±1100kv ultra-high voltage dc transmission line 200kN level soft insulation pull rod

Abstract

The application discloses a 200kN-grade soft insulation pull rod for a +1100kV ultra-high voltage direct current transmission line, which comprises a force-bearing core rod, a sheath and a cut-preventing connector, the force-bearing core rod and the sheath are both woven by PBO fibers, rope sleeves are arranged at two ends of the force-bearing core rod, the cut-preventing connector comprises a pulley, connecting plates, anti-coming-off bolts and connecting bolts, the pulley is installed between the two connecting plates, a rope groove is arranged on the pulley, the anti-coming-off bolts are installed in anti-coming-off shaft holes, the connecting bolts are installed in connecting bolt holes, the rope sleeves are arranged on the rope groove, a PBO fiber moisture-proof treatment process is optimized, process time is greatly shortened, and the moisture-proof performance of a finished product is remarkably improved. The application has the advantages of simple structure, convenient installation and use, safety, light weight, high tensile strength, convenient transportation, superior moisture-proof performance, simple and safe operation method, greatly improved work efficiency and reduced labor intensity of workers.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of extra-high voltage line live maintenance tools, especially to a kind of ±1100kV extra-high voltage DC transmission line 200kN level soft insulation pull rod. BACKGROUND

[0002] In the live working technology research of extra-high voltage line, foreign countries such as Japan and Russia have carried out certain research relying on the actual high-voltage engineering of their own country. The live working of Japan has gradually developed towards mechanization and automation, and many electric power units have also carried out helicopter live maintenance operation projects. Russia has developed a complete and reasonable operation method for the live working of 330kV-750kV transmission lines, and is equipped with modern equipment and easy-to-use tools. The research on safety protection in live working is also relatively mature. However, due to various reasons, the power grids of these countries have not operated at the designed extra-high voltage level, so the research on the live working technology of extra-high voltage AC transmission lines has not been tested by long-term production practice, and the research results have been quite long. At the same time, there is no report on the research and application of soft insulation tools abroad.

[0003] Since the live working was carried out in China, dry wooden rods were initially used as the main insulation tool, and then epoxy glass steel was developed as the main insulation material. However, with the continuous development of live working, soft insulation materials such as high-performance high molecular fiber ropes have been widely used and become an important key material for the research and development of live working tools. Soft insulation tools are mainly made of organic materials, and now mainly include modified or improved materials such as nylon, silk, polyester and nylon. They all have good insulation performance and certain mechanical strength, but poor moisture resistance. In a humid state or during rain, the electrical performance decreases sharply until flashover and breakdown, directly endangering the personal safety and equipment safety of live working personnel. The ±1100kV Changji-Guquan line is the first DC ultra-high voltage transmission line with the highest voltage level in the world, and there is currently no related research on live working methods and tools.

[0004] The tensile strength and elastic modulus of PBO fiber (chemical name: poly-p-phenylene benzobisoxazazole, English name: Poly-p-phenylene benzobisoxazazole) are considered to be the ultimate modulus of linear polymer, and also have the performance of meta-aramid heat resistance and flame resistance. The limiting oxygen index is 68, it does not burn and does not shrink in the flame, and when impacted, the fiber can fibrillate a lot to absorb a lot of impact energy. The thermal decomposition temperature of PBO fiber is as high as 650℃, and it is considered to be the highest thermal stability organic fiber at present.

[0005] The Chinese patent document with the authorization publication number CN 205141518 U discloses a special high-voltage high-strength rainproof insulating pull rod. One end of an insulating core tube is connected with a double-hole single-ear connector, the insulating core tube is filled with foam, an HTV mixed rubber sleeve is arranged on the outer wall of the insulating core tube, the HTV mixed rubber sleeve is connected with the insulating core tube through a thickening agent, the other end of the insulating core tube is connected with a double-hole double-ear connector, and the double-hole single-ear connector and the double-hole double-ear connector are connected with the insulating core tube through a press connection. The insulating pull rod is safe and reliable, has high mechanical strength, large load capacity and rainproof and moisture-proof functions. The special high-voltage high-strength rainproof insulating pull rod is simple and feasible in use and can be used as a tool for replacing the insulating pull rod of a special high-voltage transmission line. The insulating pull rod in the document is a traditional hard insulating pull rod. The length of the hard insulating pull rod body under the special high-voltage level reaches 10 meters or more, which is not conducive to transportation, and the strength of the hard pull rod decreases with the increase of the length.

