Transformer Shielding Layer Grounding for Power Density
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Solution Overview
Problem
Traditional high-voltage transformers face challenges such as large size, heavy weight, high no-load loss, lack of automatic fault isolation, and safety hazards due to insulation failures and external high-voltage potentials, which hinder power density and safety in power distribution systems.
Innovation Solution
A high-voltage transformer design featuring a primary coil unit with a shielding layer and insulating portion, an outgoing wire terminal, and a connecting wire with an insulating sleeve, allowing for flexible placement and reduced size while ensuring safety compliance by maintaining a specific distance from the shielding layer, thereby enhancing power density and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If air is used as main insulation against ground, then the transformer structure is simple, but larger insulation size is required and power density cannot be increased
Solution Approach 1:
The patent changes the insulation medium from air to epoxy resin, fundamentally altering the insulation parameter. Epoxy resin has much higher insulation strength than air, allowing the insulation size to be reduced significantly while maintaining the same voltage rating, thus resolving the contradiction between structural simplicity and insulation size.
Solution Approach 2:
The patent uses composite materials by combining epoxy resin with fiberglass reinforcement and aluminum foil shielding layers. This composite structure provides both mechanical strength and electrical insulation properties, achieving compact size while maintaining structural integrity and insulation performance.
2Reliability
If oil is used as main insulation against ground, then insulation performance is improved, but shell and flammable insulating oil are required creating safety hazards
Solution Approach 1:
The patent replaces expensive and hazardous insulating oil with a solid epoxy resin encapsulation that permanently seals the transformer components. This eliminates the need for ongoing oil maintenance and removes the fire hazard associated with oil-filled transformers, resolving the contradiction between insulation performance and safety.
Solution Approach 2:
The epoxy resin creates an inert, sealed environment around the transformer windings and core, preventing oxidation and eliminating the flammable atmosphere that would exist with oil insulation. This provides both superior insulation performance and inherent safety by removing combustible materials.
3Ease of manufacture
If integrated epoxy resin cast transformer is manufactured, then manufacturing is simplified, but safety isolation is hard to make between high-voltage and low-voltage sides
Solution Approach 1:
The patent segments the transformer into distinct high-voltage and low-voltage winding sections, with the aluminum foil shielding layer positioned between them. This segmentation allows the epoxy resin to provide mechanical encapsulation while the foil layer provides electrical isolation, resolving the contradiction between manufacturing simplicity and safety isolation.
Solution Approach 2:
The aluminum foil shielding layer acts as an intermediary between the high-voltage and low-voltage windings. It provides a grounded barrier that electrically isolates the two sides while being easily incorporated into the epoxy casting process, thus maintaining manufacturing simplicity while ensuring safety isolation.
4Reliability
If safety distance is taken into account for external high-voltage potential, then safety is improved, but power density cannot be increased
Solution Approach 1:
The patent nests multiple functional layers within the transformer structure: the aluminum foil shielding layer is nested within the epoxy resin encapsulation, which in turn encloses the windings and core. This nested arrangement provides safety isolation and high-voltage containment within a compact volume, resolving the contradiction between safety distance requirements and power density.
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 design improves safety performance by grounding the shielding layer, reduces transformer size, and increases power density by allowing flexible placement in limited spaces while meeting safety regulations.
Implementation Method 1
a shielding layer covering an outer surface of the first insulating portion, the shielding layer including an opening
Implementation Method 2
a first insulating portion configured to wrap and fix the primary winding; an insulating sleeve partially wrapping the connecting wire
Data Source
AI summary
A transformer includes a primary coil unit including a primary winding, a first insulating portion and a shielding layer, wherein the first insulating portion wraps the primary winding, the shielding layer covers an outer surface of the first insulating portion, the shielding layer includes an opening, and a part of the first insulating portion is exposed at the opening; an outgoing wire terminal in the opening and having a first portion and a second portion connected with each other, the first portion coupled to the primary winding and wrapped by the first insulating portion, the second portion being exposed out of the first insulating portion; a connecting wire having a first end connected to the second portion of the outgoing wire terminal; and an insulating sleeve partially wrapping the connecting wire, and a second end of the connecting wire being exposed out of the insulating sleeve, (FIG. 17).