Method for Quality Inspection of Joining of Power Cables

Abstract

A method for performing quality inspection of a vulcanized joint during the manufacture of a power cable vulcanized joint, the method comprising: a) obtaining from a laser scanner measurement values of the outer surface of the inner semiconductor layer provided on the conductor joint joining the conductors of two power cable sections, and measurement values of the transition area between the outer surface and the outer surface of each inner semiconductor layer of the two power cable sections; b) obtaining from the laser scanner measurement values of the outer surface of the tapered section of the insulation layer disposed around each one of the inner semiconductor layers of the two cable sections; c) processing the measurement values obtained in step a) and step b), wherein processing involves generating a 3D model of one or each of the outer surfaces and evaluating the outer surface quality of the outer surface based on the one or more 3D models, processing the measurement values obtained in step a) and step b); d) presenting a conclusion regarding the surface quality based on the evaluation; e) obtaining from the laser scanner measurement values of the outer surface of the joint insulation disposed around the inner semiconductor layer provided on the conductor joint, wherein the joint insulation is provided on the inner semiconductor layer provided around the conductor joint after step d), obtaining the measurement values of the outer surface of the joint insulation; f) processing the measurement values obtained from the laser scanner in step e), wherein processing involves determining the insulation thickness or outer diameter of the joint insulation, processing the measurement values obtained from the laser scanner; g1) presenting the insulation thickness or outer diameter; and / or g2) evaluating the insulation thickness or outer diameter and presenting a conclusion regarding the insulation thickness or outer diameter based on a comparison.

Description

Technical Field

[0001] The present disclosure generally relates to power cables.

Background Art

[0002] High voltage (HV) power cables generally include, from the inside out, a conductor, an insulation system, and an outer sheath. In particular, the insulation system comprises an inner semiconductor layer, an insulating layer disposed around the inner semiconductor layer, and an outer semiconductor layer disposed around the insulating layer.

[0003] For example, when making a splice, it is necessary to mechanically process the HV power cable. Processing includes stripping the outer semiconductor layer and may include subsequent grinding of the insulating layer, depending on the voltage rating of the cable.

[0004] It is important that the processed layer has a uniform surface structure. Conventional methods of inspecting the processing results rely on manual inspection of the processed layer by sliding a finger over the processed area for tactile feedback. The quality of the manual inspection depends on the experience of the person performing the inspection.

[0005] Other conventional methods include measurements using a slide gauge or a diameter tape. Generally, conventional methods of inspecting the insulation of HV cables after processing have limitations regarding their reliability and repeatability.

[0006] EP3 901 571A1 discloses a system and method for determining the quality of the surface of a high voltage cable end. The method includes moving a non-contact surface scanner around the cable end, measuring the distance to the surface across the surface area by continuously measuring a plurality of sub-areas of the surface area, creating a continuous 3D surface geometry measurement of the cable end, and comparing the continuous 3D surface geometry measurement with at least one surface geometry acceptance threshold for determining the quality of the surface of the high voltage cable end.

Summary of the Invention

[0007] The object of the present disclosure is to provide a method for performing a quality inspection of a power cable that solves or at least alleviates the problems of the prior art.

[0008] Thus, according to a first aspect of the present disclosure, there is provided a method for performing a quality inspection of a vulcanized joint during the manufacture of a vulcanized joint of a power cable, the method comprising: a) obtaining from a laser scanner measurements of the outer surface of the inner semiconductor layer provided on the conductor joint joining the conductors of two power cable sections, and measurements of the transition area between the outer surface and the outer surface of the inner semiconductor layer of each of the two power cable sections; b) obtaining from the laser scanner measurements of the outer surface of the tapered section of the insulation layer disposed around each one of the inner semiconductor layers of the two cable sections; c) processing the measurements obtained in step a) and step b), the processing involving generating a 3D model of one or each of the outer surfaces and evaluating the outer surface quality of the outer surface based on the one or more 3D models; d) presenting a conclusion regarding the surface quality based on the evaluation; e) obtaining from the laser scanner measurements of the outer surface of the joint insulation disposed around the inner semiconductor layer provided on the conductor joint, the joint insulation being provided on the inner semiconductor layer provided around the conductor joint after step d); f) processing the measurements obtained from the laser scanner in step e), the processing involving determining the insulation thickness or outer diameter of the joint insulation; g1) presenting the insulation thickness or outer diameter; and / or g2) evaluating the insulation thickness or outer diameter and presenting a conclusion regarding the insulation thickness or outer diameter based on the comparison.

