A method for manufacturing a flywheel energy storage cable and the cable itself.

Abstract

This invention belongs to the field of cable manufacturing technology and provides a method for manufacturing a flywheel energy storage cable and the cable itself. By acquiring a three-dimensional digital model of the cable and combining it with high-voltage electric field simulation analysis, the stress and electric field distribution of the cable under high-voltage conditions can be accurately assessed. This effectively identifies weak areas in the cable that are prone to damage and current breakdown. For these high-risk areas, structural optimization and electrical correction are performed to improve the mechanical strength and electrical insulation performance of the cable, thereby controlling the failure probability of the cable. The invention also monitors electrical treeing caused by structural damage in real time and accurately identifies and locates defect areas, thus significantly improving the sensitivity and accuracy of defect detection and ensuring the long-term stability and safety of the cable in high-voltage working environments.

Description

Technical Field

[0001] This invention belongs to the field of cable manufacturing technology, specifically relating to a method for manufacturing a flywheel energy storage cable and the cable itself. Background Technology

[0002] Cross-linked polyethylene (XLPE) insulated power cables are a common type of cable used for transmitting electricity. XLPE is a polymer material that, through a special cross-linking process, forms a three-dimensional network structure between its molecular chains, improving its resistance to electrical breakdown and thermal performance. In XLPE insulated power cable systems, XLPE insulation accessories are important components for connecting, maintaining, and insulating cables. They are typically used at intermediate points in the cable to ensure the reliability and safety of the cable system. The main function of intermediate cold-shrink cable accessories is to provide cable connection, insulation, and protection to prevent damage, contamination, and electrical faults at cable connection points. While the insulation performance of XLPE material is generally sufficient under normal voltage conditions, under high voltage and high-current conditions, factors such as uneven electric field, heat accumulation, or mechanical stress can cause problems in the cable insulation layer. Localized overheating can lead to current breakdown, especially inside the cable or at the interface where the cable contacts accessories. Electric field concentration can easily cause excessively high local electric field strength, resulting in electrical insulation damage and current breakdown. In addition, due to the cross-linked structure of cross-linked polyethylene materials, although they have high thermal stability and electrical insulation performance, under the action of high-strength electric fields, local deterioration of molecular chains or uneven stress distribution can still cause mechanical damage to the cable insulation layer. Excessively high local electric field strength may promote electrical breakdown, forming a current path that allows current to pass directly through the insulation layer, leading to local failure or complete breakage of the cable. This phenomenon not only affects the normal operation of the cable but may also cause fires or other safety accidents. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing a flywheel energy storage cable and the cable itself, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for manufacturing a flywheel energy storage cable is provided, the method comprising the following steps:

[0005] The SS100 uses a stranding machine to strand the power core and control core into a standard conductor;

[0006] S200 uses an extruder to extrude a conductor shielding layer onto the outside of a standard conductor;

[0007] S300, mark the trap area of ​​the conductor shielding layer, and correct the conductor shielding layer according to the trap area;

[0008] S400 uses a wrapping machine to wrap a layer of metal strip around the outside of the insulating shielding layer.

[0009] The S500 uses an extruder to extrude an outer sheath onto the outside of a metal strip.

[0010] Furthermore, in S100, the specific method for twisting the power core and control core into a standard conductor using a stranding machine is as follows: the power core and control core are twisted together in multiple strands using a stranding machine to form a standard conductor.

[0011] Furthermore, in S200, the specific method for extruding a conductor shielding layer outside a standard conductor using an extruder is as follows: a conductor shielding layer composed of a mixture of cross-linked polyethylene, silica, and antioxidant is extruded into the gap between the standard power core and control core using an extruder. An insulating layer with a thickness of 2.7 mm is wrapped around the outside of the conductor shielding layer by extrusion. After the first extrusion and cooling, a resin strip is spirally wound around the outside to form a support layer. Then, a second extrusion is performed, and an insulating shielding layer is wrapped around the outside of the support layer. The insulating shielding layer and the support layer are simultaneously extruded to wrap around the outside of the insulation layer, so that the support layer is extruded into the conductor shielding layer.

[0012] Cross-linked polyethylene (XLPE) materials generally meet insulation requirements under normal voltage conditions. However, under high voltage and strong current conditions, the cable insulation layer may experience localized overheating due to factors such as uneven electric field, heat accumulation, or mechanical stress, leading to current breakdown. This is especially true inside the cable or at the interface where the cable contacts accessories, where electric field concentration can easily lead to excessively high local electric field strength, causing electrical insulation damage and resulting in current breakdown. Furthermore, due to the cross-linked structure of XLPE materials, despite their high thermal stability and electrical insulation performance, under high-intensity electric fields, localized deterioration of molecular chains or uneven stress distribution can still cause mechanical damage to the cable insulation layer. Excessively high local electric field strength may promote electrical breakdown, forming a current path that allows current to pass directly through the insulation layer, leading to partial failure or complete breakage of the cable. This phenomenon not only affects the normal operation of the cable but may also cause fires or other safety accidents.

[0013] Furthermore, in S300, the trap regions of the conductor shielding layer are marked, and the specific method for correcting the conductor shielding layer based on the trap regions is as follows:

[0014] The conductor shielding layer was obtained by 3D scanning. The dimensions of the conductor shielding layer were obtained. The material parameters of the shielding layer were imported into Blender software to form the geometric model of the conductor shielding layer. The geometric model was subjected to stress simulation in Blender. The calculation domain was set to 314.7mm×314.7mm×180mm (length×width×height), and the calculation time step was 0.001s. The model was meshed according to the shape characteristics of the cable. Multiple stress distribution maps of the conductor shielding layer were periodically obtained. The first and last stress distribution maps of the conductor shielding layer were obtained.

