Composite core cable and manufacturing method thereof

Abstract

The invention discloses a composite core cable and a manufacturing method thereof. The manufacturing method comprises the following steps: pulling a carbon fiber bundle and a glass fiber bundle to pass through a fiber bundle guider to enter a dipping tank for full dipping; the carbon fiber bundles and the glass fiber bundles are pulled to leave the dipping tank and enter a first drying oven; the carbon fiber bundles and the glass fiber bundles are pulled to leave the first oven and enter a second oven; the carbon fiber bundle and the glass fiber bundle are pulled to leave the second drying oven and enter the progressive drying oven, and a plurality of optical fibers are pulled to enter the progressive drying oven; the carbon fiber bundles, the glass fiber bundles and the optical fibers are pulled to leave the progressive oven and enter a post-curing oven to form a core material, the core material comprises an inner core, an outer core and a plurality of optical fibers, the inner core is carbon fiber / epoxy resin, the outer core is glass fiber / epoxy resin, the outer core surrounds the periphery of the inner core, and the optical fibers are located in the inner core and / or the outer core. The actual use temperature limit up to 230 DEG C can be realized, and the current-carrying capacity can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cable preparation, in particular to a composite core cable and a manufacturing method thereof. BACKGROUND

[0002] With the continuous development of power transmission and communication technology, higher requirements are put forward for the performance of cable materials. Traditional metal core cables, such as ACSR cables (aluminum clad steel core aluminum stranded wire), are limited in application in high-voltage transmission lines, aerospace and special environments due to their large weight, low strength, easy corrosion and other problems. Especially in the operating temperature range of 90℃ to 230℃, the corresponding sag phenomenon occurs due to annealing of the steel core, which not only affects the safety and stability of the cable, but also limits the power transmission efficiency. Therefore, a cable that can withstand higher load flow without excessive sag is needed. SUMMARY

[0003] To this end, it is necessary to provide a composite core cable and a manufacturing method thereof, and a cable that can withstand higher load flow without excessive sag is needed.

[0004] To achieve the above-mentioned purpose, the inventors provide a composite core cable manufacturing method, comprising the following steps:

[0005] The carbon fiber bundle and the glass fiber bundle are pulled through the fiber bundle guide into the impregnation tank for sufficient impregnation, and the impregnation tank is filled with a mixed solution formed by 100 parts of epoxy resin, 125 parts of curing agent, 7 parts of modifier and 10 parts of filler, and the refractive index of the mixed solution is 1.50-1.58;

[0006] The carbon fiber bundle and the glass fiber bundle are pulled out of the impregnation tank and into the first oven for preheating, compaction and removal of moisture in the carbon fiber bundle and the glass fiber bundle;

[0007] The carbon fiber bundle and the glass fiber bundle are pulled out of the first oven and into the second oven, and the carbon fiber bundle and the glass fiber bundle are compressed and shaped with the bushing;

[0008] The carbon fiber bundle and the glass fiber bundle are pulled out of the second oven and into the progressive oven, and a plurality of optical fibers are also pulled into the progressive oven, and the carbon fiber bundle, the glass fiber bundle and the optical fibers are preliminarily cured;

[0009] The carbon fiber bundle, the glass fiber bundle and the optical fibers are pulled out of the progressive oven and into the post-curing furnace to form a core material, the core material includes an inner core, an outer core and a plurality of optical fibers, the inner core is carbon fiber / epoxy resin, the outer core is glass fiber / epoxy resin, the outer core surrounds the outer periphery of the inner core, and the optical fibers are located in the inner core and / or the outer core.

[0010] Further, the following steps are also included:

[0011] The voids and damages of the core material are captured by an optical time domain reflectometer and optical fibers.

[0012] Further, the optical fibers are two, one of which is arranged in the outer core and at the 6 o'clock and 12 o'clock positions, and the other of which is arranged in the inner core.

[0013] Further, the method further comprises the following steps:

[0014] The core material is pulled out of the post-curing oven and into a contaminant extraction system;

[0015] The core material is pulled out of the contaminant extraction system and into a cooling system, and waits for the temperature of the core material to drop to room temperature.

[0016] Further, the method further comprises the following steps:

[0017] The aluminum segments are wound around the core material to form a first aluminum conductor surrounding the outer periphery of the outer core and a second aluminum conductor surrounding the outer periphery of the first aluminum conductor.

[0018] Further, the viscosity of the epoxy resin is 200 cP to 1500 cP;

[0019] The tensile strength of the carbon fibers in the carbon fiber bundle is 350 Ksi to 750 Ksi, and the elastic modulus is 22 Msi to 37 Msi, and the tensile strength of the glass fibers in the glass fiber bundle is 180 Ksi to 220 Ksi, and the elastic modulus is 6 Msi to 7 Msi;

[0020] Further, the diameter of a single carbon fiber is 5 um to 10 um, and the diameter of a single glass fiber is 8 um to 15 um.

[0021] Further, the heating temperature in the first oven and the second oven is 150℉ to 250℉;

[0022] The heating temperature in the gradual oven is 330℉ to 370℉;

[0023] The heating temperature in the post-curing oven is 400℉.

[0024] Further, the diameter of the core material is 5 mm to 10.5 mm.

[0025] To achieve the above-mentioned purposes, the inventors also provide a composite core cable made by the composite core cable manufacturing method of any one of the above-mentioned embodiments.

[0026] Compared with the prior art, the above-mentioned technical solutions have the following beneficial effects:

[0027] By employing an aluminum conductor composite core reinforced cable, an increase in ampacity can be achieved. This reinforced composite core cable is a high temperature, low sag conductor that can operate at temperatures in excess of 100°C while maintaining stable tensile strength and creep elongation properties, allowing for a practical use temperature limit of up to 230°C. The composite core cable can operate reliably for approximately sixty years, and more preferably, seventy years, without the need to increase the outer diameter of the composite core or conductor. Using the same diameter as a traditional ACSR cable, the composite reinforced cable can increase the line capacity by 50% at 180°C without a significant impact on the structural load. This provides physical space for more aluminum material without increasing the weight of the conductor and meets the requirements for sag limitations in mechanical and physical properties, allowing for more efficient and reliable power transmission.

[0028] The above summary of the invention is only a summary of the technical solutions of the present application. In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, and further enable the implementation of the contents recorded in the specification and drawings, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more easily understood, the following will be described in combination with the specific embodiments of the present application and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings are only used to show the principles, implementation manners, applications, characteristics and effects of the specific embodiments of the present application and other related contents, and cannot be considered as limitations of the present application.

[0030] Figure 1 A flow chart for preparing the composite core cable in the present embodiment;

[0031] Figure 2 A schematic diagram of the composite core cable in the present embodiment;

[0032] Figure 3 A cross-sectional view of the composite core cable in the present embodiment;

[0033] Figure 4 A schematic diagram of the fiber bundle guide in the present embodiment;

[0034] Figure 5 A schematic diagram of the oven in the present embodiment;

[0035] Figure 6 A schematic diagram of the distribution of carbon fiber bundles in the present embodiment;

[0036] Figure 7 A schematic diagram of the bushing in the present embodiment.