[0006] The Chinese patent document with the authorization publication number CN 203193180 U discloses an insulating soft pull rod for special high-voltage live working, which comprises a pull rod body, one end head is connected to each end of the pull rod body, the pull rod body is twisted by at least two soft fibers, and an outer composite insulating protective layer is arranged on the outer layer of the pull rod body. The pull rod body is made of soft fibers, so that the pull rod can be coiled according to needs, is convenient to transport, has high tensile strength, and the outer composite insulating protective layer arranged on the outer layer of the pull rod body makes the pull rod have better insulating performance and protects the soft fibers. The pull rod is suitable for the maintenance of a transmission line. However, the processing technology of the soft fibers in the invention is complex, time-consuming and laborious, and the moisture-proof performance of the processed soft fibers still cannot meet the requirements of the ultra-high voltage direct current transmission line. SUMMARY

[0007] Therefore, the purpose of the present application is to provide a ±1100kV special high-voltage direct current transmission line 200kN grade soft insulating pull rod, which is light in weight, high in tensile strength, convenient to transport, has superior moisture-proof performance, and is simple and safe to use and operate.

[0008] Our company has carried out a series of researches on improving the hydrophobicity or moisture-proof performance of PBO fibers, developed a process method for the surface activation and moisture-proof treatment of PBO fibers, and through continuous optimization and adjustment, invented a ±1100kV special high-voltage direct current transmission line 200kN grade soft insulating pull rod and applied it to the ±1100kV Changji-Guquan line special high-voltage direct current transmission line, which has superior moisture-proof performance. In addition, a matching anti-cut connector is designed, which is simple in structure, practical and has higher tensile strength.

[0009] In order to achieve the above object, the application adopts the following technical scheme: a 200kN-grade soft insulation pull rod for a ±1100kV ultra-high voltage direct current transmission line, comprising a load-bearing core rod, a sheath and a cut-resistant connector, the load-bearing core rod and the sheath are both woven by PBO fibers, the PBO fibers are subjected to moisture-proof treatment, the load-bearing core rod is externally sleeved with the sheath, the load-bearing core rod is provided with a rope sleeve at both ends, the cut-resistant connector comprises a pulley, a connecting sheet, an anti-escape bolt and a connecting bolt, the connecting sheet is in the shape of a rectangle, both ends are respectively provided with a pulley shaft hole and a connecting screw hole, and the middle part is provided with an anti-escape shaft hole, the pulley is provided with a rope groove, and the pulley is installed between the two connecting sheets through a pulley screw rod, a nut and the pulley shaft hole, the anti-escape bolt is installed in the anti-escape shaft hole, and the connecting bolt is installed in the connecting screw hole, and the rope sleeve is arranged on the rope groove of the pulley.

[0010] As a preferred structure of the application, the components of the cut-resistant connector are all made of high-strength titanium alloy material.

[0011] As a preferred structure of the application, both ends of the connecting sheet are semicircular, and each corner of the connecting sheet is subjected to round corner treatment.

[0012] As a preferred structure of the application, the distance between the anti-escape bolt and the bottom of the rope groove of the pulley is greater than the total diameter of the load-bearing pull rod and the sheath.

[0013] The moisture-proof treatment process of the PBO fibers in the application is as follows:

[0014] 1) After the C8 waterproof agent and the PBO fibers are added with water, they are boiled at 130 degrees for 30 minutes;

[0015] 2) After the PBO fibers are fished out, they are naturally air-dried, and then placed in an oven for drying at 170 degrees for 1 hour;

[0016] 3) After the PBO fibers are woven into the load-bearing core rod and the sheath, they are placed in an oven for drying at 140 degrees again for 30 minutes.