[0015] The Sobel edge algorithm is used to divide the stress distribution map of the conductor shielding layer obtained in the first time into multiple stress sub-regions. The average stress value of each stress sub-region and the average value of all stress sub-regions are calculated. The region with the largest average stress value among all stress sub-regions with values ​​greater than the average value is called Trap, and the region with the smallest average field strength is called Trak.

[0016] Obtain the most recently acquired stress distribution map of the conductor shielding layer. Use the Sobel edge algorithm to divide the most recently acquired stress distribution map of the conductor shielding layer into multiple sub-regions. Calculate the average stress value in all sub-regions and mark the sub-region with the largest average stress value as A. max The subregion with the smallest average stress is marked as A. min ;

[0017] The Trap and Trak regions in the first obtained conductor shielding layer stress distribution map are projected onto the most recently obtained conductor shielding layer stress distribution map as the Trap' and Trak' regions, respectively, and A is marked. max The point corresponding to the maximum stress in the region is P1, A min The point corresponding to the maximum stress in the region is P2. The point projected from the point corresponding to the maximum stress in the Trap region to the Trap' region is P3. The point projected from the point corresponding to the maximum stress in the Trak region to the Trak' region is P4. The quadrilateral region formed by the four points P1, P2, P3, and P4 is the stress diffusion region.

[0018] Due to the working environment of cables, they need to be deformed and subjected to stress. The deformation point will be subjected to a large external force. If the external force exceeds the cable's stress limit, or if the deformation point becomes a weak point due to material defects in the cable, it will lead to breakage during use and affect the cable's service life. The above steps mark the stress diffusion area by periodically obtaining the stress change of the cable. Since the cable will undergo a diffusion phenomenon after being subjected to pressure, this phenomenon is closely related to the internal structure and is manifested externally as the diffusion of stress value. Therefore, the stress diffusion area can reflect the distribution of the internal structure of the cable.

[0019] The geometric model was imported into Blender for simulation experiments. A phase voltage of 110kV (0-100ms) was applied. Outside the insulation layer, there was a lead alloy sheath and a steel wire armor layer. Grounding was performed in engineering, and the potential was 0. A zero potential load was applied. The calculation domain was set to 314.7mm×314.7mm×180mm (length×width×height). The model was meshed according to the shape characteristics of the cable. Multiple electric field distribution maps of the conductor shielding layer were periodically obtained. The first and last electric field distribution maps of the conductor shielding layer were obtained.

[0020] The Sobel edge algorithm is used to divide the electric field distribution map of the conductor shield layer obtained in the first time into multiple field strength sub-regions. The average field strength of each field strength sub-region and the average value of all field strength sub-regions are calculated. The region with the largest average field strength of all field strength sub-regions with a field strength greater than the average value is called Srap, and the region with the smallest average field strength is called Srak.

[0021] Obtain the electric field distribution map of the conductor shielding layer acquired at the most recent time. Use the Sobel edge algorithm to divide the electric field distribution map of the conductor shielding layer acquired at the most recent time into multiple sub-regions. Calculate the average electric field strength in all sub-regions and mark the sub-region with the largest average electric field strength as B. max The subregion with the smallest average field strength is labeled B. min ;

[0022] The Srap and Srak regions in the first acquired conductor shielding electric field distribution map are projected onto the most recently acquired conductor shielding electric field distribution map as the Srap' and Srak' regions, respectively, and B is marked. max The point corresponding to the maximum electric field strength in the region is Q1, B mi The point corresponding to the maximum field strength in region n is Q2. The point corresponding to the maximum field strength in region Srap is projected onto region Srap' as Q3. The point corresponding to the maximum field strength in region Srak is projected onto region Srak' as Q4. The quadrilateral region formed by the four points Q1, Q2, Q3, and Q4 is the field strength diffusion region.

[0023] Because of the non-uniformity of electrical energy transmission within a unit of time, a non-uniform electric field is generated inside the cable per unit time. Breakdown is more likely to occur in areas with large field strength gradients and large field strengths, affecting the service life of the cable. At the same time, when cross-linked polyethylene cables use cross-linked polyethylene as the insulation layer, if there are gaps or voids in the material structure, breakdown will also occur at these defects. The field strength diffusion area can reflect the current transmission situation when the cable transmits electrical energy, especially the transmission situation inside the cable when there are gaps in the transmission of electrical energy or when there are peaks in the propagation of electrical energy.

[0024] The projection of the stress diffusion region onto all the obtained stress distribution maps of the conductor shielding layer is called the stress diffusion projection region SP. All stress diffusion projection regions SP are arranged according to the acquisition time, and j is used as the sequence number of the stress diffusion projection region. j This represents the i-th stress diffusion projection region;

[0025] The projection of the field strength diffusion region onto the electric field distribution maps of all acquired conductor shielding layers is defined as the field strength diffusion projection region SQ. All field strength diffusion projection regions are arranged according to the acquisition time, with j as the sequence number of the stress diffusion projection region. j This represents the i-th field intensity diffusion projection region;

[0026] Within the range of values ​​for j, calculate the stress diffusion projection region SP. j average stress j The stress magnitude of the j-th stress diffusion projection region is obtained by iterating through all stress diffusion projection regions using the formula... Calculate the stress transfer capacity of the j-th stress diffusion projection region, where N represents the number of stress diffusion projection regions. If the following conditions are met within the range of j: CHA j <|stress j -stress j-1 If |, then the stress diffusion region is considered to have a stress transmission barrier, and the stress diffusion region is marked as a trap region;