[0037] Explanation of reference signs:

[0038] 1. Winder; 2. Fibre tow; 3. Spindle; 4. Fibre tow guide; 5. Creel; 6. Dip tank; 7. First oven; 8. Second oven; 9. Progressive oven; 10. Post curing oven; 11. Contaminant extraction system; 12. Cooling system; 13. Take-up device; 14. Optical fibre supply; 15. Passage 1; 16. Passage 2; 17. Bushing; 18. Cylindrical portion;

[0039] A. Optical fibre; B. Inner core; C. Outer core; D. First aluminium conductor; E. Second aluminium conductor. DETAILED DESCRIPTION

[0040] To make the possible application scenarios, technical principles, specific implementation schemes, and the purposes and effects of the present application clear, the following will be described in detail in combination with the specific embodiments listed and the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical schemes of the present application, and therefore cannot be used to limit the protection scope of the present application.

[0041] In this text, the term “embodiment” means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The term “embodiment” appearing at various positions in the specification does not necessarily refer to the same embodiment, and does not particularly limit the independence or association between other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the technical features mentioned in each embodiment can be combined in any way to form a corresponding implementable technical scheme.

[0042] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0043] In the description of the present application, the word “and / or” is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character “ / ” herein generally represents that the associated objects before and after are a “or” logical relationship.

[0044] In the present application, terms such as “first” and “second” are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.

[0045] In the present application, the terms "comprise", "contain", "include", or other similar phrases used in the description means to encompass the non-exclusive inclusion, and the terms do not exclude the presence of additional elements in the process, method or product comprising the elements, so that the process, method or product comprising a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include the elements inherent to such process, method or product.

[0046] In the present application, the terms "comprise", "contain", "include", or other similar phrases used in the description means to encompass the non-exclusive inclusion, and the terms do not exclude the presence of additional elements in the process, method or product comprising the elements, so that the process, method or product comprising a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include the elements inherent to such process, method or product.

[0047] In the description of the embodiments of the present application, the spatial-related terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. The indicated orientation or position relationship is based on the orientation or position relationship shown in the specific embodiment or the drawing, and is only for the convenience of describing the specific embodiments of the present application or for the reader to understand, and does not indicate or imply that the indicated device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0048] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "mount", "connect", "connect", "fix", "set", etc. should be understood in a broad sense. For example, the "connection" can be a fixed connection, or a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0049] Please refer to Figures 1 to 7 The present embodiment provides a composite core cable manufacturing method, comprising the following steps:

[0050] Fiber impregnation: The carbon and glass fiber tows are drawn through the tow guides 4 into the impregnation tank 6 where they are thoroughly wetted by a solution of 100 parts epoxy resin, 125 parts curing agent, 7 parts modifier, and 10 parts filler to form a mixture having a refractive index of 1.50 to 1.58. The modifier is added to maintain the viscosity of the final mixture during the manufacturing process.

[0051] The proper ratio of the four components, epoxy resin, curing agent, modifier, and filler, is used to achieve the proper refractive index of the epoxy resin, i.e., 1.50 to 1.58. A lower refractive index means that the epoxy resin is in a lower proportion in the mixture, which can result in discoloration and cracking of the product, as well as a reduction in the stiffness of the product and the bond between the fibers and the matrix, and a reduction in the thermal conductivity of the product. A higher refractive index is usually the result of a higher proportion of filler, which can result in voids in the carbon or glass fiber regions, which can cause the product to fail. In addition, a high refractive index is indicative of incomplete wetting of the fibers and poor bonding. Both of these conditions can affect the reaction during the curing process.

[0052] The impregnation tank is fitted with a number of extrusion bushings or doctor blades to remove excess resin. During the impregnation process, each tow can carry as much as three times the amount of resin that is needed in the final product. In order to achieve the proper ratio of fiber to resin in the cross section of the composite core, the fiber content is calculated. The extrusion bushings are designed to remove a predetermined amount of resin. For example, when the bushing has a passage that is twice the cross-sectional area of the fiber, a volume concentration of greater than 50% of the resin will not pass through the bushing and the excess resin will be removed. Alternatively, the bushing can be designed to allow 100% fiber and 20% resin to pass through.

[0053] The drawing referred to herein is accomplished by the drawing device 13 in combination with the winder 1. The drawing device draws the material from the creel 5 to the drawing device 13 and continuously pushes it into the final receiving winder 1. The winder 1 can have a storage capacity of 23,000 feet. The unimpregnated initial fiber tows 2 (carbon and glass fiber tows) extending from the exit end of the creel 5 serve as the lead heads at the beginning of the operation and are drawn through the winder from the spindles 3 through the tow guides 4. Specifically, the ends of the tows are drawn from the spindles and into the tow guides. The fibers are subjected to a tangential tension during the drawing process to prevent twisting of the fibers. Preferably, the fibers are drawn through the apparatus by one drawing device. Each creel contains a means for adjusting the tension of each spindle. For example, each creel can be provided with a small brake at the pay-off position for individually adjusting the tension of each spindle. The tension adjustment or guide mechanism minimizes the slippage and crossing of the fibers as they travel and aids in the wetting process. The tows are guided through the tow guides and then into the first oven.

[0054] Pre-heat the fibers: The carbon fiber tow and the glass fiber tow are pulled out of the impregnation tank 6 and into the first oven 7, where the carbon fiber tow and the glass fiber tow are pre-heated, compacted, and dehumidified.

[0055] The resin is heated to a specific temperature, which transforms the epoxy resin from a liquid state to a semi-cured state. The resin in the semi-cured stage is tacky, allowing the fiber tow to be bent, changed, compressed, and configured. This tackiness is controlled by adjusting the resin type, fiber type, yarn density, and fiber size, as well as the oven temperature. The first oven, which serves as a shaping device, compacts the fibers to a predetermined size, with dehumidification facilitated by a vacuum. The heating temperature in the first oven is 150°F to 250°F, to evaporate the moisture.

[0056] Shaping the fibers: The carbon fiber tow and the glass fiber tow are pulled out of the first oven 7 and into the second oven 8, where the carbon fiber tow and the glass fiber tow are compressed and shaped with the aid of a bushing. The second oven has multiple consecutive bushings for compressing and shaping the fiber tow, squeezing out the remaining epoxy resin, and adjusting the size of the fiber tow. The heating temperature in the second oven can be set to 150°F to 250°F. The semi-curing process is rapid, preferably lasting 1 to 1.5 minutes in a continuous production line, and is maintained constant throughout the process to facilitate the shaping, sizing, and further compaction of the product.

[0057] Preliminary curing of the fibers: The carbon fiber tow and the glass fiber tow are pulled out of the second oven 8 and into the progressive oven 9, where a number of optical fibers A are also pulled into the progressive oven 9, to preliminarily cure the carbon fiber tow, the glass fiber tow, and the optical fibers,

[0058] The progressive oven has multiple temperature zones, and the fiber tow passes through the progressive oven from upstream to downstream. The heating elements on both sides of the progressive oven heat the preformed fiber tow, causing the epoxy resin to cure, thereby transforming the core material properties from an initial state to a solid state.

[0059] Final curing of the fibers: The carbon fiber tow, the glass fiber tow, and the optical fibers are pulled out of the progressive oven 9 and into the post-curing oven 10, forming a core material that includes an inner core B of carbon fiber / epoxy resin, an outer core C of glass fiber / epoxy resin, the outer core surrounding the outer periphery of the inner core, and a number of optical fibers A located within the inner core B and / or the outer core C, as shown in Figure 2 and Figure 3 .

