Integrated coating for abnormal discharge monitoring and self-repairing of cable and preparation method of integrated coating

Abstract

The invention discloses an integrated coating for abnormal discharge monitoring and self-repairing of a cable. The invention further discloses a preparation method of the cable abnormal discharge monitoring and self-repairing integrated coating. The preparation method is implemented according to the following steps: step 1, preparing a repairing agent-loaded microcapsule; step 2, adding the repairing agent-loaded microcapsule into the outer coating layer solution to prepare a repairing agent-loaded microcapsule coated with a piezoelectric-based material; step 3, washing the repairing agent-loaded microcapsule coated with the piezoelectric-based material in deionized water to remove the pore-forming agent, and performing freeze drying treatment to obtain a repairing agent-loaded microcapsule coated with a porous piezoelectric-based material; and step 4, mixing and stirring the repairing agent-loaded microcapsule coated with the porous piezoelectric-based material obtained in the step 3 with a coating carrier, a dispersing agent, a curing agent and a catalyst according to a set proportion to obtain the coating. According to the cable abnormal discharge monitoring and self-repairing integrated coating and the preparation method thereof provided by the invention, the real-time monitoring and repairing of the abnormal discharge condition of the cable are realized, and the service life of the cable is effectively prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable monitoring and self-repairing, and specifically relates to an integrated coating for cable abnormal discharge monitoring and self-repairing, and also relates to a preparation method of the integrated coating for cable abnormal discharge monitoring and self-repairing. Background Art

[0002] With the development of modern industry and life, cables are widely used in fields such as power transmission and communication, from urban power grids to industrial equipment and home appliance connections. However, since cables are usually buried underground, laid in pipelines or installed in hidden locations such as inside buildings, once a failure occurs, the cost of repair and replacement is high, and it may have a serious impact on production and life. Among them, during the operation of the cable, partial discharge may occur due to aging of the insulation material, manufacturing defects, overvoltage shocks, etc. Although the energy is small, long-term existence will damage the insulation performance of the cable and pose a serious safety hazard.

[0003] The applicant State Grid Corporation of China filed an invention patent with publication number CN 111426406A on June 2, 2020, disclosing a cable detection device and a detection method based on the temperature-sensitive color change of the cable coating. In this method, the cable coating has a solvent-free composite material with anti-corrosion, hydrophobic, insulating and color change indication functions, which is applied to the insulation layer of the main equipment cable of the distribution network. The new insulating material used can display different colors according to the temperature of the equipment, realizing visual monitoring of the equipment status. However, the detection of this method requires the use of large equipment, and cannot achieve early warning and timely repair to effectively avoid the spread of dangerous situations. The applicant Wuhan Fenghuo Ruituo Technology Co., Ltd. filed an invention patent with publication number CN118440237A on May 31, 2024, disclosing a self-healing polymer and its preparation method and application, self-healing coating, cable and communication equipment. The polymer prepared in this method is an acrylate polymer containing a diketone group, which causes the covalent bond of the diketone group to break at 70-80°C, and the self-healing polymer becomes soft and fills the damaged part; after cooling, the covalent bond is restored, and the self-healing polymer hardens to repair the damaged optical fiber. However, this method requires an external heating device to increase the temperature to trigger the repair, but this not only increases the complexity and cost of the repair, but may also have adverse effects on other equipment or the environment around the cable.

[0004] In summary, although these methods can detect and repair partial discharge to a certain extent, they still cannot achieve real-time monitoring and timely repair, increasing the risk and loss of cable failures. Summary of the invention

[0005] The first purpose of the present invention is to provide an integrated coating for cable abnormal discharge monitoring and self-repairing, so as to realize real-time monitoring and repair of abnormal discharge of cables and effectively improve the service life of cables.

[0006] The second object of the present invention is to provide a method for preparing an integrated coating for cable abnormal discharge monitoring and self-repairing.