[0027] Similarly, within the range of values ​​for j, the field intensity diffusion projection region SQ is calculated. j average electric field strength j As the magnitude of the field strength in the j-th field strength diffusion projection region, the magnitude of the field strength in all field strength diffusion projection regions is obtained through the formula... Calculate the field strength transfer capability of the j-th field strength diffusion projection region, where N represents the number of field strength diffusion projection regions. If all values ​​within the range of j satisfy: CHB j <|electric j -electric j-1 If |, then the field strength diffusion region is considered to be an obstacle to field strength transmission, and the field strength diffusion region is marked as a trap region;

[0028] The above method obtains the projected regions of the stress diffusion region and field strength diffusion region in the stress distribution map and field strength distribution map at all times. The above formula, by calculating the stress difference and field strength difference of the projected regions between adjacent times, can reflect the stress and field strength changes of the cable under high voltage and high electric field conditions, and can reflect the cable's tolerance under these conditions. If the stress difference of the projected regions between adjacent times continues to increase, that is, if the CHA is satisfied throughout the entire acquisition period... j <|stress j -stress j-1 | indicates that the projected area cannot properly transmit the single-point high voltage to other areas. Continuous exposure to high voltage can easily cause structural damage in that area. Similarly, if the field strength difference between adjacent projected areas continues to increase, meaning the CHB condition is met throughout the entire acquisition period… j <|electric j -electric j-1 |Continuous exposure to a high-voltage environment is highly likely to cause current breakdown in this area.

[0029] The above methods reflect the withstand capability of the projected region under high voltage and strong electric environment by judging the stress change and field strength change of the projected region throughout the entire cycle. However, if the current breakdown is caused by structural damage, it means that structural damage occurred first during the pressure application process, resulting in electrical treeing effect. This causes the current at the tree to be much higher than in other areas, thus leading to current breakdown. See reference: Zhu Xi. Research on the correlation characteristics of electrical treeing and partial discharge in AC and DC electric fields of high voltage cable insulation [D]. Shanghai Jiaotong University, 2021. DOI:10.27307 / d.cnki.gsjtu.2021.000122. In this case, the conditions in the above methods are no longer met: CHA j <|stress j -stress j-1 |Or condition: CHB j <|electric j -electric j-1 If this is not done correctly, some detection may be missed. To solve this problem, the present invention proposes the following correction method:

[0030] Within the range of values ​​for j, the stress transfer capability CHA of all stress diffusion projection regions is traversed. If stress1 is satisfied... <stress N And CHA1>CHA N At that time, compare stress in sequence. j With stress j+1 The first one to satisfy stress jstress j+1 The corresponding projected region is marked as the stress reversal region, and the maximum stress value in the stress reversal region is marked as P. max P max The corresponding point is A, and the minimum value greater than the average stress is P. min P min The corresponding point is B. Connecting point A and point B forms line segment Line1. With the midpoint of Line1 as the center and half the length of Line1 as the radius, draw circle C1. Iterate through all points within C1 and discard all stress values ​​greater than (P). max +P min Find the points of ) / 2, and fit the remaining points into curve V1 using curve fitting.

[0031] Similarly, within the range of j, the field strength transfer capability CHB of c in all field strength diffusion projection regions is traversed. If electric1 is satisfied... <electric N And CHB1>CHB N At that time, compare electric in sequence j With electric j+1 The first one that satisfies electric j electric j+1 The corresponding projection region is marked as the field inversion region, and the maximum field strength in the field inversion region is marked as Q. max Q max The corresponding point is C, and the minimum value greater than the average field strength is Q. min Q min The corresponding point is D. Connect point C and point D to form line segment Line2. With the midpoint of Line2 as the center and the length of Line2 / 2 as the radius, draw a circle C2. Iterate through all points contained in C2 and discard all electric field strength values ​​less than (Q). max +Q min The points are calculated as ) / 2, and the remaining points are fitted to curve V2 using curve fitting. Curve V1 is then projected onto the field inversion region containing curve V2 to obtain projection V1', which is then calculated using the formula... Calculate the correlation coefficient BCH between curves V1 and V2, where MA(V1',V2) represents the maximum distance between all points on the projection V1' and points on V2, MI(V1',V2) represents the minimum distance between all points on the projection V1' and points on V2, ∑|MAX(V1′,V2)―MIN(V1′,V2)| represents the sum of the differences between the maximum distance between each point on the projection V1' and each point on V2 and the minimum distance between each point on the projection V1' and each point on V2, MAX(·) represents the maximum distance between each point on one curve and each point on another curve, and MIN(·) represents the minimum distance between each point on one curve and each point on another curve. If the correlation coefficient BCH between curves V1 and V2 is zero, it is considered that a local structural failure has occurred, and current breakdown occurs at the failure point. The stress diffusion projection region and the field strength diffusion projection region are marked as trap regions.

[0032] Furthermore, the specific method for correcting the conductor shielding layer based on the defective area is as follows: the defective area of ​​the cable is repaired using an extruder, and the working parameters are consistent with the working parameters corresponding to the first extrusion.

[0033] The above method, by marking stress reversal regions and field strength reversal regions, can identify areas where the structure has already failed (because under high pressure, assuming the structure is not failed, the stress trend changes continuously with the applied force trend; if the structure fails, the stress capacity at the failure point will decrease sharply, exhibiting a reversal phenomenon in time sequence). If electrical dendrites occur at the failure point, the field strength there will be much greater than in other areas, showing a severe imbalance in distribution. Since the shape of the electrical dendrites generated at the structural failure point will be very similar to the shape of the structural failure, but their distribution is irregular, the formula above... Some cases can indicate that the location of the electrical tree is not overlapping with the damaged area. Some of these formulas can reflect situations where the location of electrical treeing overlaps with the damaged area. Overall, the above formulas can accurately detect the risk of current breakdown after structural damage to the cable.

