Thermally Stabilized Insulation Paper for High-Temperature Transformers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrical insulation papers, particularly those used in liquid-immersed transformers, suffer from rapid ageing due to thermal, chemical, and oxidant stresses, leading to a loss of tensile strength and potential failure, while there is a desire for smaller transformers that can operate at higher temperatures without compromising electrical insulation.
Innovation Solution
An electrical insulation paper comprising at least 25% cellulose fibers, 5% synthetic fibers (such as aliphatic polyamide or glass fibers), and a thermal stabilizer with 1-4% nitrogen content, which enhances thermal stability and mechanical strength, allowing for higher operating temperatures and improved tensile strength retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional kraft paper or cellulose acetate paper is used for insulation, then the paper can be manufactured with basic insulation properties, but the paper lacks sufficient oil immersion resistance and allows bacterial growth in moisture-containing oil environments
Solution Approach 1:
The patent applies composite material principle by combining cellulose base paper with bitumen coating to create a composite insulation paper that integrates the mechanical strength of cellulose with the water-repellent and bacteria-resistant properties of bitumen, achieving both oil immersion resistance and prevention of bacterial growth
Solution Approach 2:
The patent applies parameter changes by modifying the chemical composition and surface properties of the insulation paper through bitumen impregnation and coating, transforming the paper from hydrophilic to hydrophobic to prevent bacterial growth in oil environments while maintaining insulation performance
2Reliability
If insulation paper is impregnated with moisture-containing oil, then the paper provides electrical insulation, but water separates from the oil and forms channels causing electrical breakdown
Solution Approach 1:
The patent applies parameter changes by modifying the surface energy and hydrophobicity of the paper through bitumen treatment, enabling the paper to maintain homogeneous oil impregnation without water separation, thus preserving electrical insulation properties
Solution Approach 2:
The patent applies local quality principle by creating a bitumen-rich surface layer on the paper that specifically addresses water separation at the paper-oil interface, while the bulk paper structure maintains its insulation properties, achieving localized prevention of water channel formation
3Reliability
If resin is used to improve oil immersion resistance, then the paper resists oil degradation, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent applies parameter changes by using bitumen instead of resin, fundamentally changing the chemical approach from complex resin cross-linking to simpler bitumen impregnation and coating processes, reducing manufacturing complexity while maintaining oil immersion resistance
Solution Approach 2:
The patent applies the principle of using readily available, inexpensive bitumen material that can be applied through simple processes, replacing expensive and complex resin systems, making the solution more economically viable and easier to manufacture
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 insulation paper exhibits a higher Relative Thermal Endurance index, enabling it to withstand higher temperatures and maintain mechanical strength, facilitating the use of smaller transformers or those with increased operating temperatures without compromising electrical insulation.
Implementation Method 1
the bitumen on the paper surface forms a barrier that prevents water from penetrating into the paper structure
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This disclosure relates to an electrical insulation paper comprising at least 25% content by weight of cellulose fibers based on the total weight of the electrical insulation paper, 8% content by weight of synthetic fibers based on the total weight of the electrical insulation paper, and a thermal stabilizer comprising nitrogen, wherein a content by weight of the nitrogen constitutes between 1% and 4% of the content by weight of the cellulose fibers.