[0017] Further, the diameter of the load-bearing core rod is 25-30mm, the specific gravity is 0.8-0.9kg / m, and the breaking tension is greater than 500KN.

[0018] Further, the load-bearing core rod is 8-strand, and the rope sleeve is woven by the insertion method, which is an eight-strand chemical fiber insertion piper head weaving method.

[0019] Further, the load-bearing core rod and the sheath are respectively formed into rope sleeves by fixed clamps at both ends.

[0020] A method for replacing insulators of a 200kN-grade soft insulation pull rod for a ±1100kV ultra-high voltage direct current transmission line, comprising the following steps:

[0021] 1) Assembly tool:

[0022] a. Assemble the cross arm side fixture at the wire lifting position on the cross arm, and install the wire lifter firmly and accurately.

[0023] b. Use auxiliary tools such as pulley ropes to hoist the soft insulation pulling rod with hydraulic lead screw on the tower, and connect the upper and lower ends of the soft insulation pulling rod to the cross arm side fixture and the wire lifter installation hole respectively.

[0024] 2) Operation steps:

[0025] a. Tighten the hydraulic lead screw, and transfer the horizontal load of the insulator to the pulling rod to loosen the insulator;

[0026] b. Remove the spring pin;

[0027] c. Replace the insulator;

[0028] d. After replacement, loosen the hydraulic lead screw to transfer the load to the insulator, and the pulling rod is not under stress at this time;

[0029] e. Remove the pulling rod, lifter and fixture in turn, and the steps are opposite to the assembly steps.

[0030] The beneficial effects of the present application are:

[0031] 1. The soft insulation pulling rod is made of PBO fiber after moisture-proof treatment, has the characteristics of light weight, simple structure and easy operation, has no metal joint in the middle, meets the guarantee of effective length of live working, and can better optimize the design of extra-high voltage towers.

[0032] 2. The soft insulation pulling rod has the characteristics of bending and winding, which is convenient for transportation, saves operation time, reduces labor intensity of personnel, reduces the weight of tools, reduces operation risk, and improves the safety of work.

[0033] 3. The present application is composed of a load-bearing core rod, a sheath and a cut-resistant connector, has the advantages of few special parts, easy combination, convenient carrying, simple use, light weight and high safety factor, and is safe to use.

[0034] 4. The present application has simple structure, quick and safe operation method, shortens operation time and improves work efficiency.

[0035] 5. The PBO fiber used in the present application is modified by moisture-proof process, and the moisture-proof performance is improved by more than five times compared with the traditional process, which greatly improves the stability and safety of the insulation performance of the insulation pulling rod in a humid environment, especially meets the moisture-proof and insulation requirements in a ±1100kV extra-high voltage environment.

[0036] 6、The anti-cut connector assembly is made of high-strength titanium alloy material, lighter in weight and higher in tensile strength.

[0037] 7、The anti-loose bolt is installed in the anti-loose shaft hole, the middle part of the connecting piece is provided with an anti-loose shaft hole, the distance between the anti-loose bolt and the bottom of the rope groove of the pulley is greater than the diameter of the force-bearing pull rod and the sheath on the rope sleeve, the rope sleeve is arranged on the rope groove of the pulley, the anti-loose bolt plays a limiting and fixing role on the rope sleeve, so as to avoid the disengagement of the rope sleeve and the pulley, and the use is safe and the installation is convenient.

[0038] 8、The two ends of the connecting piece are semicircular, and the corners of the connecting piece are all rounded, so as to avoid that the connecting piece cuts the sheath and the force-bearing core rod.

[0039] 9、The PBO fiber moisture-proof treatment process is optimized, the process time is greatly shortened, and the moisture-proof performance of the finished product is significantly improved.

[0040] 10、The application has the advantages of simple structure, convenient installation and use, safety, greatly improved work efficiency and reduced labor intensity of workers.

