Modular Capacitor Unit for HVDC Converter Stations
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Solution Overview
Problem
Current high voltage direct current (HVDC) converter stations are bulky and difficult to install and transport, particularly for offshore applications, due to the large, monolithic design of capacitor units which complicates maintenance and increases space requirements.
Innovation Solution
A capacitor unit composed of multiple detachable pieces that form a hollow body, allowing for easier handling, reduced weight, and improved accessibility for maintenance, while also reducing Eddy currents and optimizing insulation design with a circular or rounded shape, facilitating a more compact and efficient power converter station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a monolithic capacitor unit design is used, then structural integrity is improved, but ease of installation and transport deteriorates
Solution Approach 1:
The capacitor unit is divided into a modular structure comprising a hollow body formed by multiple detachable pieces (first piece, second piece, third piece, fourth piece). Each piece can be separately manufactured, transported, and assembled, solving the transport and installation difficulty while maintaining structural integrity through standardized connection interfaces between pieces
2Ease of manufacture
If a single-piece capacitor unit is used, then manufacturing simplicity is improved, but ease of repair and maintenance deteriorates
Solution Approach 1:
The hollow body is constructed from multiple detachable pieces that can be assembled in a factory setting using standardized connections. This modular design allows individual pieces to be replaced or maintained in the field without disassembling the entire capacitor unit, significantly improving maintenance accessibility while keeping manufacturing processes standardized and simple
Solution Approach 2:
The detachable pieces are designed to be easily removed from the hollow body structure, allowing maintenance personnel to extract and replace individual components (such as capacitor elements or cooling components) without affecting the entire unit, thus enabling targeted maintenance operations
3Strength
If a solid block capacitor design is used, then structural strength is improved, but weight and space efficiency deteriorates
Solution Approach 1:
The hollow body design incorporates empty spaces and cavities within the structural framework, reducing the overall material consumption and weight compared to a solid block design. The hollow structure maintains structural strength through optimized wall thickness and geometric configuration while achieving significant weight reduction for the capacitor unit
Data Source
Figure 1~2A
Figure 2B~3
Figure 4~5A
AI summary
The present disclosure relates to a capacitor unit (100) comprising a hollow body extending along an axial direction (108). The body includes a plurality of pieces (101-104) and each piece forms a section of the hollow body. At least one of the pieces is a detachable section of the hollow body and a piece includes at least one capacitor element. The present disclosure relates also to a converter cell comprising such a capacitor unit and to a valve unit comprising a plurality of such converter cells. The valve unit may form part of a converter in a high voltage direct current converter station.