[0060] When the core material enters the oven for post-curing oven curing, the process allows for the temperature to be adjusted at any time as needed by the process according to a logic. For example, when the controller of the post-curing oven detects that the temperature is lower than the required temperature, the heating elements in the post-curing oven are activated; when the temperature is too high, the heating elements are turned off. The system achieves continuous closed-loop control through a series of temperature sensors and a PID system (feedback mechanism control system). Each heating unit is independent of and different from each other, and each heating element is separated by a specific logic and circuit. Preferably, after detecting the temperature difference, the controller activates a corresponding number of heating elements according to a specific thermal curve related to the process to provide sufficient heat. If the system needs to activate one of the seven heating elements according to the process requirements, the temperature sensor monitors the part that needs to be heated, and then the controller activates the corresponding heating elements in the heating assembly. In another embodiment, when all the thermocouples send a signal that heating is needed, the controller activates all the heaters in the heating assembly. In another case, the controller can activate a part of the heaters in the heating assembly, or turn off all the heating elements. It should be noted that the conduction heat can penetrate through the wall of the progressive oven to heat the fiber and epoxy resin to form a composite core. Alternatively, the heating elements can heat the fiber and epoxy resin in a pulsed manner.

[0061] The composite core cable manufacturing method has the following beneficial effects:

[0062] By using an aluminum conductor composite core reinforced cable, the current-carrying capacity can be improved. This reinforced composite core cable is a high-temperature-resistant, low-sag conductor that can operate at temperatures exceeding 100°C while maintaining stable tensile strength and creep elongation performance, and can achieve an actual use temperature limit of up to 230°C. The composite core cable can operate stably for about sixty years, and more preferably for seventy years, without the need to increase the outer diameter of the composite core or the conductor. Using the same diameter as the traditional ACSR cable, the composite reinforced cable can increase the line capacity by 50% at 180°C, without significantly affecting the structural load. In this way, without increasing the weight of the conductor, more aluminum material is provided for physical space, and the mechanical and physical performance can meet the requirements of sag limitation, thereby achieving more efficient and reliable power transmission.

[0063] The composite material formed by carbon fibers, glass fibers and epoxy resin is used to replace the original core material of the traditional power distribution and transmission conductor cable, and the composite material has a high elastic modulus and a low thermal expansion coefficient, thereby helping to improve the current-carrying capacity of the conductor cable.

[0064] The suitable refractive index of the epoxy resin, i.e. 1.50-1.58, ensures that the mixture can be directly used in each step of the production process without waiting for cooling or other processing steps, thus improving the process efficiency and ensuring the quality consistency of the final product. The realization of this feature is due to the precise control of the proportions and chemical composition of the components, which allows to stabilize the refractive index at the desired level, thus contributing to the production of defect-free products.

[0065] In some embodiments, the epoxy resin accounts for 15%-25% of the total weight of the composite core.

[0066] In some embodiments, the diameter of the core material is 5mm-10.5mm.

[0067] In some embodiments, the method for manufacturing the composite core cable further comprises the following steps:

[0068] The voids and damages of the core material are captured by the optical time domain reflectometer and the optical fiber A.

[0069] The optical fiber is very fragile and extremely sensitive to abnormalities of the cable, such as voids, cracks, dry spots, premature curing, etc. Any of the above abnormalities can damage the glass part of the optical fiber, resulting in the OTDR being unable to detect the transmission of the optical signal. Therefore, the introduction of the optical fiber into the manufacturing process for monitoring the composite core cable, by using the optical time domain reflectometer (OTDR) during the manufacturing process, verifies whether the composite core has been damaged due to impact, excessive bending or machine failure through the optical signal, which can detect problems caused by irregularities that may occur inside the composite core and capture voids or damages in the product, thus effectively guaranteeing the product quality and structural integrity.

[0070] Please refer to Figure 3 In some embodiments, there are two optical fibers A, one of which is arranged in the outer core C at the 6 o'clock and 12 o'clock positions, and the other is arranged in the inner core B. By reasonably arranging the spatial positions of the two optical fibers, the quality control level of the composite core cable during the manufacturing process and in actual application is significantly improved. It should be understood that the two optical fibers described in the above embodiments are only exemplary arrangements and are not a limitation of the present application. In actual application, the number, arrangement position and distribution mode of the optical fibers can be flexibly adjusted according to the specific structure of the composite core cable, the use scenario and the detection requirements.

[0071] The OTDR (optical time domain reflectometer) is used to ensure the normal function of the optical fiber and to detect any irregularities, voids or damages that may occur inside the composite core. This method not only improves the quality control level during the manufacturing process, but also detects the finished product at the final manufacturing stage (quality control) to ensure that the product has no internal defects before shipment. Compared with the traditional method, the present application provides a more advanced and effective monitoring means to ensure the overall performance and reliability of the cable.

[0072] In some embodiments, a universal progressive oven is employed that inserts a steel tube into the tube material, is suitable for a variety of different core material sizes, eliminates the expensive mold manufacturing and cleaning process, and results in significant process cost savings without the need to change the heating mold, but rather a steel tube is inserted into the progressive oven after each production run. After the steel tube is selected to correspond to the core material size, it is inserted into the heating mold for use during the manufacturing process. The cost of replacing the inserted steel tube after each production run is approximately only 0.4% of the actual mold cost, and is expected to have a significant impact on changeover labor costs, while enabling increased production line efficiency and cleaning processes.

[0073] In some embodiments, the optical fiber supply 6 contains 6 optical fiber bobbins. The bobbins are divided into three groups of two bobbins each, each group is clearly aligned with a respective supply line. Each bobbin is rotated on an independent spindle, equipped with a smooth running magnetic brake that can be individually adjusted for tension. The fiber bundles of each group do not contact or create sliding friction with each other before entering the final guide to the progressive oven. The optical fibers are guided by low inertia hard anodized aluminum guide wheels with a diameter of 70 mm, which travel a path that is first towards the front end of the progressive oven, and then vertically downward into the entrance of the progressive oven. The rotational status of each optical fiber bobbin is monitored by a broken line sensor. If a bobbin stops rotating due to a broken fiber or depleted material, the sensor will trigger a flashing alarm light on the optical fiber supply. The touch screen display will indicate the specific bobbin that triggered the alarm, and provide a reset button to reset the system after the material is replenished. The pulling device can smoothly pull the product through the entire process at a precisely controlled speed, ensuring that the product is not damaged.

[0074] In some embodiments, the pulling device 13 can employ a continuous pulling system driven by a vector drive electrical system / motor, rather than a traditional reciprocating system. The pulling system clamps and pulls the upper and lower portions of the product by means of the upper and lower conveyor belts, thereby performing the pulling function. Thus, the pulling system embodies a simplified and unified pulling system that is driven by a variable frequency drive (VFD) and operates at a precisely controlled speed.

[0075] Referring to Figure 1 In some embodiments, two creels 5 can be provided, each containing a plurality of bobbins containing fiber bundles. The bobbins can be interchangeable to adapt different types of fiber bundles according to the required properties and engineering specification table of the composite core material.

