Power Cable Insulation Jointing With Tapered Tape Edge Control
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Solution Overview
Problem
The existing insulation system of power cables, particularly in factory joints, faces issues with edge formation between semiconducting and insulating layers due to differential heating, leading to increased electric fields and potential insulation breakdown.
Innovation Solution
A method involving a tapering tape with decreasing thickness towards its edges, wound in overlapping layers and heated under pressure, to form a seamless insulation system without edge formation, ensuring a high filling factor and reduced risk of electric field increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform thickness tape is used during heating process, then the insulation layer forms properly, but edges form between insulation layer and semiconducting layers due to differential softening
Solution Approach 1:
The tape is designed with non-uniform thickness distribution, where the thickness varies along the width of the tape. Specifically, the tape is thickest at the center and gradually thinner toward the edges. This local variation in thickness compensates for the differential softening rates during heating, preventing edge formation between layers while maintaining proper insulation layer formation.
2Manufacturing precision
If tape thickness decreases towards lateral edges, then edge formation is reduced, but tape structural complexity increases
Solution Approach 1:
The tape's physical parameter (thickness) is changed systematically across its width. By controlling the thickness parameter to decrease from the center toward the lateral edges, the invention achieves better edge formation control during heating. This parameter variation is implemented in a controlled manner that does not significantly complicate the manufacturing process.
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
This approach effectively mitigates edge formation and electric field issues, enhancing the reliability and longevity of power cable insulation systems by ensuring a smooth thickness transition and high filling factor during the heating process.
Implementation Method 1
heating the plurality of layers of tape to melt and fuse the plurality of layers of tape to form an insulation system layer between the first insulation system section and the second insulation system section
Implementation Method 2
heating the plurality of layers of tape to melt and fuse the plurality of layers of tape
Data Source
AI summary
A method of building an insulation system around an axial section of a conductor of a power cable, the method including: a) providing a power cable including a conductor and an insulation system arranged around the conductor, the insulation system including insulation system layers, including an inner semiconducting layer arranged around the conductor, an insulation layer arranged around the inner semiconducting layer, and an outer semiconducting layer arranged around the insulation layer, wherein the power cable includes an axial section between a first insulation system section and a second insulation system section of the insulation system which at least is without an outer semiconducting layer, b) winding a tape around the conductor along the axial section in a plurality of layers to form a plurality of layers of tape connecting with the first insulation system section and the second insulation system section, and c) heating the plurality of layers of tape to melt and fuse the plurality of layers of tape to form an insulation system layer between the first insulation system section and the second insulation system section, wherein the tape has a width defined by a distance between lateral edges, wherein the tape has a mid-section between its lateral edges, wherein in the mid-section the tape has a largest thickness, and wherein the thickness of the tape decreases from the mid-section towards both lateral edges.