Corona Shielding on High-Voltage Winding Bars
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Solution Overview
Problem
Current methods for forming corona protection on high-voltage machine winding bars are complex and costly, with abrupt transition points leading to high field strengths and potential damage due to thermal and electrical stress.
Innovation Solution
A method and device that apply a continuous corona protection by varying the filler proportions in a carrier material-based composition, creating a seamless transition between end and outer corona protection using dopable semiconductor materials, allowing for a single production step and improved electrical and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate compositions with different fillers are used for end corona protection and outer corona protection, then the electrical resistance can be optimized for each section, but the manufacturing process becomes complex and costly with abrupt transition points
Solution Approach 1:
The patent applies parameter changes by continuously varying the proportion of conductive filler (graphite) and semi-conductive filler (silicon carbide) in the composition along the length of the corona protection. This allows the electrical resistance to be optimized for each section (end and outer corona protection) while maintaining a single continuous application process, avoiding abrupt transitions and manufacturing complexity
Solution Approach 2:
The patent implements local quality by creating different electrical resistance characteristics in different sections of the corona protection through localized variation of filler proportions. The end corona protection has higher resistance while the outer corona protection has lower resistance, with a smooth transition zone between them, all achieved within a single continuous composition application
2Reliability
If abrupt transition points are created between end and outer corona protection, then distinct functional zones are defined, but high field strengths occur leading to thermal and electrical stress
Solution Approach 1:
The patent applies dynamics by creating a dynamic, continuously varying electrical resistance profile along the corona protection rather than static abrupt transitions. The filler proportions change gradually along the length, creating a smooth gradient in electrical properties that dynamically adapts to the different functional requirements of end and outer corona protection zones while eliminating stress concentration points
Solution Approach 2:
The patent implements curvature in the electrical resistance profile by using a smooth, continuous transition between different resistance zones rather than sharp angular transitions. This curved gradient in electrical properties eliminates the abrupt boundaries that would create high field strengths, distributing the electrical stress evenly throughout the transition zone
3Manufacturing precision
If multiple production steps are used for applying different corona protections, then precise control over resistance distribution is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent merges multiple corona protection applications into a single continuous process by using one composition containing both conductive and semi-conductive fillers. The different filler proportions are distributed along the length during a single application, combining what would traditionally require separate production steps into one efficient operation that maintains precise resistance control
Solution Approach 2:
The patent creates a universal composition that serves multiple functions simultaneously - providing both end corona protection and outer corona protection with their respective resistance requirements in a single material application. This multi-functional composition eliminates the need for separate materials and application steps for different corona protection zones
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 method simplifies and cost-effectively forms corona protection with continuous transition, reducing thermal and electrical stress and enhancing stability, thereby preventing potential jumps in field strength and extending the lifespan of high-voltage machine components.
Implementation Method 1
the first and the second filler containing the same dopable semiconductor material whose doping determines the electrical resistance of the first and second filler
Implementation Method 2
the electrical resistance of the first composition decreases along the first section (9) in the direction of the second section (11)
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a method for forming corona shielding (7) on a winding bar (4) for high-voltage machines (1), having end corona shielding (8) in a first section (9) and outer corona shielding (10) in a second section (11) that adjoins the first section (9), said method comprising the following steps: provision (S1) of a first composition, which comprises a carrier material and a first filler contained therein and having a first electrical resistance; provision (S1) of a second composition, which comprises the same carrier material and a second filler contained therein and having a second electrical resistance, wherein the first and second fillers contain an identical dopable semiconductor material, the doping of which determines the electrical resistance of the first and second fillers, and wherein the second resistance differs from the first resistance; application (S2) of the first composition in the first section (9) to form the end corona shielding (8); and application (S2) of the second composition in the second section (11) to form the outer corona shielding (10). The same carrier material and fillers having the same properties are used for both compositions, and therefore the corona shielding with the end corona shielding and the outer corona shielding can be formed in one go (one single production step). The invention also relates to a device (19) for forming corona shielding (7) on a winding bar (4) for high-voltage machines (1).