Cable Mounting Device for Common Mode Current Reduction
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Solution Overview
Problem
High power transmission applications, such as in wind turbines, face challenges with common mode currents and electromagnetic compatibility due to the impractical dimensions and temperature limitations of standard 6-core cables, which are stiff and difficult to handle, and require additional space for bending, and have limited temperature capacity.
Innovation Solution
A mounting device that fixes three separately isolated one-phase power cables and one or more common mode return cables in a symmetrical cross-sectional pattern, allowing for customizable conductor dimensions and insulation materials, enabling higher temperature operation and reduced EMC issues, with the option for custom-made polymeric or metallic structures using 3D printing or molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard 6-core cables are used for high power transmission, then common mode current conduction is provided, but the cable dimensions become impractical and weight becomes difficult to handle
Solution Approach 1:
The invention divides the single 6-core cable into separate cables: three single-core power cables for main current and three separate single-core common mode cables. This segmentation allows each cable to be optimized independently, reducing overall weight while maintaining common mode current conduction capability.
Solution Approach 2:
The invention applies different cable specifications locally: power cables are sized for main current carrying capacity while common mode cables are sized appropriately for common mode current return paths. This local optimization prevents over-sizing all cables to the same dimension, reducing total weight.
2Reliability
If standard 6-core cables are used for high power transmission, then common mode current conduction is provided, but the cable stiffness increases and handling becomes difficult
Solution Approach 1:
Dividing the rigid 6-core cable into separate single-core cables dramatically improves flexibility and handling ease. Each thin single-core cable can be easily routed, bent, and installed compared to the stiff multi-core cable, while still providing the required common mode current path when bundled together.
Solution Approach 2:
The invention changes the structural parameter from a single multi-core cable to multiple single-core cables. This parameter change transforms the physical properties from stiff and hard to handle to flexible and easy to install, while maintaining the electrical function through proper arrangement.
3Reliability
If standard 6-core cables are used for high power transmission, then common mode current conduction is provided, but the cable curvature is limited and extra space is required for bending
Solution Approach 1:
Separate single-core cables can be bent to much tighter radii than a single 6-core cable. The segmentation allows each cable to follow its own curvature path independently, reducing the space required for cable routing and installation in confined areas like turbine nacelles.
Solution Approach 2:
The invention allows cables to be arranged in three-dimensional space more efficiently. Separate cables can be routed through different paths and dimensions, optimizing space utilization compared to the constrained two-dimensional routing of a single stiff cable.
4Reliability
If standard 6-core cables are used for high power transmission, then common mode current conduction is provided, but the isolation material temperature capacity is limited to 90°C
Solution Approach 1:
The invention changes the temperature parameter by selecting high-temperature rated insulation materials (100°C, 120°C, or higher) for the separate power and common mode cables. This parameter change allows the cable system to operate in high-temperature environments near generators while maintaining common mode current conduction capability.
Solution Approach 2:
The invention uses composite cable constructions with high-temperature rated insulation materials that combine electrical insulation properties with thermal resistance. These composite materials enable operation at temperatures exceeding the 90°C limit of standard cables.
Data Source
AI summary
A mounting device shaped for contact with at least a part of a circumference formed by a configuration of three separately electric isolated one-phase power cables and at least one electrically isolated one-phase common mode return cable positioned together so that electrically conductive portions of the respective cables form a symmetrical cross sectional pattern, wherein the mounting device is arranged for fixation of all of said three power cables and the at least one common mode return cable to an associated structure. This mounting device allows effective fixation of power cables in electric power systems involving a three-phase PWM converter, where common mode return cables are necessary, e.g. in a wind turbine. The mounting device allows an effective practical handling and freedom to choose cables with custom fit cross sectional areas as well as compliance with the required maximum temperatures.