[0009] Therefore, the quality of all processed layers of the vulcanized joint can be determined using an automated process that does not depend on the experience of the personnel performing the joining. Thus, a vulcanized joint of the required quality can be constructed without relying heavily on human experience.

[0010] Processing in step c) may involve determining the angle or slope of the tapered section. Step d) may, in this case, involve presenting the angle or slope of the tapered section. Having the correct angle / slope of the tapered section, or cone, is important when making the joint.

[0011] According to one embodiment, step f) involves generating a 3D model of the outer surface of the joint insulation.

[0012] According to one embodiment, evaluating in step c) involves assessing the roundness and surface texture of the outer surface.

[0013] According to one embodiment, evaluating in step c) involves comparing each 3D model with its respective reference 3D model.

[0014] According to one embodiment, evaluating in step g2) involves comparing the insulation thickness or outer diameter with a reference.

[0015] According to one embodiment, the reference is a 3D model of the joint insulation.

[0016] According to one embodiment, the laser scanner is a 3D laser scanner.

[0017] According to a second aspect of the present disclosure, there is provided a quality inspection system comprising a processing circuit, a laser scanner configured to send measurement values to the processing circuit, and a storage medium comprising computer code that, when executed by the processing circuit, causes the quality inspection system to perform the method according to the first aspect.

[0018] According to a third aspect of the present disclosure, a method for vulcanizing and joining a power cable using the quality inspection system described in the second aspect, the method comprising: A) performing a conductor joint between two conductor ends of each power cable length to form a single power cable from two separated power cable sections by conductor joint; B) tapering each insulating layer of the two power cable sections; C) providing an inner semiconductor layer around the conductor joint, the inner semiconductor layer contacting the inner semiconductor layer of each power cable section; D) using the quality inspection system to perform a quality inspection on the outer surface of the inner semiconductor layer and the tapered outer surfaces of the insulating layers of the two power cable sections, and if the result of the quality inspection is non-conforming, the method comprising: E) mechanically treating the outer surface(s) of the inner semiconductor layer(s) and / or the tapered outer surface, and repeating step D); and if the result of the quality inspection is conforming, the method comprising: F) performing joint insulation on the inner semiconductor layer provided around the conductor joint, the joint insulation contacting the tapered outer surface, and performing a quality inspection on the outer surface of the inner semiconductor layer and the tapered outer surfaces of the insulating layers of the two power cable sections; G) using the quality inspection system to perform a quality inspection on the joint insulation to determine the outer diameter or insulation thickness of the joint insulation, and if the result of the quality inspection in step G is non-conforming, the method comprising: H) mechanically treating the outer surface of the joint insulation, and repeating steps G and H until the result of the quality inspection in step G becomes conforming, and a method is provided that includes performing a quality inspection on the joint insulation.

[0019] Generally, all terms used in the claims should be construed in accordance with their ordinary meaning in the art, unless explicitly defined otherwise herein. All references to "an / a / the element, apparatus, component, means", etc. should be construed broadly to refer to at least one instance of the element, apparatus, component, means, etc., unless otherwise explicitly stated.

[0020] Next, by way of example, specific embodiments of the concepts of the present invention will be described with reference to the accompanying drawings.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0022] Next, the concepts of the present invention will be described in more detail below with reference to the accompanying drawings showing the exemplary embodiments. However, the concepts of the present invention can be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will fully convey the scope of the concepts of the present invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0023] FIG. 1 shows a block diagram of an example of a quality inspection system 1. The quality inspection system 1 is configured to provide quality inspection of an insulation system layer of a vulcanized joint of a power cable during the manufacturing process of the vulcanized joint.

[0024] The power cable can be an underground power cable or a submarine power cable. The power cable can be an AC or DC power cable. The power cable can be a medium-voltage or high-voltage power cable.