[0034] Furthermore, in S400, the specific method of wrapping a metal strip around the outside of the insulating shielding layer using a wrapping machine is as follows: a metal strip is wrapped around the outside of the wrapping layer using a wrapping machine, and the metal strip completely wraps the outside of the insulating shielding layer by overlapping wrapping, with an overlap rate of 23%, and the metal strip is an aluminum alloy strip.

[0035] Furthermore, in S500, the specific method for forming an outer sheath by extruding the metal strip outside the metal strip using an extruder after the metal strip is wound is as follows:

[0036] After the metal strip is wound, a layer of non-woven fabric is wrapped around it, with a wrapping coverage of 20%. Then, a low-smoke halogen-free flame-retardant polyolefin is extruded on the outside of the wrapping material to form an outer sheath. The non-woven fabric is made by wrapping a layer of non-woven fabric with a thickness of 0.2 mm and a width of 50 mm. The wrapping direction of the non-woven fabric is right-handed, and the wrapping pitch of the non-woven fabric is 32 mm. The non-woven fabric material is polyester fiber.

[0037] Beneficial Effects: This invention, by acquiring a three-dimensional digital model of the cable and combining it with high-voltage electric field simulation analysis, can accurately assess the stress and electric field distribution of the cable under high-voltage conditions. Through comprehensive analysis of stress distribution maps and electric field distribution maps, it can effectively identify weak areas in the cable that are prone to damage and current breakdown. For these high-risk areas, structural optimization and electrical corrections can be performed to improve the mechanical strength and electrical insulation performance of the cable, thereby controlling the probability of cable failure. In addition, this invention establishes a response model that can monitor electrical treeing caused by structural damage in real time and accurately identify and locate defect areas, thereby significantly improving the sensitivity and accuracy of defect detection and ensuring the long-term stability and safety of the cable in high-voltage working environments. Attached Figure Description

[0038] Figure 1 The diagram shows a flowchart of a method for manufacturing a flywheel energy storage cable; Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] Example 1:

[0041] Figure 1 The diagram shows a flowchart of a method for manufacturing a flywheel energy storage cable.

[0042] Reference Figure 1 This invention proposes a method for manufacturing a flywheel energy storage cable, the method comprising the following steps:

[0043] S100 uses a stranding machine to strand the power core and control core into a standard conductor;

[0044] S200 uses an extruder to extrude a conductor shielding layer onto the outside of a standard conductor;

[0045] S300, mark the trap area of ​​the conductor shielding layer, and correct the conductor shielding layer according to the trap area;

[0046] S400 uses a wrapping machine to wrap a layer of metal strip around the outside of the insulating shielding layer.

[0047] The S500 uses an extruder to extrude an outer sheath onto the outside of a metal strip.

[0048] Furthermore, the stranding machine is an SJ-40 unidirectional cable stranding machine.

[0049] Furthermore, the extruder is a TSE-75 / 150 multilayer extruder.

[0050] Furthermore, the wrapping machine is the YW-Auto-1200 fully automatic wrapping machine.

[0051] Furthermore, in S100, the specific method for twisting the power core and control core into a standard conductor using a stranding machine is as follows: the power core and control core are twisted together in multiple strands using a stranding machine to form a standard conductor.

[0052] Furthermore, the stranding machine has a stranding speed of 40 m / min, a stranding direction of reverse stranding, 3 strands, a stranding angle of 25°, and a stranding density of 95%.

[0053] Furthermore, in S200, the specific method for extruding a conductor shielding layer outside a standard conductor using an extruder is as follows: a conductor shielding layer composed of a mixture of cross-linked polyethylene, silica, and antioxidant is extruded into the gap between the standard power core and control core using an extruder. An insulating layer with a thickness of 2.7 mm is wrapped around the outside of the conductor shielding layer by extrusion. After the first extrusion and cooling, a resin strip is spirally wound around the outside to form a support layer. Then, a second extrusion is performed, and an insulating shielding layer is wrapped around the outside of the support layer. The insulating shielding layer and the support layer are simultaneously extruded to wrap around the outside of the insulation layer, so that the support layer is extruded into the conductor shielding layer.

[0054] Furthermore, the extruder operating parameters for the first extrusion are as follows: the extrusion temperature of the conductor shielding layer is set to 180℃, the extrusion speed is 3m / min, the extrusion pressure is 40MPa, the cooling temperature is set to 30℃, and the tension is maintained at 30N.

[0055] Furthermore, the extruder operating parameters for the second extrusion are as follows: the temperature of the support layer is set to 190℃, the extrusion speed is 2m / min, the extrusion pressure is 42MPa, and the tension is maintained at 35N.

[0056] Furthermore, in S300, the trap regions of the conductor shielding layer are marked, and the specific method for correcting the conductor shielding layer based on the trap regions is as follows:

[0057] The conductor shielding layer was obtained by 3D scanning. The dimensions of the conductor shielding layer were obtained. The material parameters of the shielding layer were imported into Blender software to form the geometric model of the conductor shielding layer. The geometric model was subjected to stress simulation in Blender. The calculation domain was set to 314.7mm×314.7mm×180mm (length×width×height), and the calculation time step was 0.001s. The model was meshed according to the shape characteristics of the cable. Multiple stress distribution maps of the conductor shielding layer were periodically obtained. The first and last stress distribution maps of the conductor shielding layer were obtained.

[0058] The Sobel edge algorithm is used to divide the stress distribution map of the conductor shielding layer obtained in the first time into multiple stress sub-regions. The average stress value of each stress sub-region and the average value of all stress sub-regions are calculated. The region with the largest average stress value among all stress sub-regions with values ​​greater than the average value is called Trap, and the region with the smallest average field strength is called Trak.