[0007] The first technical solution adopted by the present invention is a method for preparing an integrated coating for cable abnormal discharge monitoring and self-repairing, which is specifically implemented according to the following steps:

[0008] Step 1, preparing microcapsules carrying repairing agent;

[0009] Step 2, preparing an outer coating layer solution, adding the repair agent-carrying microcapsules into the outer coating layer solution, and obtaining the repair agent-carrying microcapsules coated with the piezoelectric-based material;

[0010] Step 3, washing the repair agent-carrying microcapsules coated with the piezoelectric-based material in deionized water at a temperature of 30 to 80° C. for 2 to 8 hours to remove the pore-forming agent, and then freeze-drying the microcapsules to obtain porous piezoelectric-based material-coated repair agent-carrying microcapsules;

[0011] Step 4, mixing the repair agent-carrying microcapsules coated with the porous piezoelectric-based material obtained in step 3 with the coating carrier, dispersant, curing agent and catalyst according to a set ratio to obtain a coating.

[0012] The first technical solution of the present invention is also characterized in that:

[0013] Step 1 is as follows:

[0014] The core material repair agent and the emulsifier are mixed in cyclohexane to form an oil phase, and the shell material monomer is dissolved in deionized water to form a water phase. Through interfacial polymerization, at a temperature of 40 to 70°C and a stirring speed of 500 to 2000 rpm, after stirring for 1 to 5 hours, centrifugal washing and freeze-drying treatment are performed to obtain microcapsules loaded with the repair agent.

[0015] The mass fractions of the core material repair agent, emulsifier and shell material monomer are respectively: 10-60% of the core material repair agent, 1-10% of the emulsifier and 30-89% of the shell material monomer, and the total of the above mass fractions is 100%.

[0016] The core material repair agent is any one of epoxy resin, bisphenol A epoxy resin, silicone rubber or polyurea; the shell material monomer is any one of urea-formaldehyde resin, melamine resin or gelatin-arabic gum; and the emulsifier is Span-80 or Tween-80.

[0017] Step 2 is as follows:

[0018] 1-20% by mass of piezoelectric material and 1-6% by mass of pore-forming agent are dispersed in a mixed solution of N,N-methylenebisacrylamide DMF and acetone in a volume ratio of 5-8:2-5, and stirred in a water bath at 40-70°C for 1-5 hours to obtain an outer coating layer solution. The repair microcapsules obtained in step 1 are added to the outer coating layer solution, and after immersion for 6-24 hours, piezoelectric-based material-coated repair agent microcapsules are obtained.

[0019] The piezoelectric material is any one of polyvinylidene fluoride PVDF, polyvinylidene fluoride-trifluoroethylene or polyvinylidene fluoride-hexafluoropropylene;

[0020] The pore-forming agent is any one of sodium chloride, polyethylene oxide or sucrose.

[0021] Step 4 is as follows:

[0022] The porous piezoelectric-based material-coated repair agent microcapsules obtained in step 3 are mixed with a coating carrier, a dispersant, a curing agent and a catalyst in a set ratio, and stirred at a high speed of 1000 to 5000 rpm for 10 to 120 minutes to uniformly disperse the components to obtain a coating.

[0023] The mass fraction of the repair agent microcapsules coated with the porous piezoelectric base material is 10-50%, the mass fraction of the coating carrier material is 30-75%, the mass fraction of the dispersant is 1-5%, the mass fraction of the curing agent is 5-30% and the mass fraction of the catalyst is 0.1-2%, and the total mass fraction of the above components is 100%.

[0024] The coating carrier material is any one of epoxy resin, polyurethane or acrylic resin; the dispersant is any one of sodium dodecyl sulfate, sodium polyacrylate or sodium polycarboxylate; the curing agent is any one of ethylenediamine, diethylenetriamine or phthalic anhydride; and the catalyst is any one of triethylamine, dibutyltin dilaurate or tetrabutyl titanate.

