Power Cable Joint Inspection Using 3D Laser Surface Models
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Solution Overview
Problem
Conventional methods for inspecting the quality of processed layers in high voltage power cables rely heavily on human experience and are unreliable and non-replicable, lacking consistency in determining the quality of mechanical processing results.
Innovation Solution
An automated method using a laser scanner to generate 3D models of the outer surfaces of power cable layers, evaluating surface quality, and determining parameters like angle, slope, roundness, and surface texture, with comparisons to reference models, to ensure consistent and reliable quality inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual inspection by tactile feedback is used, then the inspection process is simple and quick, but the reliability and replicability of quality determination deteriorates due to dependence on inspector experience
Solution Approach 1:
The patent replaces the manual tactile inspection method with an automated optical measurement system using a laser scanner. The laser scanner captures 3D surface geometry data of the processed cable layers, eliminating the need for manual finger sliding and tactile assessment. This substitution transforms the inspection from a subjective mechanical process to an objective automated measurement process, thereby improving reliability and replicability while maintaining operational simplicity through automated data processing and comparison with reference models.
Solution Approach 2:
The patent creates a digital 3D copy (point cloud model) of the actual processed surface and compares it with a reference 3D model representing the ideal surface geometry. This copying approach allows for precise, repeatable quality assessment by digitally comparing the measured surface against acceptance criteria stored as reference models, eliminating dependence on human experience while maintaining easy operation through automated comparison algorithms.
2Device complexity
If conventional measurement methods like slide gauge or diameter tape are used, then the equipment is simple and easy to use, but the measurement precision and consistency of inspection results deteriorates
Solution Approach 1:
The patent transitions from conventional 2D linear measurements using slide gauges or diameter tapes to 3D surface geometry measurement using a laser scanner. The laser scanner captures spatial coordinates (x, y, z) of surface points, creating a comprehensive 3D point cloud model that fully characterizes the surface topology including roundness, flatness, and profile accuracy. This dimensional upgrade provides significantly higher measurement precision and consistency while the automated processing maintains ease of use.
3Reliability
If automated laser scanning is implemented, then the reliability and consistency of quality inspection improves, but the device complexity and measurement time increases
Solution Approach 1:
The patent implements an automated self-service inspection system where the laser scanner automatically captures surface data, processes the point cloud to generate 3D models, compares measurements with reference models, and determines compliance without requiring complex manual intervention. The system performs self-calibration and automated decision-making, reducing the need for complex operator training and intervention while maintaining high reliability and consistency in inspection results.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the construction of high-quality vulcanized joints by eliminating reliance on human experience, ensuring consistent and reliable inspection of inner semiconducting layers and insulation thickness, thereby improving the manufacturing process.
Implementation Method 1
a) obtaining, from a laser scanner, measurements of an outer surface of an inner semiconducting layer
Implementation Method 2
measuring distance to the surface over the area of the surface by sequentially measuring a plurality of sub-areas
Data Source
Figure 1~3
Figure 4
AI summary
A method of performing a quality inspection of a vulcanized joint of a power cable during manufacturing of the vulcanized joint, the method comprising: a) obtaining, from a laser scanner, measurements of an outer surface of an inner semiconducting layer provided over a conductor joint which joints conductors of two power cable sections, and of a transition area between the outer surface and outer surfaces of a respective inner semiconducting layer of the two power cable sections, b) obtaining, from a laser scanner, measurements of an outer surface of a tapering section of an insulation layer arranged around a respective one of the inner semiconducting layers of the two cable sections, c) processing the measurements obtained in step a) and in step b), the processing involving generating one or a respective 3-d model of the outer surfaces and evaluating an outer surface quality of the outer surfaces based on the one or more 3-d models, d) presenting a conclusion regarding surface quality based on the evaluation, e) obtaining, from a laser scanner, measurements of an outer surface of a joint insulation arranged around the inner semiconducting layer that is provided over the conductor joint, the joint insulation having been provided over the inner semiconducting layer provided around the conductor joint after step d), and f) processing measurements obtained from the laser scanner in step e), the processing involving determining an insulation thickness or an outer diameter of the joint insulation, and g1) presenting the insulation thickness or outer diameter, and/or, g2) evaluating the insulation thickness or outer diameter, and presenting a conclusion regarding the insultation thickness or outer diameter based on the comparison.