Power Cable Iron Loss Reduction via Symmetrical Ground Bus Arrangement
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Solution Overview
Problem
Conventional POF cables experience increased maintenance costs and environmental issues due to oil leakage, and have reduced transmission capacity and current carrying capacity due to iron loss, which is higher compared to cross-linked poly-ethylene cables.
Innovation Solution
A power cable configuration with three transmission cables and ground buses arranged at three-fold rotationally symmetrical positions inside a steel pipe, where the transmission cables have outer diameters that inscribe a circle corresponding to the maximum radius within the pipe, and the ground buses have diameters that project radially but are less than or equal to the circle's diameter, maximizing cross-sectional areas and reducing iron loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating paper thickness is increased to provide adequate electrical insulation in crosslinked poly-ethylene cables, then the insulation reliability is improved, but the conductor size is limited to 1000 mm2 or less in cross section due to the fixed internal diameter of the steel pipe
Solution Approach 1:
The patent transitions from a 2D cross-sectional arrangement to a 3D spatial configuration by arranging three transmission cables at three-fold rotationally symmetrical positions within the steel pipe. This three-dimensional arrangement optimizes the use of available space, allowing larger conductor cross-sectional areas while maintaining adequate insulating paper thickness for electrical insulation.
Solution Approach 2:
The patent changes the geometric parameters of the cable arrangement by specifying that transmission cables are positioned at three-fold rotationally symmetrical positions with their outer diameters inscribing a circle that corresponds to the maximum radius within the steel pipe. This parameter optimization enables larger conductor sizes while preserving insulation reliability.
2Stability of the object's composition
If the 3-phase transmission cables are arranged at 3-fold rotationally symmetrical positions within the magnetic steel pipe, then the structural symmetry and insulation are improved, but the iron loss increases significantly reducing transmission capacity
Solution Approach 1:
The patent extracts the ground buses from the conventional cable structure and positions them separately at three-fold rotationally symmetrical positions within the steel pipe. This separation allows the transmission cables to be arranged optimally for structural symmetry while the ground buses are positioned to minimize their impact on iron loss, thereby reducing overall energy loss.
Solution Approach 2:
The patent introduces ground buses as intermediary elements that mediate between the transmission cables and the steel pipe. These ground buses are positioned at three-fold rotationally symmetrical positions and make contact with the outer peripheral surfaces of adjacent transmission cables, providing electrical grounding while allowing the transmission cables to maintain their optimal symmetric arrangement for reduced iron loss.
3Productivity
If the conductor size is increased to improve transmission capacity, then the power transmission capability is improved, but the outer diameter of the transmission cables increases beyond the limit imposed by the steel pipe internal diameter
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement by positioning transmission cables at three-fold rotationally symmetrical positions within the steel pipe. This 3D configuration allows larger conductor cross-sectional areas for improved transmission capacity while keeping the outer diameter within the steel pipe's internal diameter limits.
Solution Approach 2:
The patent optimizes geometric parameters by specifying that transmission cable outer diameters inscribe a circle corresponding to the maximum radius within the steel pipe. This parameter optimization enables maximum conductor size for improved transmission capacity while maintaining compatibility with the fixed steel pipe internal diameter.
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 configuration reduces iron loss and increases transmission power by maximizing the cross-sectional areas of the transmission cables and ground buses, enhancing the power cable's efficiency and current carrying capacity.
Implementation Method 1
transmission capacities of the POF cables decrease due to iron loss
Implementation Method 2
three conductor wires configured to transmit 3-phase alternating current power
Implementation Method 3
three ground buses respectively making contact with outer peripheral surfaces of two adjacent transmission cables
Data Source
AI summary
A power cable to be provided inside a steel pipe that is electrically connected to a reference potential node, includes 3 transmission cables, 3 ground buses making contact with outer peripheral surfaces of adjacent transmission cables and arranged at 3-fold rotationally symmetrical positions with respect to a center of the transmission cables in a cross sectional view, a binder covering the ground buses and the transmission cables, and a jacket provided to overlap the binder. The transmission cables have outer diameters to inscribe a first circle having a radius corresponding to a radius of a second, envelope circle of the power cable having a maximum radius inside the steel pipe, but excluding thicknesses of the binder and the jacket. The ground buses have outer diameters to project outwardly of an envelope closed curve of the transmission cables, but less than or equal to a diameter of the first circle.