[0059] Obtain the most recently acquired stress distribution map of the conductor shielding layer. Use the Sobel edge algorithm to divide the most recently acquired stress distribution map of the conductor shielding layer into multiple sub-regions. Calculate the average stress value in all sub-regions and mark the sub-region with the largest average stress value as A. max The subregion with the smallest average stress is marked as A. min ;

[0060] The Trap and Trak regions in the first obtained conductor shielding layer stress distribution map are projected onto the most recently obtained conductor shielding layer stress distribution map as the Trap' and Trak' regions, respectively, and A is marked. max The point corresponding to the maximum stress in the region is P1, A min The point corresponding to the maximum stress in the region is P2. The point projected from the point corresponding to the maximum stress in the Trap region to the Trap' region is P3. The point projected from the point corresponding to the maximum stress in the Trak region to the Trak' region is P4. The quadrilateral region formed by the four points P1, P2, P3, and P4 is the stress diffusion region.

[0061] The geometric model was imported into Blender for simulation experiments. A phase voltage of 110kV (0-100ms) was applied. Outside the insulation layer, there was a lead alloy sheath and a steel wire armor layer. Grounding was performed in engineering, and the potential was 0. A zero potential load was applied. The calculation domain was set to 314.7mm×314.7mm×180mm (length×width×height). The model was meshed according to the shape characteristics of the cable. Multiple electric field distribution maps of the conductor shielding layer were periodically obtained. The first and last electric field distribution maps of the conductor shielding layer were obtained.

[0062] The Sobel edge algorithm is used to divide the electric field distribution map of the conductor shield layer obtained in the first time into multiple field strength sub-regions. The average field strength of each field strength sub-region and the average value of all field strength sub-regions are calculated. The region with the largest average field strength of all field strength sub-regions with a field strength greater than the average value is called Srap, and the region with the smallest average field strength is called Srak.

[0063] Obtain the electric field distribution map of the conductor shielding layer acquired at the most recent time. Use the Sobel edge algorithm to divide the electric field distribution map of the conductor shielding layer acquired at the most recent time into multiple sub-regions. Calculate the average electric field strength in all sub-regions and mark the sub-region with the largest average electric field strength as B. max The subregion with the smallest average field strength is labeled B. min ;

[0064] The Srap and Srak regions in the first acquired conductor shielding electric field distribution map are projected onto the most recently acquired conductor shielding electric field distribution map as the Srap' and Srak' regions, respectively, and B is marked. max The point corresponding to the maximum electric field strength in the region is Q1, B mi The point corresponding to the maximum field strength in region n is Q2. The point corresponding to the maximum field strength in region Srap is projected onto region Srap' as Q3. The point corresponding to the maximum field strength in region Srak is projected onto region Srak' as Q4. The quadrilateral region formed by the four points Q1, Q2, Q3, and Q4 is the field strength diffusion region.

[0065] The projection of the stress diffusion region onto all the obtained stress distribution maps of the conductor shielding layer is called the stress diffusion projection region SP. All stress diffusion projection regions SP are arranged according to the acquisition time, and j is used as the sequence number of the stress diffusion projection region. j This represents the i-th stress diffusion projection region;

[0066] The projection of the field strength diffusion region onto the electric field distribution maps of all acquired conductor shielding layers is defined as the field strength diffusion projection region SQ. All field strength diffusion projection regions are arranged according to the acquisition time, with j as the sequence number of the stress diffusion projection region. j This represents the i-th field intensity diffusion projection region;

[0067] Within the range of values ​​for j, calculate the stress diffusion projection region SP. j average stress j The stress magnitude of the j-th stress diffusion projection region is obtained by iterating through all stress diffusion projection regions using the formula... Calculate the stress transfer capacity of the j-th stress diffusion projection region, where N represents the number of stress diffusion projection regions. If the following conditions are met within the range of j: CHA j<|stress j -stress j-1 If |, then the stress diffusion region is considered to have a stress transmission barrier, and the stress diffusion region is marked as a trap region;

[0068] Similarly, within the range of values ​​for j, the field intensity diffusion projection region SQ is calculated. j average electric field strength j As the magnitude of the field strength in the j-th field strength diffusion projection region, the magnitude of the field strength in all field strength diffusion projection regions is obtained through the formula... Calculate the field strength transfer capability of the j-th field strength diffusion projection region, where N represents the number of field strength diffusion projection regions. If all values ​​within the range of j satisfy: CHB j <|electric j -electric j-1 If |, then the field strength diffusion region is considered to be an obstacle to field strength transmission, and the field strength diffusion region is marked as a trap region;

[0069] Furthermore, the specific method for correcting the conductor shielding layer based on the defective area is as follows: the defective area of ​​the cable is repaired using an extruder, and the working parameters are consistent with the working parameters corresponding to the first extrusion.

[0070] Furthermore, in S400, the specific method of wrapping a metal strip around the outside of the insulating shielding layer using a wrapping machine is as follows: a metal strip is wrapped around the outside of the wrapping layer using a wrapping machine, and the metal strip completely wraps the outside of the insulating shielding layer by overlapping wrapping, with an overlap rate of 23%, and the metal strip is an aluminum alloy strip.

[0071] Furthermore, in S500, the specific method for forming an outer sheath by extruding the metal strip outside the metal strip using an extruder after the metal strip is wound is as follows:

[0072] After the metal strip is wound, a layer of non-woven fabric is wrapped around it, with a wrapping coverage of 20%. Then, a low-smoke halogen-free flame-retardant polyolefin is extruded on the outside of the wrapping material to form an outer sheath. The non-woven fabric is made by wrapping a layer of non-woven fabric with a thickness of 0.2 mm and a width of 50 mm. The wrapping direction of the non-woven fabric is right-handed, and the wrapping pitch of the non-woven fabric is 32 mm. The non-woven fabric material is polyester fiber.