[0076] One particular advantage of the inventive concept is that low viscosity resins can be used in the process. The viscosity of the epoxy resin affects the speed of the forming process. In order to achieve the fiber / resin ratio required to form the composite core, the viscosity of the epoxy resin is in the range of 200 to 1500 cP (centipoise). Preferably, the viscosity of the epoxy resin is in the range of 200 to 600 centipoise. The epoxy resin selected should have good mechanical properties and be able to withstand long term operating temperatures of up to about 230°C for a period of at least 60 years, more preferably, for a period of at least 70 years.

[0077] According to the present invention, a fiber / resin ratio of 62% to 75% by weight is achieved. Preferably, the fiber / resin ratio is between 72% and 75% by weight. The low viscosity resin allows for sufficient wet out of the fibers and is suitable for the manufacture of the composite core. A preferred polymer has a wide range of chemical resistance, and has very stable dielectric and insulating properties. Further preferably, the polymer meets the outgassing requirements of ASTM E 84 and the UL 94 flame retardant test standards, and can be operated at intermittent high temperatures of 220°C to 280°C without causing thermal or mechanical damage to the reinforcing material.

[0078] In order to achieve the desired fiber to epoxy resin ratio, a plurality of deflection wiper bars are provided on the upstream side of the impregnation tank. As the fibers are drawn through the impregnation tank, the fibers are moved up and down and past a series of wiper bars to remove excess resin. Alternatively, excess resin can be removed from the fibers as they exit the tank by a wiper system. Preferably, the excess resin is collected and recycled back into the impregnation tank. A recovery tray is provided below the impregnation tank to collect excess epoxy resin as needed. Preferably, the impregnation tank has an auxiliary tank with an overflow function. Excess epoxy resin is returned to the auxiliary tank by gravity through a pipe. Alternatively, excess resin is collected through an overflow channel and returned to the impregnation tank by gravity. In another alternative, a drain pump system can be used to circulate resin from the auxiliary tank back to the impregnation tank. Preferably, the resin level in the tank is controlled by a computer system. When a low level is detected by a level sensor, a pump is activated to pump resin from the auxiliary mixing tank to the impregnation tank.

[0079] A limiting guide is provided within the impregnation tank 6 to reorient the fibers during the impregnation process. The guide is preferably located in the middle of the impregnation tank and causes the fibers to move up and down perpendicular to the direction of the draw. This deflection causes the fibers to reconfigure from a circular arrangement to a flat arrangement. The flat arrangement allows the fibers to spread side by side, allowing the epoxy resin to more fully wet out the fibers.

[0080] In some embodiments, the resin is mixed with the three component epoxy resin in the mixing tank according to the specifications and then pumped through a pump to the resin feeders in the impregnation tank. The resin feeders are equipped with visual level devices and control valves to ensure proper flow of the epoxy resin to the impregnation tank.

[0081] Referring now to the drawings Figure 1 In some embodiments, the composite core cable manufacturing method further comprises the steps of:

[0082] purification: after the core material exits the curing oven 10, it enters the contaminant extraction system 11 to remove volatile organic compounds that can be generated during the high temperature curing process, improving the cleanliness and appearance of the finished cable product;

[0083] After the core material exits the contaminant extraction system 11, it enters the cooling system 12, where it is allowed to cool to room temperature. This process promotes increased cross-linking within the resin matrix, thereby improving the physical properties of the composite core material. The process typically leaves a gap between the heating and cooling processes and the pulling device, allowing the product to cool naturally or by convection, ensuring that the pulling device used to hold and pull the product does not damage it.

[0084] In some embodiments, the cooling system 12 includes a variable speed blower. The blower is located upstream of the cooling device and continuously blows air into the cooling chamber in an upstream direction. The air is circulated in a closed loop direction within the device, keeping the entire air at a constant temperature. In another alternative, the cooling system includes a spiral cooler. The preferred cooling temperature range is about 40 to 110 degrees Fahrenheit.

[0085] Preferably, the composite core material is cooled before the pulling device grips the compacted composite core material. The composite core material is cooled by air convection over a distance of about 8 to about 15 feet before it reaches the pulling device. Most preferably, the cooling distance is about 10 feet.

[0086] For the strength of the core material, it is critical that no excessive stress is placed on the core material due to bending during the winding process. In one embodiment, the core material is not twisted and can only be bent to a certain degree. In another embodiment, the wheel is seven feet in diameter and can accommodate up to 23,000 feet of fully cured composite core material. The wheel is designed to take into account the rigidity of the formed composite core material and does not force the core material into a tight bend. In a further embodiment, the winding device includes a device that prevents the wheel from reversing from winding to unwinding, which can be any device that prevents the wheel from reversing, such as a braking system.

[0087] In some embodiments, the composite core cable manufacturing method includes a quality control system consisting of an inline inspection system to ensure product consistency. The quality control system can include: laser marking of the composite core material; recording the number of fiber strands in the final product; monitoring the quality of the resin; monitoring the temperature of the ovens and the product at various stages; monitoring the functionality of the optical fiber; measuring the molding conditions; measuring the speed of the pulling process. For example, each batch of composite core material has corresponding data to maintain the optimal operation of the process. Alternatively, the quality control system includes a marking system that marks the product information of a specific batch on the composite core material.

[0088] Referring to Figure 2 and Figure 3 In some embodiments, the composite core cable manufacturing method further includes the following steps:

[0089] Winding an aluminum segment around the core material to form a first aluminum conductor D around the outer periphery of the outer core C and a second aluminum conductor E around the outer periphery of the first aluminum conductor D.

[0090] Winding multiple aluminum segments around the composite core material in a counterclockwise or clockwise direction to optimize the amount of aluminum used and improve electrical conductivity. The cross-section of the aluminum segment is trapezoidal, and the trapezoidal geometry allows each segment to fit closely together and tightly against the corresponding inner layer. The multiple aluminum segments of the first aluminum conductor are wound around the outer periphery of the outer core in a counterclockwise direction, tightly fitting the composite core surface; subsequently, the multiple aluminum segments of the second aluminum conductor are wound around the outer periphery of the first aluminum conductor in a clockwise direction, thereby forming a composite structure consisting of a composite core and a double-layer aluminum conductor. This structure not only retains the advantages of lightweight and high strength of the composite core, but also improves the overall electrical conductivity and mechanical support performance of the cable through the aluminum conductor.

[0091] In some embodiments, the composite core cable has an operating temperature of 230°C or less, a tensile strength of 150-240 ksi, an elastic modulus of 7 Msi-30 Msi, and a thermal expansion coefficient of 0-6*10-6 m / m / C. To achieve these physical properties, the composite core of the present application can use a reinforcing fiber with inherent physical properties to meet the required physical specifications of the composite core. From a practical application perspective, most cables within the scope of the present application contain at least two different types of reinforcing fibers. Combining two or more types of reinforcing fibers in the composite core material significantly improves the strength-to-weight ratio compared to materials commonly used in power transmission system cables.