[0025] The second technical solution adopted by the present invention is to use an integrated coating for cable abnormal discharge monitoring and self-repairing, which is prepared by using a preparation method for an integrated coating for cable abnormal discharge monitoring and self-repairing.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides an integrated coating for cable abnormal discharge monitoring and self-repairing and a preparation method thereof, which drives the piezoelectric material to form a piezoelectric effect through the tiny vibration formed by the abnormal discharge of the cable, and performs real-time monitoring and timely repair of the abnormal discharge of the cable. During the operation of the cable, once a partial discharge phenomenon occurs, the material can promptly and keenly discover the problem in the early stage, and win extremely valuable time for relevant personnel to take effective maintenance measures, thereby effectively avoiding the situation where the cable insulation damage caused by the further development of the discharge continues to increase, and greatly reducing the risk of safety accidents caused by cable failures. In addition, when the cable is unfortunately damaged by partial discharge, the piezoelectric-based microcapsules loaded with the repair material can respond to external stimuli at an extremely fast speed to release the repair material, and repair the cable in a timely and effective manner. In this way, the insulation performance of the cable can be quickly restored, effectively preventing a series of extremely dangerous safety accidents such as electric shock and fire that may be caused by insulation damage, greatly improving the safety of the cable during use, and providing a solid guarantee for the stable operation of the cable and the safety of people's lives and property. Therefore, by regulating the material composition and molecular level, the goal of integrating real-time monitoring and timely repair of abnormal cable discharge phenomena is achieved. The production cost is low and there are no special requirements for production equipment. It has good application prospects in the field of power cable repair materials. DETAILED DESCRIPTION

[0028] The present invention is described in detail below through specific implementation modes.

[0029] The present invention provides a method for preparing a coating for abnormal discharge monitoring and self-repairing of cables, which is specifically implemented according to the following steps:

[0030] Step 1, preparing microcapsules carrying repairing agent;

[0031] Step 1 is as follows:

[0032] The core material repair agent and the emulsifier are mixed in cyclohexane to form an oil phase, and the shell material monomer is dissolved in deionized water to form a water phase. Through interfacial polymerization, at a temperature of 40 to 70°C and a stirring speed of 500 to 2000 rpm, after stirring for 1 to 5 hours, centrifugal washing and freeze-drying treatment are performed to obtain microcapsules loaded with the repair agent.

[0033] Among them, the mass fractions of the core material repair agent, emulsifier and shell material monomer are respectively: core material repair agent 10-60%, emulsifier 1-10% and shell material monomer 30-89%, and the total of the above mass fractions is 100%.

[0034] The core material repair agent is any one of epoxy resin, bisphenol A epoxy resin, silicone rubber or polyurea; the shell material monomer is any one of urea-formaldehyde resin, melamine resin or gelatin-arabic gum; and the emulsifier is Span-80 or Tween-80.

[0035] Step 2, preparing an outer coating layer solution, adding the repair agent-carrying microcapsules into the outer coating layer solution to obtain the repair agent-carrying microcapsules coated with the piezoelectric-based material;

[0036] Step 2 is as follows:

[0037] 1-20% by mass of piezoelectric material and 1-6% by mass of pore-forming agent are dispersed in a mixed solution of N,N-methylenebisacrylamide DMF and acetone in a volume ratio of 5-8:2-5, and stirred in a water bath at 40-70°C for 1-5 hours to obtain an outer coating layer solution, and the repair microcapsules obtained in step 1 are added to the outer coating layer solution, and after immersion for 6-24 hours, piezoelectric-based material-coated repair agent microcapsules are obtained.

[0038] Wherein, the piezoelectric material is any one of polyvinylidene fluoride PVDF, polyvinylidene fluoride-trifluoroethylene or polyvinylidene fluoride-hexafluoropropylene; and the pore-forming agent is any one of sodium chloride, polyethylene oxide or sucrose.

[0039] Step 3, washing the piezoelectric-based material-coated repair agent-carrying microcapsules in deionized water at a temperature of 30 to 80° C. for 2 to 8 hours to remove the pore-forming agent, and then freeze-drying to obtain porous piezoelectric-based material-coated repair agent-carrying microcapsules;

[0040] Step 4, mixing the repair agent-carrying microcapsules coated with the porous piezoelectric-based material obtained in step 3 with the coating carrier, dispersant, curing agent and catalyst according to a set ratio to obtain a coating.

[0041] Step 4 is as follows:

[0042] The porous piezoelectric-based material-coated repair agent microcapsules obtained in step 3 are mixed with a coating carrier, a dispersant, a curing agent and a catalyst in a set ratio, and stirred at a high speed of 1000 to 5000 rpm for 10 to 120 minutes to uniformly disperse the components to obtain a coating.