[0041] 11、The force-bearing core rod is 8 strands, the rope sleeve is prepared by inserting method, the inserting method is an eight-strand fiber inserting biwa head weaving method, the rope sleeve weaving method does not need an additional metal fixing sleeve, and the fiber is not folded, the fiber is not damaged, the tensile strength of the force-bearing core rod can be maintained to the maximum extent, especially can meet the safety tensile requirement of 200kN level of ±1100kV extra-high voltage direct current transmission line. According to the safety factor 2.5, the minimum breaking tension of the insulating pull rod should be greater than 500kN, and the minimum breaking tension of the soft insulating pull rod in the application is 1000kN, which is much greater than the requirement. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a main structure schematic view of the first embodiment of the application;

[0043] Figure 2 It is an A-A section schematic view of the first embodiment of the application;

[0044] Figure 3 It is an anti-cut connector schematic view of the application;

[0045] Figure 4 It is a rope sleeve schematic view of the second embodiment of the application;

[0046] Figure 5 It is a tension sensor schematic view of the third embodiment of the application;

[0047] Numbers in the figure: 1-load-bearing core rod, 2-sheath, 3-anti-cut connector, 4-rope loop, 5-pulley, 6-connecting plate, 7-anti-slip bolt, 8-connecting bolt, 9-rope groove, 10-pulley screw, 11-fixing card, 12-tension sensor, 13-buzzer, 14-alarm indicator light, 15-wire. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0049] Example 1

[0050] like Figures 1-3 As shown, a 200kN-rated soft-insulated pull rod for ±1100kV UHVDC transmission lines comprises a load-bearing core rod 1, a sheath 2, and a cut-resistant connector 3. Both the core rod 1 and the sheath 2 are woven from PBO fibers treated for moisture resistance. The core rod 1 is tightly sheathed with a layer of sheath 2. The core rod 1 is a braided eight-strand cable structure with a diameter of 30mm. The combined diameter of the core rod 1 and sheath 2 is 32mm. The specific gravity is 0.88kg / m, and the limiting oxygen index is 68%. Rope loops 4 are installed at both ends of the core rod 1. These loops are braided using a splicing method similar to eight strands of synthetic fiber spliced ​​together like a pipa head. The measured breaking force of this soft-insulated pull rod is 1000kN, far exceeding the 200kN safety force requirement for ±1100kV UHVDC transmission lines.

[0051] The anti-cut connector 3 includes a pulley 5, a pulley screw 10, a connecting piece 6, an anti-slip bolt 7, and a connecting bolt 8. The connecting piece 6 is rectangular with semicircular ends. The corners of the connecting piece 6 are rounded to prevent the connecting piece 6 from cutting the sheath 2 and the load-bearing core rod 1. The connecting piece 6 has a pulley shaft hole and a connecting screw hole at each end, and an anti-slip shaft hole in the middle. The pulley is provided with a rope groove 9. The pulley 5 is mounted between the two connecting pieces 6 via the pulley screw 10, the nut, and the pulley shaft hole. The gap between the pulley 5 and the connecting piece 6 is less than 1 mm. The rope loop 4 is placed on the pulley 5 and located in the rope groove 9. The anti-slip bolt 7 is installed in the anti-slip shaft hole. The distance between the anti-slip bolt 7 and the bottom of the rope groove 9 of the pulley 5 is greater than the total diameter of the load-bearing rod 1 and the sheath 2 on the rope loop 4. The anti-slip bolt 7 serves to limit and fix the rope loop 4, preventing the rope loop 4 and the pulley 5 from separating, making it safe to use and easy to install. The connecting bolt 8 is installed in the connecting screw hole. When in use, the anti-cut connector 3 is fixed to the hydraulic screw through the connecting bolt 8. The components of the anti-cut connector 3 are made of high-strength titanium alloy material, which is lightweight and has high tensile strength. The total weight of the anti-cut connector 3 is 2.5 kg per piece. Each soft insulating pull rod is equipped with two anti-cut connectors 3.