[0092] The composite core of the present application preferably includes fiber strands having a relatively small yield or K number. Fiber strands are untwisted bundles of continuous microfibers whose composition is expressed by yield or K number. For example, a 12k fiber strand contains 12,000 individual microfibers. Ideally, the microfibers are sufficiently infiltrated by the resin such that the resin coats the circumference of each microfiber within the fiber strand. The infiltration effect can be influenced by the size of the fiber strand, i.e., the number of microfibers in the strand and the size of the individual microfibers. Larger fiber strands, due to the greater number of fibers contained therein, result in a more difficult resin to fully infiltrate each fiber; while smaller fiber diameters facilitate more even distribution of the resin around each fiber. Infiltration and penetration of the fiber strands in the composite material is critical to the performance of the final composite material. Inadequate infiltration can result in defects or dry spots in the composite material, thereby reducing the strength and durability of the composite material. The fiber strands can also be selected based on the size of the fiber strands that the process can handle to form a composite material having the desired physical properties. In this embodiment, both glass and carbon fibers are selected, with carbon fiber strands preferably selected having a K number ranging from 4k to 50k, and glass fiber strands preferably selected having a yield ranging from 800 to 1200. More specifically, the individual reinforcing fibers are preferably sized as follows: glass fibers having a diameter ranging from 8 to 15 microns, preferably 10 microns. Carbon fibers having a diameter ranging from 5 to 10 microns, preferably 7 microns. For other types of fibers, the appropriate size range can be determined based on the desired physical properties. These size ranges are selected based on optimal resin infiltration and process feasibility. For example, fibers having a diameter less than about 5 microns can pose a health risk to the operator due to their small size; while fibers approaching 25 microns can be difficult to process due to increased rigidity and brittleness.

[0093] The fiber strands used in the composite core are substantially continuous in length. In practice, the carbon fiber strands used in the present application are desirably between 1000 and 3000 microns in length, depending on the size of the spool. More broadly, the length of the selected fibers can range from 1000 to 33,000 microns. The longest fibers that can be accommodated by the processing equipment are preferably selected to reduce the number of splices, thereby forming a continuous composite core in excess of 6000 feet. The fiber ends can be joined end-to-end by gluing to form a substantially continuous longer fiber strand. Continuous pulling causes the fibers to align in the longitudinal direction of the cable.

[0094] The composite core contains reinforcing fibers that have significant heat resistance, which allows the composite cable to transmit higher power because the composite core can withstand higher operating temperatures. The fibers used in the present invention can withstand operating temperatures in the range of about 90 to 230°C. More preferably, the fibers can withstand operating temperatures in the range of about 170 to 200°C. In addition, the fibers used in the present invention can also withstand ambient temperatures in the range of about -40 to about 90°C. That is, the composite core can maintain its physical properties unimpaired at temperatures as low as -40°C under ambient conditions where no current is flowing through the composite cable.

[0095] The fibers can be selected from a group of fibers, each fiber type having different subtypes with different properties that can be combined in various combinations to achieve a particular composite effect. The present invention is not limited to a particular type of fiber, and other types of fibers can be used as long as the physical properties required by the present invention are met.

[0096] The relative amounts of each reinforcing fiber type can be adjusted depending on the physical properties required for the composite cable. For example, fibers with lower modulus of elasticity help to form a composite core that is high in strength and rigid. Carbon fiber strands have a tensile strength of 350 Ksi to 750 Ksi and a modulus of elasticity of 22 Msi to 37 Msi, while glass fibers are low modulus reinforcing fibers with a modulus of elasticity in the range of 6 Msi to 7 Msi and a tensile strength of 180 Ksi to 220 Ksi. These two types of fibers can be combined to take advantage of their inherent physical properties to produce a composite core that is high in strength, rigid, and flexible. By combining glass fibers with lower tensile strength with carbon fibers with higher tensile strength, the overall tensile properties of the composite material can be improved. For example, the tensile strength of the carbon fibers can be selected to be 350 Ksi, 400 Ksi, 600 Ksi, or 750 Ksi, and the modulus of elasticity can be selected to be 22 Msi, 30 Msi, or 37 Msi, while the modulus of elasticity of the glass fibers can be selected to be 6 Msi, 6.5 Msi, or 7 Msi, and the tensile strength can be selected to be 180 Ksi, 200 Ksi, 210 Ksi, or 220 Ksi. The combination of the properties of these two types of fibers results in a new type of cable with more desirable physical properties. The strain capability of the composite material is closely related to the inherent physical properties of the components and their volume fractions. Once the fiber / resin composite system is selected, the strain-to-failure ratio of each fiber / resin composite is determined. According to the present invention, the resin can be custom designed to meet the process requirements and the physical property requirements of the final product. Thus, the strain-to-failure ratio of the combination of the fibers and the custom resin is also determined. For example, the strain-to-failure ratio of carbon fiber / epoxy resin is 1.7%. Accordingly, the composite core is designed with carbon fiber / epoxy resin in the inner core, which has higher rigidity, and glass fiber / epoxy resin in the outer layer, which is more flexible, to form a composite core with the desired flexibility and low coefficient of thermal expansion.

[0097] The composite core includes an inner carbon fiber / resin core having a cross-sectional area of 0.037 square inches and a fiber to resin weight ratio of approximately 70 / 30, and an outer glass fiber / epoxy resin layer having a cross-sectional area of 0.074 square inches and a fiber to resin weight ratio of approximately 75 / 25. The fibers are embedded in a resin matrix, and the volume ratio of fiber to resin is at least 50:50%. The volume fraction refers to the ratio of the cross-sectional area of the fiber to the total cross-sectional area, and the weight of the fiber will determine the final percentage by weight.

[0098] According to the present application, the volume fraction of the fiber in the fiber / resin composite is preferably between about 50% and 57%. Most importantly, the composite core is designed to have an inner reinforced core body that is comprised of an advanced composite material, and an outer layer of more flexible material surrounding the inner core body. By advanced composite material, it is meant a composite material that contains continuous fibers in a volume fraction that exceeds 50% and that has mechanical properties that are superior to those of glass fibers. Glass fibers are mechanically suitable for splicing, whereas advanced composite materials are more brittle and are not suitable for splicing. The fibers that form the outer low modulus layer surrounding the advanced composite material preferably have the following properties: a tensile strength in the range of about 6 Msi to 7 Msi; a coefficient of thermal expansion in the range of 5 x 10 -6 to 10 x 10 -6 m / m / °C; an elongation at break in the range of 3% to 6%; a dielectric property in the range of 0.034 to 0.04 W / m-K; and a density in the range of 0.065 to 0.013 lb / in 3 .

[0099] The physical properties of the composite core can be adjusted by adjusting the fiber / resin ratio in each component. Alternatively, the physical properties can be adjusted by adjusting the area percentage of each component in the composite core material. For example, by reducing the total area of the carbon fiber portion (from 0.037 square inches) and increasing the area of the glass fiber portion (from 0.074 square inches), the resulting composite core material has a reduced stiffness in the carbon core portion and an increased flexibility overall. In addition, because the diameter of the glass fiber bundle is smaller than the diameter of the carbon fiber bundle, the resulting composite core has a smaller diameter, thereby allowing more conductor material to be housed in the overall cable size.

[0100] In some embodiments, a third fiber (e.g., basalt fiber) can be introduced into the composite core. This additional fiber can change the physical properties of the final product. For example, replacing some of the carbon fiber with basalt fiber can increase the dielectric properties of the composite core while decreasing the stiffness of the core. Basalt fiber has the following properties: high tensile strength of about 701.98 Ksi (in comparison, glass fiber ranges from about 180 to 50 Ksi); high elastic modulus of about 12.95 Msi; and low coefficient of thermal expansion of about 8.0 ppm / °C (in comparison, glass fiber ranges from about 3% to 6%). Basalt fiber provides higher tensile strength, an elastic modulus between that of carbon fiber and glass fiber, and an elongation close to that of carbon fiber. Another advantage is that basalt fiber has better dielectric properties than carbon fiber. Preferably, the composite core includes an inner non-conductive, stiff core. By designing an advanced composite core with fibers having inherent physical properties and coating it with a low modulus fiber outer layer, a new set of composite core properties is achieved. It is noted that other fibers that can be used include, but are not limited to, aramid fiber, liquid crystal fiber, Kevlar fiber, boron fiber, high performance polyethylene fiber, and carbon nanofiber (CNF).