[0073] Example 2

[0074] This embodiment 2 replaces the method of marking the trap region of the conductor shielding layer based on embodiment 1, specifically as follows:

[0075] Within the range of values ​​for j, the stress transfer capability CHA of all stress diffusion projection regions is traversed. If stress1 is satisfied... <stress N And CHA1>CHA N At that time, compare stress in sequence. j With stress j+1 The first one to satisfy stress j stress j+1 The corresponding projected region is marked as the stress reversal region, and the maximum stress value in the stress reversal region is marked as P. max P max The corresponding point is A, and the minimum value greater than the average stress is P. min P min The corresponding point is B. Connecting point A and point B forms line segment Line1. With the midpoint of Line1 as the center and half the length of Line1 as the radius, draw circle C1. Iterate through all points within C1 and discard all stress values ​​greater than (P). max +P min Find the points of ) / 2, and fit the remaining points into curve V1 using curve fitting.

[0076] Similarly, within the range of j, the field strength transfer capability CHB of all field strength diffusion projection regions is traversed. If electric1 is satisfied... <electric N And CHB1>CHB N At that time, compare electric in sequence j With electric j+1 The first one that satisfies electric j electric j+1 The corresponding projection region is marked as the field inversion region, and the maximum field strength in the field inversion region is marked as Q. max Q max The corresponding point is C, and the minimum value greater than the average field strength is Q. min Q min The corresponding point is D. Connect point C and point D to form line segment Line2. With the midpoint of Line2 as the center and the length of Line2 / 2 as the radius, draw a circle C2. Iterate through all points contained in C2 and discard all electric field strength values ​​less than (Q). max +Q min The points are calculated as ) / 2, and the remaining points are fitted to curve V2 using curve fitting. Curve V1 is then projected onto the field inversion region containing curve V2 to obtain projection V1', which is then calculated using the formula... Calculate the correlation coefficient BCH between curves V1 and V2, where MA(V1',V2) represents the maximum distance between all points on the projection V1' and points on V2, MI(V1',V2) represents the minimum distance between all points on the projection V1' and points on V2, ∑|MAX(V1′,V2)―MIN(V1′,V2)| represents the sum of the differences between the maximum distance between each point on the projection V1' and each point on V2 and the minimum distance between each point on the projection V1' and each point on V2, MAX(·) represents calculating the maximum distance between each point on one curve and each point on another curve, and MIN(·) represents calculating the minimum distance between each point on one curve and each point on another curve. If the correlation coefficient BCH between curves V1 and V2 is zero, it is considered that a local structural failure has occurred, and current breakdown occurs at the failure point. The stress diffusion projection region and the field strength diffusion projection region are marked as trap regions.

[0077] Comparative example: A cable manufactured using the cable manufacturing method described in Example 1 of a patent application filed on April 22, 2024, with publication number CN118136313B, entitled "High-Temperature Pressure-Resistant Cable for Energy Storage Device and Manufacturing Method Thereof".

[0078] Finished cables were randomly selected from Example 1, Example 2 and Comparative Example. The insulation layer of the sampled cables was cut along the circumference of the cable using a lathe to obtain three samples with a thickness of 230 mm. The lathe, cutting tool and rotation speed were the same for different cables. Power frequency breakdown voltage test was performed on the samples.

[0079] The breakdown AC voltage source used was a frequency-modulated and voltage-regulated partial discharge-free voltage source manufactured by Shanghai Jiate High Voltage Electrical Equipment Co., Ltd., and the test temperature was 105℃. To ensure a uniform electric field distribution between the electrodes, symmetrical columnar stainless steel electrodes with a diameter of 25mm and an edge curvature radius of 3mm were used. During the test, the sample and electrode system were immersed in vegetable insulating oil, which effectively reduced the occurrence of surface flashover during discharge. The experiment was conducted after heating the sample to the specified temperature in an oil bath. Considering the dispersion of sample breakdown, 15 breakdown points were selected for repeated tests, and the equivalent breakdown field strength was calculated based on the Weibull distribution. The experimental results are shown in Table 1.

[0080] Table 1. Results of power frequency breakdown voltage test

[0081] Power frequency breakdown field strength (kV / mm) Shape parameter β Example 1 126.38 29.46 Example 2 138.42 45.52 Comparative Example 114.18 15.75

[0082] Finished cables were randomly selected from Examples 1, 2, and the Comparative Example. Mechanical performance tests were conducted according to GB / T7424.2-2008, including tensile tests, flattening tests, impact tests, repeated bending tests, torsion tests, winding tests, coiling tests, and sheath wear tests. The absolute value of attenuation change and strain magnitude were measured at a wavelength of 1550nm, as specified in YD / T629.1. Simultaneously, the outer sheath was visually inspected for cracks. For each selected finished cable from the Examples and Comparative Example, a 3m sample was taken. The ends of the sample were carefully rounded. A 1m high water column was applied to one end of the sample according to method F5B in GB / T7424.2-2008. After 24 hours, visual observation was performed to check for water overflow at the other end of the sample, excluding the communication metal wire pair and / or feeder wire. The results are shown in Table 2.