[0025] The quality inspection system 1 includes a laser scanner 3. The laser scanner can be a 3D laser scanner. The laser scanner 3 can be handheld. Thus, a user can hold the laser scanner 3 in the user's hand when scanning an object such as a vulcanized joint. Alternatively, the laser scanner 3 can be attached to a structure that enables axial movement along the power cable and / or circumferential movement in the circumferential direction around the power cable.

[0026] The quality inspection system 1 includes a processing circuit 5 connected to the laser scanner 3. Further, the quality inspection system 1 can include a storage medium 7 configured to communicate with the processing circuit 5.

[0027] The processing circuit 5 and / or the storage medium 7 can be integrated with the laser scanner 3, or one or both of the processing circuit 5 and the storage medium 7 can be configured separately from the laser scanner 3.

[0028] The processing circuit 5 can use, for example, one or any combination of suitable central processing units (CPUs), multiprocessors, microcontrollers, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc. that are capable of performing the operations disclosed in this specification regarding quality inspection of a vulcanized joint of a power cable.

[0029] The memory medium 7 can be embodied as a non-volatile memory medium of a device in an external memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM), more specifically, a USB (Universal Serial Bus) memory, or a flash memory such as a compact flash memory.

[0030] Next, a method of performing the vulcanization joint 10 shown in FIG. 3 will be described with reference to FIGS. 2 to 4. Performing the vulcanization joint 10 generally involves manual steps performed by factory personnel in a cable factory or, for example, by on-site personnel on a cable laying ship, and a quality inspection performed during the vulcanization joint 10 involves the use of a quality inspection system 1 operated by, for example, factory / on-site personnel.

[0031] FIG. 2 schematically shows a process of performing a vulcanization joint using the quality inspection system 1. The vulcanization joint is a flexible joint that is usually performed in a factory but can also be performed on-site, for example, on a cable laying ship. The vulcanization joint 10 joins two power cable sections, which thus form a single power cable. The power cable sections each include respective conductors 11a, 11b that are joined by a conductor joint 11c. Further, each power cable length includes respective insulation systems 13, 15. Each insulation system 13, 15 includes an inner semiconductor layer 13a, 15a disposed around the respective conductors 11a, 11b, an insulation layer 13b, 15b disposed around the inner semiconductor layers 13a, 15a, and an outer semiconductor layer 13c, 15c disposed around the insulation layers 13b, 15b.

[0032] The inner semiconductor layers 13a, 15a can include, for example, cross-linked polyethylene (XLPE). The insulation layers 13b, 15b can include XLPE. The outer semiconductor layers 13c, 15c can include XLPE.

[0033] Before joining, the cable ends of the two power cable lengths are processed by removing the insulation systems 13, 15 to expose the conductors 11a and 11b. The conductors 11a and 11b are then joined in step A) shown in FIG. 4 to form the conductor joint 11c shown in FIG. 2. The joining is performed by welding, for example, to perform a V-shaped weld.

[0034] In step B), the two opposing ends of each of the insulation layers 13b and 15b are tapered so that they taper towards each other. The opposing ends of the insulation layers 13b and 15b are tapered by mechanical processing.

[0035] In step C), the inner semiconductor layer 17 is disposed on the conductor joint 11c and over the entire exposed section of the conductors 11a and 11b after their joining. The inner semiconductor layer 17 is disposed so as to overlap the two inner semiconductor layers 13a and 15a of the two joined power cable lengths, which now become the power cable section of the joined power cable. The overlapping region between the inner semiconductor layer 17 and the two inner semiconductor layers 13a and 15a is the transition area of the common inner semiconductor layer of the power cable formed by the two joined power cable lengths.

[0036] The inner semiconductor layer 17 can be produced, for example, by winding a layer of tape around the conductor joint 11c and the exposed sections of the conductors 11a and 11b and heating the layer of tape to crosslink the inner semiconductor layer 17, or the inner semiconductor layer 17 can be produced by injection molding followed by further heating.

[0037] In step D), a quality inspection of the outer surfaces of the inner semiconductor layers 17, 13a, 15a is performed using the quality inspection system 1. For example, a laser scanner 3 held by factory or field personnel is moved over the outer surface of the inner semiconductor layer 17 and the transition area to scan the outer surface of the inner semiconductor layer 17 and the transition area.

[0038] During step D), in step a), the measured values of the outer surface of the inner semiconductor layer 17 and the transition area are acquired by the processing circuit 5.