[0101] In some embodiments, a key element of the present invention is the ability to splice the composite core in the final cable product. The resin used in the composite core of the present invention has a neat resin fracture toughness preferably in the range of about 0.87 INS-1b / in to about 1.24 INS-1b / in. The composite core of the present invention includes a resin having a low coefficient of thermal expansion. The low coefficient of thermal expansion reduces the sag of the resulting cable. The resin of the present invention preferably operates in the range of about 15 x 10 -6 / °C to about 42 x 10 -6 / °C. The resin used in the composite core of the present invention has an elongation greater than about 4.5%.

[0102] In some embodiments, the composite core of the present invention includes fibers embedded in an epoxy resin, and the fiber volume fraction is at least 50%. The ratio of fiber to resin affects the physical properties of the composite core material. In particular, the strength, electrical conductivity, and coefficient of thermal expansion are all dependent on the fiber volume content of the composite core. Generally, the higher the volume fraction of fiber in a composite material, the higher the tensile strength of the resulting composite material. The volume ratio of fiber to resin in the present invention is preferably between about 50% and 57%, and the corresponding weight percentage is preferably between about 62% and about 75%. More preferably, the fiber / resin ratio in the present invention is between about 65% and about 72% by weight. Most preferably, the fiber volume fraction in the present invention is at or above about 72% by weight.

[0103] In some embodiments, each fiber type in the composite core can have a different fiber / resin weight ratio relative to the other fibers. This is achieved by selecting an appropriate number of each type of fiber and an appropriate resin type. For example, a composite core material comprising a carbon fiber / epoxy inner core and an outer layer of glass fiber / epoxy can be composed of 126 glass fiber spools and an epoxy resin having a viscosity of 2000 to 6000 cPs at 50°C to achieve a predetermined fiber / resin ratio of about 75 / 25 by weight. Preferably, the resin can be adjusted to achieve the viscosity required for the process. The composite can also comprise about 16 carbon fiber spools and an epoxy resin having a viscosity of 2000 to 6000 cPs at 50°C to achieve a predetermined fiber / resin ratio of about 70 / 30 by weight. By varying the number of fiber spools, the weight ratio of fiber to resin can be adjusted, thereby varying the physical properties of the composite core material product. Alternatively, the fiber / resin ratio can also be varied by adjusting the viscosity of the resin, either increasing or decreasing it. The composite cable manufactured according to the inventive concept exhibits tunable physical properties, which specific physical properties can be controlled by varying parameters during the composite core forming process. More specifically, the composite core forming process is tunable to achieve the desired physical properties in the final cable.

[0104] One advantage of the composite core cable manufacturing method is that the components of the composite material can be adjusted to achieve the desired goal of the composite core, which is a cable that does not increase in sag due to excessive thermal expansion when energized, while not decreasing the tensile strength. Preferably, different types of fibers are used in combination to integrate the physical properties of each. By forming a core body with higher strength and stiffness combined with an outer layer that is more flexible, the overall performance can be enhanced. The process enhances the optimal properties of the composite material by preventing roving twist, thereby achieving more uniform wet-out and superior strength properties.

[0105] In a preferred embodiment of the composite core material, the composite core comprises glass fibers and carbon fibers, with 126 glass fiber spools and 16 carbon fiber spools mounted on the creel, and the fiber bundles drawn from the spools pass through the fiber bundle guides. The fiber bundle channels are arranged in such a way that the resulting composite core material has a uniform carbon fiber inner core and a glass fiber outer layer. The carbon fiber layer has high strength and high stiffness, and is a weak electrical conductor. The outer layer of low modulus glass fiber is more flexible and is not an electrical conductor. The glass fiber outer layer provides an external insulation layer between the carbon fiber and the high electrical conductivity aluminum cladding in the final composite conductor product.

[0106] Referring to Figure 4The fiber bundle guide 4 comprises a ceramic and steel ferrule with multiple channels arranged in a predetermined pattern to guide the fibers to prevent fiber crossing. The fiber bundle guide contains a ferrule with sufficient spacing to insert the fibers in a predetermined pattern. The channels are arranged in rows with varying numbers of rows, with larger diameter carbon fibers passing through the center two rows of channels 15 and smaller diameter glass fibers passing through the two outer rows of channels 16. A tensioning device is preferably provided on each spool to adjust the tension of the pulled fibers and to ensure that the fibers are pulled straight through the guide.

[0107] 36 carbon fibers pass through a fiber bundle guide comprising 3 rows of 36 channels, 3 rows on the inside and 3 rows on the outside, in a 3 layer configuration. In addition, 4 rows of 12 glass fiber spools also pass through similar channels after passing through the fiber bundle guide.

[0108] Further, at least two fibers are pulled through each channel of the fiber bundle guide. For example, a fiber bundle guide comprising 26 channels can pull 52 fibers through, with two fibers per channel. If one of the pair of fibers breaks, the sensing system will alert that there is a fiber break. Depending on the location of the break, the repair can be made without stopping the process. The repair method is to pull a new fiber from the creel and splice it to the new end of the broken fiber. The fibers are arranged in parallel in specific rows.

[0109] Figure 6 The carbon fiber path is shown, with 36 carbon fibers passing through a fiber bundle guide comprising 3 rows of 36 channels, 3 rows on the inside and 3 rows on the outside, in a 3 layer configuration. In addition, 4 rows of 12 glass fiber spools also pass through similar channels after passing through the fiber bundle guide.

[0110] Figure 7A cross section of the round bushing 17 is shown, which can accommodate cables of different sizes from 6 mm to 11 mm. The bushing 17 includes a cylindrical portion 18 and a central hole through which the pulling mechanism pulls the fiber bundle. The cylindrical portion 18 interlocks with the long steel beams on the outside to support the bushing 27. The size of the passageway in each bushing varies and is also changed in each subsequent bushing in the upstream direction. Preferably, the round bushings are specially designed for sizes from 6 mm to 11 mm depending on the cable diameter and process requirements. These bushings serve to reduce the amount of epoxy resin used and act as a sizing device before the fiber bundle enters the post-cure oven. An amount of heat is added or removed by the heating and cooling process to achieve the temperature changes required for the curing of the carbon and glass fiber epoxy resin matrix. The bushings are mounted on the hook-like portions of the interlocking support structure and are spaced apart from each other. The function of the bushings is to continuously compress the carbon fibers and form a composite core composed of carbon fibers, during which the carbon fibers are under proper tension to achieve the concentricity and uniform distribution of the fibers without mixing between the fibers.

[0111] The temperature is monitored throughout the compression bushings 20 and the progressive oven by a programmable logic controller (PLC) and a PID system. The temperature is determined by the process and is high enough to keep the resin in a semi-cured state. At the end of the bushings, the product passes into the oven for curing and final shaping to achieve the final degree of compaction and the final diameter.

