non-rain, snow and freezing weather conditions such as thunderstorm season, a ground jumper 10 is used to connect the line tower 11 and the overhead ground wire 7. The overhead ground wire 7 is at or close to the ground potential and has a conventional lightning protection function. The overhead transmission line is in a lightning protection operation mode.

[0069] Compared with the optical fiber composite overhead ground wire (OPGW), the advantages of the split conductor based on the small-section optical fiber composite sub-conductor provided by the present invention are as follows:

[0070] 1. Improve the safety of optical fiber communication. When a conductor-ground wire discharge or other forms of discharge occur, the OPGW has a small cross-sectional area and is directly exposed to the outside and directly subjected to high-temperature arc burning, which can easily cause the OPGW to break or disconnect, threatening the safety of optical fiber communication. Although the cross-sectional area (outer diameter) of the optical fiber composite sub-conductor of the present invention is equal to or smaller than that of the OPGW, it is placed in the center of the split conductor and is well shielded by the surrounding sub-conductors and is not easily directly burned by high-temperature arcs. The operating safety is much higher than that of the OPGW, which effectively improves the safety of optical fiber communication of overhead power transmission lines under severe weather conditions such as rain, snow and ice.

[0071] 2. Make the anti-icing operation mode based on overhead ground wires operational, and improve the safety of line operation under rainy, snowy and freezing weather conditions. At present, main power grid lines of voltage levels of 110kV (66kV) and above generally use at least one OPGW, and the optical fiber unit of OPGW must maintain a continuous state throughout the line, while the anti-icing operation mode of the above-mentioned overhead transmission lines requires that the ground wire be divided into multiple discontinuous sections, so the line using OPGW is not suitable for the above-mentioned anti-icing operation mode; the split conductor based on small-section optical fiber composite sub-conductor of the present invention has a power transmission function and an optical fiber communication function at the same time, so the overhead ground wire of the line can use a conventional ground wire without an optical fiber unit without using an OPGW, so that the line can implement the above-mentioned anti-icing operation mode based on the overhead ground wire, which improves the safety of line operation under rainy, snowy and freezing weather conditions.

[0072] Compared with the existing optical fiber composite phase line (OPPC), the split conductor based on the small-section optical fiber composite sub-conductor provided by the present invention has the following advantages:

[0073] 1. The optical fiber composite sub-conductor will not cause the insufficient insulation distance between the conductor and the iron tower. The diameter of the remaining cable drum of the optical fiber composite sub-conductor is small, and the insulation space occupied by the remaining cable drum and the joint box is small. Therefore, when the remaining cable drum and the joint box are installed and fixed on the conductor side, they can basically be accommodated within the range of the split conductor, and will not cause the insufficient insulation distance between the conductor and the iron tower.

[0074] 2. The construction difficulty and workload of optical fiber composite sub-conductors are greatly reduced, and will not cause serious attenuation of optical signals:

[0075] ① The cross-sectional area (outer diameter) of the optical fiber composite sub-conductor is not greater than that of the OPGW, that is, the length of a reel of optical fiber composite sub-conductor and its single tension pay-off length are not less than that of the OPGW. Therefore, the number of tension pay-offs of the optical fiber composite sub-conductor of the entire line is not greater than that of the OPGW, which is much smaller than that of the conventional OPPC.

[0076] ② Since the length of a reel of optical fiber composite sub-conductor is not less than OPGW, the number of its remaining cable reels and joint boxes within the entire line is no more than OPGW, but much less than conventional OPPC, that is, the amount of optical fiber fusion construction of the optical fiber composite sub-conductor and the installation construction of the joint box and the remaining cable reel are much less than conventional OPPC.

[0077] ③ Since the number of optical fiber joints of the optical fiber composite sub-conductor is small, it will not cause serious attenuation of the optical signal. In summary, compared with the conventional OPPC, the optical fiber composite sub-conductor of the present invention has greatly reduced construction difficulty and workload, and will not cause serious attenuation of the optical signal.

[0078] The present invention provides a split conductor based on a small-section optical fiber composite sub-conductor, comprising: an optical fiber composite sub-conductor with an optical fiber unit and at least two sub-conductors without an optical fiber unit;

[0079] The cross-sectional area of ​​the optical fiber composite sub-conductor is smaller than the cross-sectional area of ​​each sub-conductor; when the number of the sub-conductors is two, the optical fiber composite sub-conductor and the two sub-conductors are arranged in parallel in a plane according to a preset spacing, and the spacing between the optical fiber composite sub-conductor and the two sub-conductors is equal; when the number of the sub-conductors is greater than two, each sub-conductor is arranged in parallel according to a preset spacing and passes through each vertex of a regular polygon vertically, and the optical fiber composite sub-conductor passes through the center of the regular polygon and is parallel to each sub-conductor. The present invention has the beneficial effects of significantly reducing the size and weight of the excess cable drum of the optical fiber composite sub-conductor, reducing the insulation space occupied by the excess cable drum and the junction box, greatly reducing the design, construction difficulty and workload of the project, promoting the application of optical fiber communication units in the split conductors of the main power grid overhead transmission line, and improving the safety of optical fiber communication under harsh conditions such as rain, snow and ice.

[0080] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0081] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A split conductor based on a small-section optical fiber composite sub-conductor, characterized in that: include: An optical fiber composite sub-conductor having an optical fiber unit and at least two sub-conductors without optical fiber units; The cross-sectional area of ​​the optical fiber composite sub-conductor is smaller than the cross-sectional area of ​​each of the sub-conductors; When the number of the sub-conductors is two, the optical fiber composite sub-conductor and the two sub-conductors are arranged in parallel in a plane according to a preset interval, and the interval between the optical fiber composite sub-conductor and the two sub-conductors is equal; When the number of the sub-conductors is greater than two, the sub-conductors are arranged in parallel at a preset interval and respectively pass through each vertex of a regular polygon perpendicularly, and the optical fiber composite sub-conductor passes through the center of the regular polygon and is parallel to each sub-conductor; The stress-sag characteristic of the optical fiber composite sub-conductor is the same as the stress-sag characteristic of each of the sub-conductors; and the sag of the optical fiber composite sub-conductor is the same as the sag of each of the sub-conductors.

2. The split conductor based on the small-section optical fiber composite sub-conductor according to claim 1, characterized in that: Also includes: Multiple spacer bars; The spacers are dispersedly arranged on the split conductor based on the small-section optical fiber composite sub-conductor according to preset intervals, and are used to maintain and fix the relative position and distance between the sub-conductors and the relative position and distance between the optical fiber composite sub-conductor and the sub-conductor.

3. The split conductor based on the small-section optical fiber composite sub-conductor according to claim 1, characterized in that: The cross-sectional area of ​​the optical fiber composite sub-conductor is less than or equal to 15% of the sum of the cross-sectional areas of the sub-conductors and less than or equal to 120 mm 2 .

4. The split conductor based on the small-section optical fiber composite sub-conductor according to claim 1, characterized in that: The number of the sub-conductors includes: two, three, four, six or eight.

5. The split conductor based on the small-section optical fiber composite sub-conductor according to claim 1, characterized in that: The regular polygon includes: an equilateral triangle, a regular quadrilateral, a regular hexagon or a regular octagon.

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