[0039] Furthermore, in step D), the laser scanner 3 is moved over each tapered section of the insulating layers 13b and 15b and scans the outer surface of the tapered section.

[0040] In step b), the processing circuit 5 acquires the measured values of the outer surface of the tapered section from the laser scanner 3.

[0041] In step c), the measured values obtained in step a) and step b) are processed by the processing circuit 5.

[0042] The processing involves generating a single or respective 3D model of the outer surface and evaluating the outer surface quality of the outer surface based on one or more 3D models. Thus, according to one example, the measured values from each external surface area can each be used to generate a respective 3D model that models, for example, each transition area and the outer surface of the inner semiconductor layer 17 between the transition areas, or a single 3D model can be generated that models all the scanned outer surfaces.

[0043] Evaluating in step c) can involve comparing each 3D model with a respective reference 3D model and determining whether the surface quality meets or fails a predefined criterion. Evaluating in step c) can involve, for example, assessing the roundness of the outer surface, measured along the outer perimeter of the outer surface, and / or assessing the surface texture, such as smoothness and irregularities, of the outer surface. The roundness and surface texture can be evaluated, for example, by comparing the determined parameters with respective acceptable thresholds or by the degree of deviation from the reference 3D model(s).

[0044] In step d), a conclusion regarding the surface quality based on the evaluation is presented by the quality inspection system 1. The presentation can be, for example, visual on a display and / or, for example, auditory by emitting a predefined sound if the surface quality meets a predefined standard or fails to meet a predefined standard.

[0045] If the result of the quality inspection of the outer surface in steps c) to d) is unqualified, the method of performing vulcanization bonding includes: step E) mechanically processing the outer surface(s) of the inner semiconductor layer(s), the transition area, and / or the tapered outer surface; and repeating the quality inspection of these outer surfaces after the mechanical processing.

[0046] When the result of the quality inspection is qualified, the method of performing vulcanization bonding includes step F) performing bonding insulation 19 on the inner semiconductor layer 17 provided around the conductor bonding 11c. The bonding insulation 19 extends between the tapered outer surfaces and contacts the tapered outer surfaces. The bonding insulation 19 can be performed, for example, by winding a layer of insulating tape around the inner semiconductor layer 17 and subjecting the insulating tape to a heat treatment for crosslinking, or the bonding insulation 19 can be performed by injection molding followed by a subsequent heat treatment.

[0047] After step F), step G) is performed to perform a quality inspection of the bonding insulation 19 using the quality inspection system 1 to determine, for example, by factory personnel or on-site personnel, the outer diameter or insulation thickness of the bonding insulation 19.

[0048] During step G), in step e), the measured value of the outer surface 19a of the bonding insulation 19 is obtained from the laser scanner 3 that scans the outer surface 19a of the bonding insulation 19.

[0049] In step f) performed by the quality inspection system 1, the measurement values obtained from the laser scanner 3 in step e) are processed by the processing circuit 5. Processing involves determining the insulation thickness or outer diameter of the joint insulation 19.

[0050] Furthermore, in step g1) performed by the quality inspection system 1, the insulation thickness or outer diameter of the joint insulation 19 is presented. The presentation can be on the display of the quality inspection system 1 and / or the presentation can be auditory. By the quality inspection system 1, in addition to or as an alternative to step g1), in step g2) which can be performed, the insulation thickness or outer diameter is evaluated and a conclusion regarding the insulation thickness or outer diameter based on a comparison is presented. The presentation can be on the display of the quality inspection system 1 and / or the presentation can be auditory.

[0051] Evaluating in step g2) can involve comparing the insulation thickness or outer diameter with a reference. The reference can be a 3D model of the joint insulation 19.

[0052] If the result of the quality inspection in step G) is non - compliant, the method includes: H) mechanically processing the outer surface 19a of the joint insulation 19 and repeating steps G) and H) until the result of the quality inspection in step G) is compliant.

[0053] The concept of the present invention has been described above mainly with reference to several examples. However, as will be immediately understood by those skilled in the art, other embodiments other than the embodiments disclosed above are equally possible within the scope of the concept of the present invention as defined by the appended claims.

