Woven High-Voltage Cable Layout for Skin Effect and Partial Discharge
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Solution Overview
Problem
Existing electrical cables face challenges in transmitting high-power, high-voltage electrical signals at kilohertz frequencies while maintaining lightweight design, resisting partial discharges, and minimizing resistive losses, especially in low-pressure environments such as high altitudes where air density is low.
Innovation Solution
A single-phase electrical cable design featuring a bundle of metallic wires separated by non-conductor layers, woven to alternate between outer and inner positions, surrounded by a broad-range temperature-rated polymeric semi-conductive and insulating layer, with selected metallic wires in electric contact with the semi-conductive layer to mitigate skin and proximity effects and prevent partial discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrical cables are used for high-power, high-voltage transmission at kilohertz frequencies, then power transmission capability is improved, but resistive losses and heat generation increase due to skin effect and proximity effect
Solution Approach 1:
The conductor is segmented into multiple individually insulated metallic wires instead of a single solid conductor. This segmentation reduces the skin effect and proximity effect by distributing current across multiple smaller conductors, thereby reducing resistive losses while maintaining high power transmission capability
Solution Approach 2:
The metallic wires are arranged in a flexible bundle configuration that allows dynamic positioning. The wires can be individually insulated and positioned to optimize current distribution and minimize electromagnetic interference, enabling efficient high-frequency power transmission
2Loss of energy
If litz wires with individually insulated conductors are used to reduce skin effect, then resistive losses are reduced, but risk of partial discharge increases in high-voltage applications especially at high altitude
Solution Approach 1:
The insulation characteristics are optimized locally at different positions within the cable structure. Individual metallic wires have insulation tailored to their specific voltage potential and position, with enhanced insulation at critical locations where partial discharge risk is highest, while maintaining thin insulation elsewhere to minimize overall cable diameter and weight
Solution Approach 2:
A semi-conductive layer is introduced as an intermediary between the individually insulated metallic wires and the outer insulation. This semi-conductive layer equalizes the electric field distribution and prevents voltage differences that could lead to partial discharge, while allowing the individual wire insulation to remain thin for reduced resistive losses
3Weight of moving object
If cable weight is reduced for lightweight applications, then weight is improved, but heat dissipation capability deteriorates due to reduced thermal mass and surface area
Solution Approach 1:
The cable uses thin-film insulation layers and flexible polymer sheaths instead of thick rigid insulation. These thin films provide adequate electrical insulation while minimizing thermal resistance, allowing efficient heat dissipation from the conductors to the external environment, thus maintaining low cable weight with adequate heat dissipation capability
Solution Approach 2:
The cable employs composite material structures combining different polymers with optimized thermal and electrical properties. The insulation uses materials with high dielectric strength but low thermal mass, while the outer jacket incorporates heat-dissipating materials, achieving lightweight construction with maintained heat dissipation performance
4Temperature
If air cooling is used for cable temperature control, then cooling effectiveness is improved at sea level, but cooling effectiveness deteriorates at high altitude due to low air density
Solution Approach 1:
The cable structure itself provides thermal management through its material composition and geometry. The insulation materials are selected for their inherent thermal conductivity properties, and the cable cross-section is designed to maximize surface-area-to-volume ratio, enabling passive heat dissipation that is effective across varying air density conditions without requiring active cooling systems
Solution Approach 2:
The cable's thermal parameters are optimized for high-altitude operation. The insulation thickness and material thermal conductivity are selected to provide adequate heat dissipation in low-air-density environments, where convective cooling is less effective. This ensures consistent temperature control across different altitudes
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
The cable efficiently transmits high-power, high-voltage signals with low resistive losses and high heat tolerance, effectively counteracting skin and proximity effects, and reducing the risk of partial discharges, making it suitable for high-altitude applications.
Implementation Method 1
each of the metallic wires alternates between outer positions and inner positions in the bundle along a longitudinal extension of the electrical cable in order to counteract skin effect in the bundle
Implementation Method 2
Conductors and insulation of an electrical cable conveying these levels of power and voltage between the power source and the electric motor would be subject to risk of partial discharge due to the high voltages
Data Source
AI summary
Low-loss lightweight high-power kilohertz alternating-current high-voltage electrical cables 1 usable in low pressure having a bundle 2 of metallic wires 3 being separated from each other by non-conductor layers 4 provided on the individual metallic wires, wherein the metallic wires 3 alternate between outer positions 5 and inner positions 6 in the bundle along a longitudinal extension 7 of the electrical cable in order to counteract skin effect in the electrical cable bundle 2, as well as enabling counteraction of proximity effect, when in use, an inner semi-conductive layer 8 of broad range temperature rated polymeric material surrounding said bundle 2 of metallic wires 3, and an insulating layer 9 of broad range temperature rated polymeric material surrounding and bonded to the inner semi-conductive layer 5, at least one of the metallic wires 3 being in electric contact with the inner semi-conductive layer 8 as well as a manufacturing method.