Arched OLTC Barrier Structure for Pressure-Resistant Tap Changers
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Solution Overview
Problem
Conventional On-Load Tap Changer (OLTC) barrier systems are bulky, difficult to manufacture with homogeneous materials, prone to stress and deformation under electrical fields, and face challenges in withstanding pressure changes, leading to potential contamination of transformer fluids.
Innovation Solution
An arched-shaped barrier with phase holes for galvanic connection between diverter switch and tap selector units, made from materials like epoxy glass, allowing for a thinner, more compact design that withstands pressure changes and electrical stress without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a flat and thick backboard is used to withstand pressure differences and structural deformations, then the barrier can protect against pressure changes, but it takes up much space and is difficult to manufacture with homogeneous materials
Solution Approach 1:
The backboard is designed with an arched curvature instead of being flat. This arch shape allows the backboard to withstand pressure differences more effectively while being thinner, thus reducing the space occupied by the barrier while maintaining or improving its pressure resistance capability.
2Strength
If a thick backboard is used to withstand pressure differences, then the barrier can protect against pressure changes, but it is difficult to stress release from strong electrical fields and prone to shrinkage cracks and internal blisters
Solution Approach 1:
The arched shape of the backboard improves stress distribution, allowing for better stress release from electrical fields and reducing the likelihood of shrinkage cracks and internal blisters during manufacturing, thereby improving overall reliability.
Solution Approach 2:
The use of epoxy glass systems in the arched backboard provides a composite material solution that maintains structural integrity while being more resistant to manufacturing defects such as shrinkage cracks and internal blisters.
3Strength
If a thick barrier is used to withstand pressure differences, then the barrier can protect against pressure changes, but it reduces the number of manufacturing methods being possible to use
Solution Approach 1:
The arched backboard design enables the use of various manufacturing methods including filament winding and other composite manufacturing techniques, providing greater manufacturing flexibility compared to flat thick barriers while maintaining pressure resistance.
4Ease of manufacture
If a flat backboard is used, then the barrier can be manufactured, but it deforms under pressure changes like flexing inward or outward
Solution Approach 1:
The arched shape of the backboard provides inherent structural stability against pressure changes, preventing the flexing inward or outward deformation that occurs with flat backboards, while still being manufacturable using appropriate processes.
Data Source
Figure 1~2
Figure 3
AI summary
The present disclosure relates to an On-Load Tap Changer (OLTC) (1) for a fluid-filled power transformer. The OLTC comprises a barrier (2) which is sealingly arranged to separate an electrically insulating tap changer fluid (3) of the OLTC from an electrically insulating transformer fluid (13) in a transformer tank of the power transformer. The OLTC also comprises a diverter switch unit (4) arranged in the tap changer fluid and fixed to an inside surface (9a) of a backboard (16) of the barrier. The OLTC also comprises a tap selector unit (5) arranged in the transformer fluid and fixed to an outside surface (9b) of the backboard. The diverter switch unit and the tap selector unit are galvanically connected with each other via phase holes in the backboard, and the backboard is arched.