High-Voltage Bushing Moisture Barrier Design
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Solution Overview
Problem
High-voltage outdoor bushings face issues with increased dissipation factor during storage and operation due to moisture absorption, leading to reduced reliability and higher manufacturing costs, especially under severe weather conditions.
Innovation Solution
Incorporating a moisture diffusion barrier within the condenser core, loaded with inorganic filler powder, to prevent moisture from entering the core, which is then moulded with a polymeric weather protection housing, enhancing storage and operation stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polymeric weather protection housing is directly moulded on the condenser core, then manufacturing costs are reduced and the bushing cap becomes unnecessary, but the dissipation factor increases considerably during extended storage and operation
Solution Approach 1:
The invention divides the weather protection housing into two functional segments: a rigid polymeric housing providing mechanical protection and a separate hydrophobic coating layer providing electrical insulation and moisture resistance. This segmentation allows each layer to perform its specific function optimally, preventing the dissipation factor increase observed in directly moulded single-layer housings.
Solution Approach 2:
The invention uses a composite structure combining a rigid polymeric housing material with a hydrophobic coating material. This composite approach leverages the mechanical strength of the rigid polymer and the electrical/moisture-resistant properties of the hydrophobic coating, resolving the contradiction between manufacturing simplicity and long-term reliability.
2Reliability
If porcelain is used as insulation material, then traditional reliability is maintained, but the bushing becomes heavy and vulnerable to vandalism and earthquake
Solution Approach 1:
The invention replaces traditional porcelain insulators with a polymeric housing that, while potentially less mechanically robust than porcelain, provides sufficient service life for outdoor applications. The polymeric material offers advantages in weight reduction and resistance to vandalism and earthquake, while the hydrophobic coating ensures long-term electrical reliability.
Solution Approach 2:
The invention changes the material parameter from porcelain to polymeric material, fundamentally altering the weight, mechanical strength, and environmental resistance characteristics of the bushing. This parameter change enables the bushing to be lightweight and resistant to vandalism and earthquake while maintaining insulation reliability through the hydrophobic coating.
3Ease of manufacture
If the condenser core is impregnated with resin during heating and vacuum process, then the bushing becomes dry and oil-free, but moisture can still penetrate during extended storage under severe weather conditions
Solution Approach 1:
The invention applies a hydrophobic coating to the outer surface of the polymeric weather protection housing before the bushing enters service. This preliminary action creates a moisture-barrier layer that prevents water penetration during extended storage and operation, complementing the internal resin impregnation that already provides dry construction.
Solution Approach 2:
The hydrophobic coating acts as a flexible thin film layer on the outer surface of the polymeric housing. This thin film provides effective moisture protection while allowing the underlying polymeric structure to maintain its mechanical properties and weather resistance.
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 moisture diffusion barrier significantly reduces water penetration, maintaining low dissipation factors even under hot and wet conditions, extending the bushing's operational and storage life while reducing manufacturing costs.
Implementation Method 1
moisture diffusion barrier which limits moisture to enter deeply into the condenser core
Implementation Method 2
The particles of the filler power significantly reduce the diffusion coefficient of the condenser core since the filler particles of the inorganic filler powder reduce the effective length of the diffusion path of water molecules
Data Source
AI summary
The high-voltage outdoor bushing comprises a conductor (2) extended along an axis (1 ), a condenser core (3) and an electrically insulating polymeric weather protection housing (7) moulded on the condenser core (3). The condenser core (3) contains an electrically insulating tape (4) which is wound in spiral form around the conductor (2), capacitance grading insertions (5) arranged between successive windings of the tape (4) and a cured polymeric insulating matrix embedding the wound tape (4) and the capacitive grading insertions (5). A moisture diffusion barrier is incorporated inside the condenser core (3) prior to moulding the weather protection housing (7). Such a bushing is distinguished by an excellent storage and operation stability under hot and wet weather conditions.