[0043] The mass fraction of the repair agent microcapsules coated with the porous piezoelectric base material is 10-50%, the mass fraction of the coating carrier material is 30-75%, the mass fraction of the dispersant is 1-5%, the mass fraction of the curing agent is 5-30% and the mass fraction of the catalyst is 0.1-2%, and the total mass fraction of the above components is 100%.

[0044] The coating carrier material is any one of epoxy resin, polyurethane or acrylic resin; the dispersant is any one of sodium dodecyl sulfate, sodium polyacrylate or sodium polycarboxylate; the curing agent is any one of ethylenediamine, diethylenetriamine or phthalic anhydride; and the catalyst is any one of triethylamine, dibutyltin dilaurate or tetrabutyl titanate.

[0045] The present invention also provides a cable partial abnormal discharge repair coating, which is prepared by the above-mentioned preparation method.

[0046] Example 1

[0047] This embodiment provides a cable partial abnormal discharge repair coating and a preparation method thereof, and the specific steps are as follows:

[0048] Step 1, 10% epoxy resin and 1% Span-80 are mixed in cyclohexane to form an oil phase, 30% melamine resin is dissolved in deionized water to form a water phase, and the mixture is stirred at 40° C. and 500 rpm for 1 hour by interfacial polymerization, followed by centrifugal washing and freeze drying to obtain repair agent-loaded microcapsules;

[0049] Step 2, preparing an outer coating layer solution, adding the repair agent-carrying microcapsules into the outer coating layer solution, and obtaining the repair agent-carrying microcapsules coated with the piezoelectric-based material;

[0050] Disperse 1% polyvinylidene fluoride and 1% sodium chloride by mass in a mixed solution of N,N-methylenebisacrylamide (DMF) and acetone in a volume ratio of 7:3, heat and stir in a water bath at 40°C for 31 hours to obtain an outer coating solution, add the repairing microcapsules obtained in step 1 to the outer coating solution, and immerse for 6 hours to obtain repairing agent-loaded microcapsules coated with piezoelectric-based materials;

[0051] Step 3, washing the piezoelectric-based material-coated repair agent-loaded microcapsules obtained in step 2 in 50° C. deionized water for 2 hours to remove the pore-forming agent, and then freeze-drying the microcapsules to obtain porous piezoelectric-based material-coated repair agent-loaded microcapsules.

[0052] Step 4, the repair agent-carrying microcapsules coated with 10% porous piezoelectric-based material, 30% polyurethane, 1% sodium dodecyl sulfate, 5% ethylenediamine and 0.1% dibutyltin dilaurate obtained in step 3 are stirred at a high speed of 1000 rpm and a stirring time of 10 minutes to uniformly disperse the components to obtain an integrated coating for cable abnormal discharge monitoring and self-repairing.

[0053] Example 2

[0054] This embodiment provides a cable partial abnormal discharge repair coating and a preparation method thereof, and the specific steps are as follows:

[0055] Step 1, mixing 30% by mass of bisphenol A epoxy resin and 5% of Tween-80 in cyclohexane to form an oil phase, dissolving 60% of gelatin-gum arabic in deionized water to form a water phase, and performing interfacial polymerization at a temperature of 55° C. and a stirring speed of 1000 rpm for 3 hours, followed by centrifugal washing and freeze-drying to obtain repair agent-loaded microcapsules;

[0056] Step 2, preparing an outer coating layer solution, adding the repair agent-carrying microcapsules into the outer coating layer solution, and obtaining the repair agent-carrying microcapsules coated with the piezoelectric-based material;

[0057] Disperse 10% polyvinylidene fluoride-trifluoroethylene and 3% polyethylene oxide in a mixed solution of N,N-methylenebisacrylamide and acetone in a volume ratio of 7:4, heat and stir in a 50°C water bath for 3 hours to obtain an outer coating solution, add the repair microcapsules obtained in step 1 to the outer coating solution, and immerse for 12 hours to obtain piezoelectric-based material-coated repair agent microcapsules;

[0058] Step 3, washing the piezoelectric-based material-coated repair agent-loaded microcapsules obtained in step 2 in 50° C. deionized water for 3 hours to remove the pore-forming agent, and then freeze-drying to obtain porous piezoelectric-based material-coated repair agent-loaded microcapsules.

