Oil Transformer Cooling via Segmented Chamber and Axial Clamping
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Solution Overview
Problem
Current oil transformers face challenges in manufacturing complexity and cooling efficiency due to the direct assembly of heavy transformer windings on oil chambers, leading to suboptimal cooling performance as heated oil mixes with unheated oil, reducing the effectiveness of the cooling system.
Innovation Solution
The design features a monolithic oil chamber with rib-like spacer elements and a configuration that allows oil to flow upwards through axial cooling channels, with separate outlets to an external cooling system, enhancing natural convection and maintaining high temperature differences for improved cooling, while also providing mechanical reinforcement through axial clamping structures to withstand short-circuit forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transformer windings are assembled directly on top of the oil chamber, then the assembly process becomes complex and difficult to manufacture, but the cooling efficiency deteriorates as heated oil mixes with unheated oil
Solution Approach 1:
The oil chamber is segmented into an upper chamber and a lower chamber separated by a partition wall. The partition wall includes openings that allow oil flow between chambers while maintaining separation. This segmentation prevents mixing of heated and unheated oil, improving cooling efficiency while keeping the assembly process manageable.
Solution Approach 2:
The partition wall acts as an intermediary structure between the upper and lower oil chambers. It controls the oil flow path through openings, ensuring that cooled oil from the lower chamber flows to the coil axles without completely mixing with the heated oil in the upper chamber, thus maintaining temperature differences and cooling effectiveness.
2Device complexity
If an oil chamber with perforated panels is used to enable oil passage to the transformer winding, then the structure becomes complex with multiple components, but the oil flow effectiveness improves
Solution Approach 1:
The oil chamber structure is segmented into functional zones: an upper chamber for heated oil, a lower chamber for cooled oil, and a partition wall with openings. This segmentation replaces the need for complex perforated panels while maintaining effective oil passage to the coil axles, simplifying the overall structure.
Solution Approach 2:
Instead of using horizontal perforations in a flat panel, the design uses vertical openings in a partition wall that extends in the vertical dimension. This dimensional change allows oil to flow from the upper chamber to the lower chamber and then to the coil axles, maintaining cooling effectiveness while reducing structural complexity.
3Strength
If the transformer coil is mechanically strengthened with axial clamping structures, then the mechanical strength increases to withstand short-circuit forces, but the oil flow path through the clamping structures becomes more difficult to design
Solution Approach 1:
The axial clamping structures serve multiple functions: they provide mechanical strengthening to withstand short-circuit forces and simultaneously act as oil flow passages. The clamping structures are designed with openings or channels that allow oil to pass through, combining mechanical support and cooling functions in a single component, thus reducing overall device complexity.
Solution Approach 2:
The mechanical clamping function and the oil flow function are merged into the same structural elements. The clamping structures at both ends of the coil not only secure the coil mechanically but also facilitate oil flow to and from the coil axles, eliminating the need for separate cooling components and simplifying the design.
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 simplifies assembly, enhances cooling efficiency by maintaining high oil temperatures, and increases the transformer's mechanical strength to handle short-circuit forces, improving both manufacturing ease and operational performance.
Implementation Method 1
the oil is on one side insulation medium and on the other side cooling medium. Typically the oil circulates inbetween cooling channels through the coil windings, where heat losses are generated during operation of the transformer
Implementation Method 2
The circulation of the oil might be generated by a pump for example but also natural convection is possible
Data Source
Figure 1
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Figure 4~5
AI summary
The invention is related to an oil transformer (10), comprising a transformer vessel (12), a transformer core mounted (14) therein, at least one upright hollow cylindrical transformer coil (16, 18) with at least one axial cooling channel (34, 36) arranged around a limb (28) of the transformer core (14) and an oil chamber (20, 22, 60, 80, 90) arranged at an axial front side of the transformer coil (16, 18). At least one first opening (86, 87, 88) leading from the inner chamber (100) to the belonging front side of the transformer coil (16, 18) is foreseen and at least one second opening (70) is foreseen within the surrounding boundaries (64, 66, 94, 96) of the oil chamber (20, 22, 60, 80, 90). The oil chamber (20, 22, 60, 80, 90) is an under-pressure chamber, wherein the at least one first opening (86, 87, 88) is an inlet port and the at least one second opening (70) is an outlet (78) port.