[0052] The treatment process for improving the moisture-proof performance of the PBO fiber described in the present invention is as follows:

[0053] 1) Mix C8 waterproofing agent and water in a ratio of 1:10, put PBO fiber into the mixture and boil it at 130 degrees Celsius for 30 minutes.

[0054] 2) Take out the PBO fiber and dry it naturally, then place it in a 170 degree oven to dry for 1 hour;

[0055] 3) After the PBO fiber is woven into the load-bearing core rod and sheath, it is placed in an oven at 140 degrees and dried again for 30 minutes.

[0056] Our company has optimized the moisture-proof treatment process for PBO fibers. The process time is shortened by more than half compared with traditional methods. The moisture-proof performance of the treated PBO fibers is more than five times higher than that of traditional treatment methods. The insulation stability in humid environments is greatly improved, which greatly improves the safety of live insulator replacement work.

[0057] The invention is mainly used for replacing insulators of ±1100KV transmission line straight towers such as FXBZ-±1100 / 300-1 and FXBZ-±1100 / 420-1.

[0058] The supporting tools for use include cross arm side clamps, hydraulic screws and wire lifters, etc.

[0059] A method for using a 200 kN-class soft insulating pull rod for a ±1100 kV ultra-high voltage direct current transmission line comprises the following steps:

[0060] 1) Assembly tool:

[0061] a. Assemble the cross arm side fixture at the wire lifting position on the cross arm, and install the wire lifter firmly and accurately.

[0062] b. Use auxiliary tools such as pulley ropes to hoist the soft insulation pulling rod with hydraulic lead screw on the tower, and connect the upper and lower ends of the soft insulation pulling rod to the cross arm side fixture and the wire lifter installation hole respectively.

[0063] 2) Operation steps:

[0064] a. Tighten the hydraulic lead screw, transfer the horizontal load of the insulator to the pulling rod, and loosen the insulator;

[0065] b. Remove the spring pin;

[0066] c. Replace the insulator;

[0067] d. After replacement, loosen the hydraulic lead screw to transfer the load to the insulator, and the pulling rod is not under stress at this time;

[0068] e. Remove the pulling rod, lifter and fixture in turn, and the steps are opposite to the assembly steps.

[0069] The present application is composed of a load-bearing core rod, a sheath and a cut-resistant connector, has the advantages of few special parts, easy combination, convenient carrying, simple use, light weight and high safety factor, and the operation method is quick and safe, which shortens the operation time, improves the work efficiency and reduces the labor intensity of workers.

[0070] The soft insulation pulling rod used in the application is made of PBO fiber treated by moisture-proof process, has the characteristics of light weight, simple structure, high tensile strength, etc., has no metal joint in the middle, meets the guarantee of effective length of insulation for live-line work, and can better optimize the design of extra-high voltage towers. The soft insulation pulling rod has the characteristics of bending and winding, which is convenient for transportation, saves operation time, reduces labor intensity of personnel and tool weight, and reduces operation risk.

[0071] Example Two

[0072] As Figure 4 shown, the structure of the present embodiment and example one is basically the same, and the difference lies in that the load-bearing core rod 1 is formed into a rope sleeve 4 through a fixed card 11 at both ends, and the fixed card is an 8-shaped aluminum sleeve.

[0073] Example Three

[0074] As Figure 5As shown, the structure of the embodiment and the structure of the embodiment one are basically same, and the difference is that the tension sensor 12 is arranged outside the force core rod 1 and the sheath 2, the tension sensor 12 is a side pressure type tension sensor, the range is 500kN, and the overload alarm value is 300kN. The tension sensor is connected with the power supply and the handheld controller through the wire 15, the buzzer 13 and the alarm indicator 14 are arranged on the tension sensor, when the stress value of the soft insulation pull rod is greater than 300kN, the buzzer 13 and the alarm indicator 14 on the tension sensor 12 give out sound and light alarm, prompt the staff overload, and timely suspend the operation or effectively adjust, prevent accidents.