[0059] Step 4, the repair agent-carrying microcapsules coated with 30% porous piezoelectric-based material obtained in step 3, 55% acrylic resin, 3% sodium polyacrylate, 18% diethylenetriamine and 1% triethylamine are stirred at a high speed of 2500 rpm and a stirring time of 60 min to uniformly disperse the components to obtain an integrated coating for cable abnormal discharge monitoring and self-repairing.

[0060] Example 3

[0061] This embodiment provides a cable partial abnormal discharge repair coating and a preparation method thereof, and the specific steps are as follows:

[0062] Step 1, 60% silicone rubber and 10% Tween-80 are mixed in cyclohexane to form an oil phase, 89% urea-formaldehyde resin is dissolved in deionized water to form a water phase, and the mixture is stirred at 70°C and 2000 rpm for 5 hours by interfacial polymerization, followed by centrifugal washing and freeze drying to obtain repair agent-loaded microcapsules;

[0063] Step 2, preparing an outer coating layer solution, adding the repair agent-carrying microcapsules into the outer coating layer solution, and obtaining the repair agent-carrying microcapsules coated with the piezoelectric-based material;

[0064] Disperse 20% polyvinylidene fluoride-hexafluoropropylene and 6% sucrose in a mixed solution of N,N-methylenebisacrylamide and acetone in a volume ratio of 8:5, and heat and stir in a water bath at 70°C for 5 hours to obtain an outer coating solution. Add the repairing microcapsules obtained in step 1 to the outer coating solution, and immerse for 24 hours to obtain the repairing agent-loaded microcapsules coated with piezoelectric-based materials;

[0065] Step 3, washing the piezoelectric-based material-coated repair agent-loaded microcapsules obtained in step 2 in 50° C. deionized water for 2 hours to remove the pore-forming agent, and then freeze-drying the microcapsules to obtain porous piezoelectric-based material-coated repair agent-loaded microcapsules.

[0066] Step 4, the repair agent-carrying microcapsules coated with 50% porous piezoelectric-based material, 75% polyurethane, 5% sodium polycarboxylate, 30% phthalic anhydride and 2% triethylamine obtained in step 3 are stirred at a high speed of 5000 rpm and a stirring time of 120 min to uniformly disperse the components to obtain an integrated coating for cable abnormal discharge monitoring and self-repairing.

[0067] Example 4

[0068] This embodiment provides a cable partial abnormal discharge repair coating and a preparation method thereof, and the specific steps are as follows:

[0069] Step 1, 50% by mass of bisphenol A epoxy resin and 5% of Span-80 are mixed in cyclohexane to form an oil phase, 45% of gelatin-gum arabic is dissolved in deionized water to form a water phase, and the mixture is stirred at 60° C. and 1500 rpm for 4 hours by interfacial polymerization, followed by centrifugal washing and freeze drying to obtain repair agent-loaded microcapsules;

[0070] Step 2, 10% polyvinylidene fluoride-trifluoroethylene and 3% polyethylene oxide (dispersed in a mixed solution of N,N-methylenebisacrylamide and acetone in a volume ratio of 6:4, heated in a water bath at 60°C and stirred for 3 hours to obtain an outer coating solution, and the repair microcapsules obtained in step 1 were added to the outer coating solution, and after immersion for 12 hours, piezoelectric-based material-coated repair agent microcapsules were obtained;

[0071] Step 3, washing the piezoelectric-based material-coated repair agent-loaded microcapsules obtained in step 2 in deionized water at 60° C. for 6 hours to remove the pore-forming agent, and then freeze-drying the microcapsules to obtain porous piezoelectric-based material-coated repair agent-loaded microcapsules.

[0072] Step 4, the repair agent-carrying microcapsules coated with 25% porous piezoelectric-based material obtained in step 3, 58% polyurethane, 1% sodium dodecyl sulfate, 15% diethylenetriamine and 1% dibutyltin dilaurate are stirred at a high speed of 4000 rpm and a stirring time of 120 min to uniformly disperse the components to obtain an integrated coating for cable local abnormal discharge monitoring and self-repairing.