[0083] Table 2

[0084]

[0085] Analysis of the breakdown field strength data in Table 1 shows that the breakdown field strengths of Examples 1 and 2 are higher than those of the comparative example. The higher the breakdown field strength, the stronger the cable's ability to withstand high voltage. This indicates that the present invention can detect structural defects in the cable and compensate for these defects through correction, thereby improving the cable's withstand capability. The breakdown field strength of Example 2 is higher than that of Example 1 because Example 2 considers not only the structure's withstand capability for high voltage but also the situation where the voltage withstand capability is significantly weakened due to structural damage. Observing the shape parameter data in Table 1, it can be seen that the shape parameters of Examples 1 and 2 are higher than those of the comparative example. The shape parameter reflects the distribution of breakdown time and field strength. If the shape parameter is lower, it indicates an irregular distribution, showing a random distribution. If the shape parameter is higher, it indicates a more concentrated distribution. The present invention transforms the breakdown problem into a controllable problem by correcting defects. Since the comparative example does not have a correction strategy, the breakdown problem largely depends on material defects. Material defect problems are irregular in their manifestation with environmental factors, and the problems become uncontrollable.

[0086] Analysis of the attenuation change and strain data in Table 2 shows that the attenuation change corresponding to Example 1 and Example 2 is lower than that of the comparative example. It can be seen that the cable made by the method of the present invention still has strong mechanical strength after facing high-intensity tension, flattening, impact, repeated bending, torsion and winding. The degree of deformation is much smaller than that of the comparative example. The protective sheath has no cracks and no water leakage. It is evident that the cable made according to the present invention has the bearing capacity and superiority in high-intensity environments.

[0087] In summary, this invention can effectively identify weak areas in cables that are prone to damage and current breakdown. For these high-risk areas, structural optimization and electrical modifications are performed to improve the mechanical strength and electrical insulation performance of the cable, thereby controlling the failure probability of the cable and ensuring the long-term stability and safety of the cable in high-voltage working environments.

[0088] Although the invention has been described in considerable detail and particularly with regard to several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment, thereby effectively covering the intended scope of the invention. Furthermore, the invention has been described above with respect to embodiments foreseeable by the inventors in order to provide a useful description, and non-substantial modifications to the invention that have not yet been foreseen may still represent equivalent modifications.

Claims

1. A method for manufacturing a flywheel energy storage cable, characterized in that, The method includes the following steps: S100 uses a stranding machine to strand the power core and control core into a standard conductor; S200 uses an extruder to extrude a conductor shielding layer onto the outside of a standard conductor; S300, mark the trap area of ​​the conductor shielding layer, and correct the conductor shielding layer according to the trap area; S400 uses a wrapping machine to wrap a layer of metal strip around the outside of the insulating shielding layer; S500 uses an extruder to form an outer sheath by extruding a metal strip on the outside. In S300, the trap regions of the conductor shielding layer are marked. The method for correcting the conductor shielding layer based on the trap regions is as follows: use 3D scanning of the conductor shielding layer to obtain the three-dimensional model size of the conductor shielding layer, import the shielding layer material parameters into Blender software to form the geometric model of the conductor shielding layer, perform stress simulation on the geometric model in Blender, periodically obtain multiple stress distribution maps of the conductor shielding layer, and obtain the first obtained stress distribution map of the conductor shielding layer and the last obtained stress distribution map of the conductor shielding layer. The Sobel edge algorithm is used to divide the stress distribution map of the conductor shielding layer obtained in the first time into multiple stress sub-regions. The average stress value of each stress sub-region and the average value of all stress sub-regions are calculated. The region with the largest average stress value among all stress sub-regions with values ​​greater than the average value is marked as Trap, and the region with the smallest average stress value is marked as Trak. Obtain the most recently acquired stress distribution map of the conductor shielding layer. Use the Sobel edge algorithm to divide the most recently acquired stress distribution map of the conductor shielding layer into multiple sub-regions. Calculate the average stress value in all sub-regions and mark the sub-region with the largest average stress value as A. max The subregion with the smallest average stress is marked as A. min ; The Trap and Trak regions in the first obtained conductor shielding layer stress distribution map are projected onto the most recently obtained conductor shielding layer stress distribution map as the Trap' and Trak' regions, respectively, and A is marked. max The point corresponding to the maximum stress in the region is P1, A min The point corresponding to the maximum stress in the region is P2. The point projected from the point corresponding to the maximum stress in the Trap region to the Trap' region is P3. The point projected from the point corresponding to the maximum stress in the Trak region to the Trak' region is P4. The quadrilateral region formed by the four points P1, P2, P3, and P4 is marked as the stress diffusion region. The geometric model was imported into Blender for simulation experiments. Multiple electric field distribution maps of the conductor shielding layer were periodically acquired, including the first and last acquired electric field distribution maps of the conductor shielding layer. The Sobel edge algorithm is used to divide the electric field distribution map of the conductor shield layer obtained in the first time into multiple field strength sub-regions. The average field strength of each field strength sub-region and the average value of all field strength sub-regions are calculated. All field strength sub-regions with a value greater than the average value are filtered out. The region with the largest average field strength among all field strength sub-regions with a value greater than the average value is marked as Srap, and the region with the smallest average field strength is marked as Srak. Obtain the electric field distribution map of the conductor shielding layer acquired at the most recent time. Use the Sobel edge algorithm to divide the electric field distribution map of the conductor shielding layer acquired at the most recent time into multiple sub-regions. Calculate the average electric field strength in all sub-regions and mark the sub-region with the largest average electric field strength as B. max The subregion with the smallest average field strength is labeled B. min ; The Srap and Srak regions in the first acquired conductor shielding electric field distribution map are projected onto the most recently acquired conductor shielding electric field distribution map as the Srap' and Srak' regions, respectively, and B is marked. max The point corresponding to the maximum electric field strength in the region is Q1, B min The point corresponding to the maximum field strength in the region is Q2. The point corresponding to the maximum field strength in the Srap region is projected onto the Srap' region as Q3. The point corresponding to the maximum field strength in the Srak region is projected onto the Srak' region as Q4. The quadrilateral region formed by the four points Q1, Q2, Q3, and Q4 is marked as the field strength diffusion region. The projection of the stress diffusion region onto all the obtained stress distribution maps of the conductor shielding layer is called the stress diffusion projection region SP. All stress diffusion projection regions SP are arranged according to the acquisition time, and j is used as the sequence number of the stress diffusion projection region. j This represents the j-th stress diffusion projection region; The projection of the field strength diffusion region onto the electric field distribution maps of all acquired conductor shielding layers is defined as the field strength diffusion projection region SQ. All field strength diffusion projection regions are arranged according to the acquisition time, with j as the sequence number of the stress diffusion projection region. j This represents the j-th field strength diffusion projection region; Within the range of values ​​for j, calculate the stress diffusion projection region SP. j average stress j The stress magnitude of the j-th stress diffusion projection region is obtained by iterating through all stress diffusion projection regions using the formula... Calculate the stress transfer capacity of the j-th stress diffusion projection region, where N represents the number of stress diffusion projection regions. If the following conditions are met within the range of j: CHA j <|stress j -stress j-1 If |, then it is considered that there is a stress transmission barrier in the stress diffusion region, and the stress diffusion region is marked as a trap region; Similarly, within the range of values ​​for j, the field intensity diffusion projection region SQ is calculated. j average electric field strength j As the magnitude of the field strength in the j-th field strength diffusion projection region, the magnitude of the field strength in all field strength diffusion projection regions is obtained through the formula... Calculate the field strength transfer capability of the j-th field strength diffusion projection region, where N represents the number of field strength diffusion projection regions. If all values ​​within the range of j satisfy: CHB j <|electric j -electric j-1 If the field strength diffusion area is considered to be a field strength transmission obstacle, then the field strength diffusion area is marked as a trap area. The specific method for modifying the conductor shielding layer according to the trap area is as follows: use an extruder to repair the cable trap area, and the working parameters are the same as the working parameters corresponding to the first extrusion.