[0075] Embodiment four

[0076] The embodiment and the embodiment one are basically same, and the difference is that the C8 waterproof agent is mixed with water according to the proportion of 1:10, then the mixed solution is added into the dilute acetic acid, the dilute acetic acid concentration of the mixed solution is adjusted to 0.5ml / L, then the PBO fiber is put into the mixed solution and boiled at 130 degrees Celsius for 20 minutes. The waterproof agent is more stable under the weak acid condition, the PBO fiber is easier to handle, and the waterproof effect is more durable.

[0077] Finally, it is explained that the above embodiments are only used to illustrate the technical solutions of the present application, not to limit, and other modifications or equivalent replacements of the technical solutions of the present application made by the ordinary skilled in the art should be covered in the scope of the claims of the present application, as long as they do not deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. 200kN-class soft insulation pull rod for ±1100kV UHVDC transmission lines, characterized by: It includes a load-bearing core rod, a sheath and an anti-cut connecting head. The load-bearing core rod and the sheath are both woven from PBO fibers. The PBO fibers are moisture-proof treated. The outer surface of the load-bearing core rod is covered with a sheath. Rope loops are set at both ends of the load-bearing core rod. The anti-cut connecting head includes a pulley, a connecting plate, an anti-slip bolt and a connecting bolt. The connecting plate is rectangular in shape, with pulley shaft holes and connecting screw holes respectively set at both ends, an anti-slip shaft hole set in the middle, a rope groove set on the pulley, and the pulley is installed between the two connecting plates through a pulley screw, a nut and a pulley shaft hole. The anti-slip bolt is installed in the anti-slip shaft hole, the connecting bolt is installed in the connecting screw hole, and the rope loop is set on the rope groove of the pulley.

2. The 200 kN-class soft insulating pull rod for ±1100 kV UHVDC transmission lines according to claim 1, characterized in that: The components of the cut-resistant connector are all made of high-strength titanium alloy material.

3. The 200 kN-class soft insulating pull rod for ±1100 kV UHVDC transmission lines according to claim 1, characterized in that: Both ends of the connecting piece are semicircular, and all corners of the connecting piece are rounded.

4. The 200 kN-class soft insulating pull rod for ±1100 kV UHVDC transmission lines according to claim 1, characterized in that: The distance between the anti-drop bolt and the bottom of the rope groove of the pulley is greater than the total diameter of the load-bearing core rod and the sheath.

5. The 200 kN-class soft insulating pull rod for ±1100 kV UHVDC transmission lines according to claim 1, characterized in that: The PBO fiber moisture-proof treatment process is as follows: 1) Add water to C8 waterproofing agent and PBO fiber and boil at 130 degrees for 30 minutes; 2) Take out the PBO fiber and dry it naturally, then place it in an oven at 170 degrees for 1 hour; 3) After the PBO fiber is woven into the load-bearing core rod and sheath, it is placed in an oven at 140 degrees and dried again for 30 minutes.

6. A method for replacing insulators in a ±1100 kV UHVDC transmission line using a 200 kN-grade soft insulating pull rod according to any one of claims 1 to 5, characterized in that: The steps include: 1) Assembly tools: a. Assemble the crossarm side fixture at the wire lifting position on the crossarm, and install the wire lifter securely and ensure it is correct; b. Use pulleys and other auxiliary tools to hoist the soft insulating pull rod with a hydraulic screw onto the tower. Connect the upper and lower ends of the soft insulating pull rod to the crossarm side fixture and the conductor lifter mounting hole respectively; 2) Operation steps: a. Tighten the hydraulic screw to transfer the horizontal load of the insulator to the pull rod, so that the insulator relaxes; b. Remove the spring pin; c. Replace insulators; d. After the replacement is completed, loosen the hydraulic screw to transfer the load to the insulator. At this time, the pull rod is not under stress; e. Remove the pull rod, thread lifter, and clamp in sequence, following the reverse steps of the assembly process.

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