Claims

1. A method for preparing an integrated coating for cable abnormal discharge monitoring and self-repairing, characterized in that: Follow the steps below to implement it: Step 1, preparing microcapsules carrying repairing agent; Step 2, preparing an outer coating layer solution, adding the repair agent-carrying microcapsules into the outer coating layer solution to obtain the repair agent-carrying microcapsules coated with the piezoelectric-based material; Step 3, washing the piezoelectric-based material-coated repair agent-carrying microcapsules in deionized water at a temperature of 30 to 80° C. for 2 to 8 hours to remove the pore-forming agent, and then freeze-drying to obtain porous piezoelectric-based material-coated repair agent-carrying microcapsules; Step 4, mixing the repair agent-carrying microcapsules coated with the porous piezoelectric-based material obtained in step 3 with the coating carrier, dispersant, curing agent and catalyst according to a set ratio to obtain a coating.

2. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 1, characterized in that: The step 1 is specifically as follows: The core material repair agent and the emulsifier are mixed in cyclohexane to form an oil phase, and the shell material monomer is dissolved in deionized water to form a water phase. Through interfacial polymerization, at a temperature of 40 to 70°C and a stirring speed of 500 to 2000 rpm, after stirring for 1 to 5 hours, centrifugal washing and freeze-drying treatment are performed to obtain microcapsules loaded with the repair agent.

3. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 2, characterized in that: The mass fractions of the core material repair agent, emulsifier and shell material monomer are: 10-60% of the core material repair agent, 1-10% of the emulsifier and 30-89% of the shell material monomer, and the total of the above mass fractions is 100%.

4. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 3, characterized in that: The core material repair agent is any one of epoxy resin, bisphenol A epoxy resin, silicone rubber or polyurea; the shell material monomer is any one of urea-formaldehyde resin, melamine resin or gelatin-arabic gum; and the emulsifier is Span-80 or Tween-80.

5. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 1, characterized in that: The step 2 is specifically as follows: 1-20% by mass of piezoelectric material and 1-6% by mass of pore-forming agent are dispersed in a mixed solution of N,N-methylenebisacrylamide DMF and acetone in a volume ratio of 5-8:2-5, and stirred in a water bath at 40-70°C for 1-5 hours to obtain an outer coating layer solution, and the repair microcapsules obtained in step 1 are added to the outer coating layer solution, and after immersion for 6-24 hours, piezoelectric-based material-coated repair agent microcapsules are obtained.

6. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 5, characterized in that: The piezoelectric material is any one of polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene or polyvinylidene fluoride-hexafluoropropylene; The pore-forming agent is any one of sodium chloride, polyethylene oxide or sucrose.

7. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 1, characterized in that: The step 4 is specifically as follows: The porous piezoelectric-based material-coated repair agent microcapsules obtained in step 3 are mixed with a coating carrier, a dispersant, a curing agent and a catalyst in a set ratio, and stirred at a high speed of 1000 to 5000 rpm for 10 to 120 minutes to uniformly disperse the components to obtain a coating.

8. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 7, characterized in that: The mass fraction of the repair agent microcapsules coated with the porous piezoelectric-based material is 10-50%, the mass fraction of the coating carrier material is 30-75%, the mass fraction of the dispersant is 1-5%, the mass fraction of the curing agent is 5-30% and the mass fraction of the catalyst is 0.1-2%, and the total mass fraction of the above components is 100%.

9. The method for preparing the integrated coating for cable abnormal discharge monitoring and self-repairing according to claim 8, characterized in that: The coating carrier material is any one of epoxy resin, polyurethane or acrylic resin; the dispersant is any one of sodium dodecyl sulfate, sodium polyacrylate or sodium polycarboxylate; the curing agent is any one of ethylenediamine, diethylenetriamine or phthalic anhydride; the catalyst is any one of triethylamine, dibutyltin dilaurate or tetrabutyl titanate.

10. Used for cable abnormal discharge monitoring and self-repairing integrated coating, characterized in that: The coating is prepared by the method for preparing an integrated coating for abnormal discharge monitoring and self-repairing of cables according to any one of claims 1 to 9.