Double-Walled Transformer Enclosure for Low-Frequency Noise Reduction
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Solution Overview
Problem
Existing electrical equipment such as transformers and reactors face challenges in reducing noise generated by magnetostriction and electromagnetic forces, particularly low-frequency noise, which is difficult to diminish due to technical limitations and increasing noise emission criteria, with existing solutions being unsatisfactory in terms of feasibility and effectiveness.
Innovation Solution
A double-walled housing design with stiffeners and mechanical decoupling devices to isolate noise, using acoustics absorbent materials and expansion joints to reduce noise transmission, and maintaining a vacuum or specific gas pressure within the intermediate volume to enhance noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If reduction of magnetic induction is used to reduce noise, then noise level is reduced, but energy losses increase
Solution Approach 1:
An intermediate volume filled with sound-absorbing material is introduced between the inner wall (containing the electric system) and the outer wall. This intermediary layer absorbs noise vibrations without requiring changes to the magnetic induction level, thus reducing noise while maintaining optimal energy efficiency of the electric system.
Solution Approach 2:
The enclosure is segmented into multiple walls (inner wall, outer wall) with an intermediate space between them. This segmentation allows the noise reduction function to be separated from the electric system itself, enabling noise control without affecting the system's energy performance.
2Object-generated harmful factors
If increasing the global size of the transformer is used to reduce noise, then noise reduction is achieved, but more insulating oil and material are required
Solution Approach 1:
Instead of reducing noise by increasing the overall size of the transformer, the solution introduces a new dimensional layer - the intermediate volume with sound-absorbing material between the inner and outer walls. This allows noise reduction without proportionally increasing the total volume or material requirements.
3Object-generated harmful factors
If designing absorbing enclosures with sound absorbing material is used to reduce noise, then noise reduction is achieved, but cost increases and specific adaptations are required
Solution Approach 1:
The intermediate volume serves multiple functions: it absorbs noise vibrations, provides thermal insulation, and allows space for cooling channels. This multi-functionality reduces the need for separate structural adaptations and simplifies the overall design while achieving noise reduction.
4Object-generated harmful factors
If low frequency noise is targeted for reduction, then noise quality is improved, but it is very difficult to diminish due to long wavelengths
Solution Approach 1:
The sound-absorbing material in the intermediate volume is designed as a composite structure with specific density and porosity characteristics that are particularly effective at absorbing low-frequency vibrations. This composite approach enables effective noise reduction across the full frequency spectrum, including difficult-to-control low frequencies.
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 solution effectively reduces noise emissions in horizontal directions, achieving significant noise reduction across various frequencies, including low frequencies, while maintaining structural integrity and environmental compatibility.
Implementation Method 1
this intermediate volume being intended to isolate the noise generated by the electric system contained in the internal space
Implementation Method 2
this housing comprising stiffeners at the inner face of the outer wall, characterized in that these stiffeners comprise each a main plate and a perpendicular plate welded to the main plate
Implementation Method 3
the outer wall is made of panels having their edges welded to the perpendicular plates of the outer stiffeners
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a housing (1) for an electric apparatus such as a transformer, comprising an enclosure (2) delimiting an internal space (6) intended to be filled with dielectric gas or insulating oil, this enclosure (2) comprising a bottom part (4) and a surrounding part (3) surrounding all the internal space (6). At least the surrounding part (3) comprises an inner wall (7) and an outer wall (8) at a distance from each other to define a single intermediate volume (9) which extends all along the surrounding part, this intermediate volume (9) being intended to isolate the noise generated by the electric system mounted in the internal space (6).