[0112] In some embodiments, the progressive oven employs a pre-set heating profile by a programmable logic controller to cure the carbon / glass fiber bundle and shape the product to the final desired shape. According to the inventive concept, the preferred curing temperature range is from about 350 degrees Fahrenheit to about 400 degrees Fahrenheit. The curing process is preferably performed over a length of about 8 to about 15 feet. More preferably, the length of the curing process is about 8 feet. The high temperature of the progressive oven and the post-cure oven causes the resin to finally cure and form a hard resin structure.

[0113] Figure 5 A schematic view of the oven is shown.

[0114] In this embodiment, the specific specifications of the glass fiber used are as follows:

[0115] Model: Vetrotex Leno R099-686 (yield 900); tensile strength: 298103 PSI; elongation at break: 3.0%; tensile modulus: 11.2 x 106 PSI; glass content: 57.2%.

[0116] The specific specifications of the carbon fiber used are as follows:

[0117] Torayca T700S (24K yield); tensile strength: 711 Ksi; tensile modulus: 33.4 Msi; strain (elongation at break): 2.1%; density: 0.065 lb / ft3; filament diameter: 2.8 x 10"4inches.

[0118] The specific specifications of the epoxy resin used are as follows:

[0119] Torayca T700S (24K yield); tensile strength: 711 Ksi; tensile modulus: 33.4 Msi; strain (elongation at break): 2.1%; density: 0.065 lb / ft3; filament diameter: 2.8 x 10"4inches.

[0120] The specific specifications of the curing agent used are as follows:

[0121] Torayca T700S (24K yield); tensile strength: 711 Ksi; tensile modulus: 33.4 Msi; strain (elongation at break): 2.1%; density: 0.065 lb / ft3; filament diameter: 2.8 x 10"4inches.

[0122] The specific specifications of the filler used are as follows:

[0123] Torayca T700S (24K yield); tensile strength: 711 Ksi; tensile modulus: 33.4 Msi; strain (elongation at break): 2.1%; density: 0.065 lb / ft3; filament diameter: 2.8 x 10"4inches.

[0124] The specific specifications of the modifier used are as follows:

[0125] Torayca T700S (24K yield); tensile strength: 711 Ksi; tensile modulus: 33.4 Msi; strain (elongation at break): 2.1%; density: 0.065 lb / ft3; filament diameter: 2.8 x 10"4inches.

[0126] Mixed solution:

[0127] A 1000 gram epoxy resin system was mixed, where the resin was 421 grams, the curing agent was 525 grams, the filler was 42 grams, and the modifier was 29 grams. The volume fraction of the epoxy resin in the composite core is typically 10-20%, depending on the number of glass filaments, the number of carbon filaments, the tooling design, and the distribution of the fibers and the epoxy resin. When mixing, 421 grams of resin were mixed with 42 grams of filler to make a premix, 525 parts of the curing agent and 29 parts of the modifier were added, and finally a mixture with the target refractive index was formed. The refractive index of the epoxy resin was measured after all the components were mixed and was 1.58.

[0128] It is important to note that deviations in the proportion of components (100:125:10:7) can affect the refractive index, resulting in a glass transition temperature (Tg) below 180°C, thus reducing the expected load capacity, as the mandrel cannot reliably withstand the weight of the conductor, ultimately leading to unexpected sagging of the power line.

[0129] When mixing the solution, the refractive index result is higher than 1.58 due to the resin content being higher than 100 parts, in which case we cannot separate the components. Corrective action: increase the proportion of fillers to reduce the refractive index until it is within the tolerance range.

[0130] When mixing the solution, the refractive index result is lower than 1.58 due to the resin proportion being lower than 100 parts, corrective action: add resin to the mixture until the refractive index reaches the target range of 1.50-1.58.

[0131] Mandrel size:

[0132] The invention includes 9 different core sizes, ranging from 5mm to 10.5mm, to meet the needs of different customers and load capacities, capable of withstanding different conductor loads for optimal efficiency. Each mandrel size has a different tooling to ensure proper distribution of epoxy resin, carbon fiber, and glass fiber.

[0133] The number of glass fiber filaments and carbon fiber filaments varies for different mandrel sizes.

[0134] Example: A 7mm core consists of 32 carbon fiber bobbins or 32 carbon fiber strands (each containing 12000-24000 carbon fiber filaments) and 28 glass fiber bobbins or 28 glass fiber strands (each containing 2000-4800 glass fiber filaments). The number of carbon fiber and glass fiber bobbins represents the core diameter, and this number also varies for different core diameters. Each mandrel size is equipped with a special tooling for controlling epoxy resin distribution and determining the maximum load capacity (load capacity).

[0135] The larger the composite core diameter, the higher its tensile load capacity, but the effective tensile strength per unit area also depends on the special fiber arrangement and material properties in the invention. As the core diameter increases, the material can absorb more epoxy resin, but through the special tooling designed by us to control the content of epoxy resin, it is kept within the range of 10-20% by volume, and it will not exceed this range. As the core diameter increases, the tensile strength of the core also increases, and the elastic modulus of all core sizes remains the same, as this is an inherent property of the material itself.

[0136] Parameters pre-selected according to the required Ampacity are as follows: core rod diameter, number of carbon fiber bobbins, number of glass fiber bobbins, special tooling for epoxy distribution, oven process tooling for selected core rod diameter, pre-sized heating sleeve, conductor diameter.

[0137] The greater the composite core diameter, the greater the tensile load capacity it can withstand, but the effective tensile strength per unit area also depends on the special fiber arrangement in this invention (related to tooling design) and the performance of the material itself.

[0138] With the increase of the composite core diameter, the material can absorb more epoxy resin, but through the special tooling we designed, the content of epoxy resin is controlled within the range of 10% to 20% by volume, and it will not exceed this range.

[0139] With the increase of the core material diameter, the tensile strength of the core material also increases, but due to the performance limitations of the material itself and the tooling design limitations related to the distribution of carbon fiber and glass fiber, this improvement is limited.

[0140] We use 237 parts as a constant reference value in each formulation to define the mixing ratio between components, regardless of the specific volume of epoxy resin in the final composite material.

[0141] The greater the composite core diameter, the greater the tensile load capacity it can withstand, but the effective tensile strength per unit area also depends on the special fiber arrangement in this invention (related to tooling design) and the performance of the material itself.

[0142] With the increase of the composite core diameter, the material can absorb more epoxy resin, but through the special tooling we designed, the content of epoxy resin is controlled within the range of 10% to 20% by volume, and it will not exceed this range.

[0143] With the increase of the core material diameter, the tensile strength of the core material also increases, but due to the performance limitations of the material itself and the tooling design limitations related to the distribution of carbon fiber and glass fiber, this improvement is limited.

[0144] Composite core cable Ampacity examples, with a refractive index of 1.50 to 1.58:

[0145] Core diameter Conductor diameter Core strength Conductor strength Current carrying capacity 7 mm 18.2 mm 86 / Kn 98 / Kn 1009@180C 8 mm 25 mm 112 / KN 135 / Kn 1620@180C 9.5 mm 32 mm 153 / Kn 185 / Kn 1880@180C 10.5 mm 39 mm 188 / Kn 246 / Kn 2900@180C

[0146] Experimental Note: When the refractive index is outside the tolerance range, the deviation of the refractive index indicates that the resin is not fully or properly cured, or the ratio of resin, filler and curing agent is incorrect. This can result in a decrease in the bonding strength between the carbon fiber and the matrix, reducing the mechanical strength by up to 50%. The present invention relies on the good adhesion between the resin and the carbon fiber, glass fiber to achieve effective load transfer. Therefore, the specific refractive index is selected to meet these key performance requirements.