Claims

1. A method for performing a quality inspection of a vulcanized joint (10) of a power cable during its manufacture, wherein the method is: a) Obtaining measurements from the laser scanner (3) of the outer surface of the inner semiconductor layer (17) provided on the conductor joint (11c) that joins the conductors (11a, 11b) of the two power cable sections, and measurements of the transition area between the outer surface and the outer surfaces of the respective inner semiconductor layers (13a, 15a) of the two power cable sections, b) Obtaining measurements from the laser scanner (3) of the outer surface of the tapered section of the insulating layer (13b, 15b) arranged around one of the inner semiconductor layers (13a, 15a) of the two cable sections, c) Processing the measurements obtained in step a) and step b), wherein the processing involves generating a 3D model of one or each of the outer surfaces and evaluating the outer surface quality of the outer surfaces based on the one or more 3D models, d) Present conclusions regarding surface quality based on the above evaluation, e) Obtaining a measurement of the outer surface of the junction insulation (19) arranged around the inner semiconductor layer (17) provided on the conductor junction (11c) from the laser scanner (3), wherein the junction insulation (19) is provided on the inner semiconductor layer (17) provided around the conductor junction (11c) after step d), f) Processing the measured values ​​obtained from the laser scanner (3) in step e), wherein the processing involves determining the insulation thickness or outer diameter of the joint insulation (19), g1) To provide the insulation thickness or the outer diameter, and / or g2) Evaluate the insulation thickness or the outer diameter, and present conclusions regarding the insulation thickness or the outer diameter based on the comparison. Methods that include...

2. The method according to claim 1, wherein step f) involves generating a 3D model of the outer surface of the joint insulation.

3. The method according to claim 1 or 2, wherein the evaluation in step c) involves assessing the roundness and surface texture of the outer surface.

4. The method according to claim 1 or 2, wherein the evaluation in step c) involves comparing each 3D model with its respective reference 3D model.

5. The method according to claim 1 or 2, wherein the evaluation in step g2) involves comparing the insulation thickness or the outer diameter with a reference.

6. The method according to claim 5, wherein the standard is a 3D model of the joint insulation.

7. The method according to claim 1 or 2, wherein the laser scanner (3) is a 3D laser scanner (3).

8. Quality inspection system (1), Processing circuit (5), A laser scanner (3) configured to send measurement values ​​to the processing circuit (5), A storage medium (7) comprising computer code that, when executed by the processing circuit (5), causes the quality inspection system (1) to perform the method according to claim 1 or 2, and A quality inspection system (1) equipped with the following features.

9. A method for performing vulcanization bonding (10) of a power cable using the quality inspection system (1) described in claim 8, wherein the method is: A) Conductor joints (11c) are made between the two conductor ends of each power cable length in order to form a single power cable from two separated power cable sections by the conductor joints (11c), B) The insulating layers (13b, 15b) of the two power cable sections are tapered, C) Providing an inner semiconductor layer (17) around the conductor joint (11c), wherein the inner semiconductor layer (17) is in contact with each of the inner semiconductor layers (13a, 15a) of the power cable section, D) Using the quality inspection system (1), perform quality inspection of the outer surface of the inner semiconductor layer (17) and the tapered outer surface of the insulating layers (13b, 15b) of the two power cable sections, If the result of the quality inspection is unsatisfactory, the method includes E) mechanically processing the outer surface(s) and / or tapered outer surface(s) of the inner semiconductor layer(s), and repeating step D), If the result of the quality inspection is satisfactory, the method includes F) performing joint insulation (19) on the inner semiconductor layer (17) provided around the conductor joint (11c), wherein the joint insulation (19) is in contact with the tapered outer surface. The quality inspection is performed on the outer surface of the inner semiconductor layer (17) and the tapered outer surface of the insulating layers (13b, 15b) of the two power cable sections. G) In order to determine the outer diameter or insulation thickness of the joint insulation (19), the quality inspection system (1) is used to perform a quality inspection of the joint insulation (19), If the result of the quality inspection in step G) is unsatisfactory, the method includes H) mechanically treating the outer surface of the joint insulation (19) and repeating steps G) and H) until the result of the quality inspection in step G) is satisfactory. The quality inspection of the aforementioned joint insulation (19) is performed. Methods that include...

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