2. The method for manufacturing a flywheel energy storage cable according to claim 1, characterized in that, In S100, the method of twisting the power core and control core into a standard conductor using a stranding machine is as follows: the power core and control core are twisted together in multiple strands using a stranding machine to form a standard conductor.

3. The method for manufacturing a flywheel energy storage cable according to claim 2, characterized in that, In S200, the method of extruding a conductor shielding layer outside a standard conductor using an extruder is as follows: a conductor shielding layer composed of a mixture of cross-linked polyethylene, silica, and antioxidant is extruded into the gap between the standard power core and control core using an extruder. An insulating layer with a thickness of 2.7 mm is wrapped around the outside of the conductor shielding layer by extrusion. After the first extrusion and cooling, a resin strip is spirally wound around the outside to form a support layer. Then, a second extrusion is performed, and an insulating shielding layer is wrapped around the outside of the support layer. The insulating shielding layer and the support layer are simultaneously extruded to wrap around the outside of the insulation layer, so that the support layer is extruded into the conductor shielding layer.

4. The method for manufacturing a flywheel energy storage cable according to claim 3, characterized in that, The method of marking the trap regions of the conductor shielding layer is replaced with: Within the range of values ​​for j, the stress transfer capability CHA of all stress diffusion projection regions is traversed. If stress1 is satisfied... <stress N And CHA1>CHA N At that time, compare stress in sequence. j With stress j+1 The first one to satisfy stress j stress j+1 The corresponding projected region is marked as the stress reversal region, and the maximum stress value in the stress reversal region is marked as P. max P max The corresponding point is A, and the minimum value greater than the average stress is P. min P min The corresponding point is B. Connecting point A and point B forms line segment Line1. With the midpoint of Line1 as the center and half the length of Line1 as the radius, draw circle C1. Iterate through all points within C1 and discard all stress values ​​greater than (P). max +P min Find the points of ) / 2, and fit the remaining points into curve V1 using curve fitting; Within the range of j, the field strength transfer capability CHB of all field strength diffusion projection regions is traversed. If electric1 is satisfied... <electric N And CHB1>CHB N At that time, compare electric in sequence j With electric j+1 The first one that satisfies electric j electric j+1 The corresponding projection region is marked as the field inversion region, and the maximum field strength in the field inversion region is marked as Q. max Q max The corresponding point is C, and the minimum value greater than the average field strength is Q. min Q min The corresponding point is D. Connect point C and point D to form line segment Line2. With the midpoint of Line2 as the center and the length of Line2 / 2 as the radius, draw a circle C2. Iterate through all points contained in C2 and discard all electric field strength values ​​less than (Q). max +Q min The points are divided into 2 and the remaining points are fitted to curve V2 using curve fitting; curve V1 is projected onto the field inversion region where curve V2 is located to obtain projection V1', which is obtained by using the formula Calculate the correlation coefficient BCH between curves V1 and V2, where MA(V1',V2) represents the maximum distance between all points on the projection V1' and points on V2, and MI(V1',V2) represents the minimum distance between all points on the projection V1' and points on V2. This represents the sum of the differences between the maximum distance between each point on projection V1' and each point on V2 and the minimum distance between each point on projection V1' and each point on V2. MAX(·) represents the calculation of the maximum distance between each point on one curve and each point on another curve, and MIN(·) represents the calculation of the minimum distance between each point on one curve and each point on another curve. If the correlation coefficient BCH between curve V1 and curve V2 is zero, it is considered that a local structural failure has occurred, and current breakdown occurs at the failure point. The stress diffusion projection region and the field strength diffusion projection region are marked as trap regions.

5. A cable, characterized in that, It is manufactured by the method for preparing a flywheel energy storage cable according to any one of claims 1 to 4.

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