[0147] If the refractive index of the matrix is not within the range of 1.50-1.58, the resin will not be properly bonded, resulting in a significant decrease in the tensile strength and structural integrity of the core material. At the same time, the incorrect refractive index also indicates that the material has poor thermal performance, with a reduced glass transition temperature (Tg), making the core material more prone to deformation or failure at high temperatures. In addition, the non-compliance of the refractive index also creates micro voids in the core structure, affecting its electrical insulation performance. These voids can also become crack initiation points or delamination points, further affecting the mechanical stability of the core material.

[0148] For the composite core material described in the present invention, when its refractive index is within the range of 1.50-1.58, its glass transition temperature (Tg) measured by dynamic mechanical analyzer (DMA) is 180-210℃, which is sufficient to meet the thermal and mechanical performance requirements required for design Ampacity.

[0149] Viscosity (Viscosity):

[0150] The viscosity of the epoxy resin mixture used in the manufacturing process of the present invention is in the range of 500-1500 centipoise (cP), measured at room temperature. This viscosity range ensures that the epoxy resin has good wet out on the carbon fiber and glass fiber, and achieves full impregnation. In the present invention, we maintain the controllable flowability of the epoxy resin by the following ways: Resin formulation: selection of resin type, curing agent, filler and modifier; Resin tank design: by reasonably designing the resin tank structure and keeping its temperature stable, it helps to control the resin viscosity during the manufacturing process; Proportion control: using the above mixed formula, ensure the proportion of each component constant, so as to maintain the acceptable refractive index.

[0151] High viscosity resin: will result in poor resin flowability, dry spots inside the core material, and reduce the glass transition temperature (Tg);

[0152] Low viscosity resin: if the resin content is too high, it will result in too much resin wrapping around the carbon fiber and glass fiber in the core material, which will reduce the mechanical performance, and affect the Ampacity due to sagging and reduced glass transition temperature.

[0153] Elastic Modulus:

[0154] Core size, Carbon fiber type, Carbon fiber volume, Manufacturing process, Fiber distribution, Tool design, Fiber orientation. Compared with the ACSS (Aluminum Conductor Stress Control System) in the prior art, the elastic modulus of the present application is reduced by 40% to 44%, thereby realizing the following significant advantages:

[0155] Lower thermal sag under high temperature conditions; weight is reduced by 70%; material aging and performance degradation are less.

[0156] Coefficient of Thermal Expansion (CTE):

[0157] The coefficient of thermal expansion of the present application is a key advantage compared with conventional reinforced conductors and the prior art, which is mainly due to the selected carbon fiber and its orientation design. The coefficient of thermal expansion (CTE) in the present application is significantly reduced, thereby bringing the following advantages:

[0158] Minimal sag, stable mechanical properties, better current-carrying capacity.

[0159] Thermal Mechanical Analysis (TMA) can be used to measure the dimensional change of the sample for evaluating its thermal expansion behavior. The coefficient of thermal expansion of the composite core is determined by a thermal mechanical dilatometer, thereby determining the expansion characteristics of the material when the temperature rises.

[0160] Please refer to Figure 2 and Figure 3 The present embodiment also provides a composite core cable made by the composite core cable manufacturing method described in any one of the above embodiments.

[0161] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of the present application, they do not limit the patent protection scope of the present application. Any equivalent structure or equivalent process substitution or modification based on the essential concept of the present application, using the content described in the specification and drawings, and directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, etc., are all included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a composite core cable, characterized in that, Includes the following steps: The traction carbon fiber bundle and glass fiber bundle pass through the fiber bundle guide into the impregnation tank for full impregnation. The impregnation tank contains a mixed solution consisting of 100 parts epoxy resin, 125 parts curing agent, 7 parts modifier and 10 parts filler. The refractive index of the mixed solution is 1.50 to 1.

58. The carbon fiber bundles and glass fiber bundles are pulled out of the impregnation tank and into the first drying oven to preheat, compact and remove moisture from the carbon fiber bundles and glass fiber bundles; The carbon fiber bundle and glass fiber bundle are pulled out of the first drying oven and into the second drying oven, where they are compressed and shaped with the help of the bushing. The carbon fiber bundles and glass fiber bundles are pulled out of the second oven and into the progressive oven. Several optical fibers are also pulled into the progressive oven to perform preliminary curing of the carbon fiber bundles, glass fiber bundles and optical fibers. The carbon fiber bundle, glass fiber bundle, and optical fiber are pulled out of the progressive oven and enter the post-curing oven to form a core material. The core material includes an inner core, an outer core, and several optical fibers. The inner core is made of carbon fiber / epoxy resin, and the outer core is made of glass fiber / epoxy resin. The outer core surrounds the outer periphery of the inner core, and the optical fibers are located inside the inner core and / or the outer core.

2. The method for manufacturing composite core cables according to claim 1, characterized in that, It also includes the following steps: The voids and damage in the core material are captured using an optical time-domain reflectometer and optical fiber.

3. The method for manufacturing a composite core cable according to claim 1 or 2, characterized in that, There are two optical fibers. One fiber is located inside the outer core and positioned at the 6 o'clock and 12 o'clock positions, while the other fiber is located inside the inner core.

4. The method for manufacturing composite core cables according to claim 1, characterized in that, It also includes the following steps: After the core material leaves the curing oven, it enters the contaminant extraction system. The core material is pulled away from the contaminant extraction system and enters the cooling system, where it waits for the core material temperature to drop to room temperature.

5. The method for manufacturing a composite core cable according to claim 1, characterized in that, It also includes the following steps: An aluminum segment is wound around the core material to form a first aluminum conductor and a second aluminum conductor. The first aluminum conductor surrounds the outer periphery of the outer core, and the second aluminum conductor surrounds the outer periphery of the first aluminum conductor.

6. The method for manufacturing a composite core cable according to claim 1, characterized in that, The viscosity of epoxy resin is 200 cP to 1500 cP. The tensile strength of carbon fibers in carbon fiber bundles is 350Ksi to 750Ksi, and the elastic modulus is 22Msi to 37Msi. The tensile strength of glass fibers in glass fiber bundles is 180Ksi to 220Ksi, and the elastic modulus is 6Msi to 7Msi.

7. The method for manufacturing a composite core cable according to claim 1, characterized in that, The diameter of a single carbon fiber is 5µm to 10µm, and the diameter of a single glass fiber is 8µm to 15µm.

8. The method for manufacturing a composite core cable according to claim 1, characterized in that, The heating temperature in the first and second ovens is 150℉~250℉; The heating temperature in the progressive oven is 330℉~370℉; The heating temperature in the post-curing oven is 400℉.

9. The method for manufacturing a composite core cable according to claim 1, characterized in that, The diameter of the core material is 5mm to 10.5mm.

10. A composite core cable, characterized in that, It is prepared by the method of manufacturing composite core cable according to any one of claims 1 to 9.

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