Cast Polymer Base for Current Transformer Bushings

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Solution Overview

Problem

Current transformers used for measuring high-intensity alternating currents face challenges in sustaining such high levels of intensity, requiring conversion through a current transformer with complex base elements that need to withstand mechanical stress and seismic situations, while existing solutions involve multiple machined metallic parts and complex assemblies.

Innovation Solution

A base element for current transformers made from a single block of cast polymer resin or concrete material, embedding all components including secondary leads, plugs, securing means, and an oil drain, which simplifies manufacturing and reduces production costs by eliminating the need for multiple machined parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple machined metallic parts and complex assemblies are used for the base element, then the structural strength and reliability are improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvestructural strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges multiple separate metallic components (base plate, pedestals, bushings, securing elements) into a single integrated base element made of polymer concrete. This consolidation maintains the structural strength required to support the transformer while eliminating the complexity of assembling multiple machined parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses polymer concrete, a composite material combining cement, polymer resin, and filler materials, to create a base element that provides both the necessary mechanical strength and structural integrity while allowing for integrated manufacturing of multiple functional components in a single piece.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple machined metallic parts are used for the base element, then the reliability is improved, but the manufacturing cost and assembly time increase

Engineering Contradiction:
ImprovereliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple manufactured components into one monolithic base element produced through casting. This eliminates the need for separate machining operations and assembly processes for each component, significantly reducing manufacturing cost and assembly time while maintaining reliability through the integrated structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base element is manufactured as a complete, integrated unit with all functional features (mounting surfaces, bushings, securing elements) pre-formed during the single casting process. This preliminary integration eliminates subsequent assembly operations and reduces the potential for assembly errors, thereby maintaining reliability while simplifying manufacturing.

Inventive Principle:
Principle #10Preliminary action

3Volume of stationary object

If a compact arrangement of components is used in the base element, then the volume is reduced, but the device complexity increases

Engineering Contradiction:
ImprovevolumeVSAvoiddevice complexity
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The patent integrates multiple functional components (base plate, pedestals, bushings, securing elements) into a single compact base element. This merging allows for a space-efficient design that accommodates all necessary functions within a reduced volume while avoiding the complexity of arranging and assembling multiple separate compact components.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3208814B1Base element to carry an insulating column and a head of a current transformer
Publication Date: 2021.03.31 GENERAL ELECTRIC TECH GMBH
  • EP3208814B1 patent drawingFigure 1~3
  • EP3208814B1 patent drawingFigure 4

AI summary

The invention relates to a base element (4) for a current transformer (1), to carry an extremity of an insulating column (3) of the transformer which carries a head (2) of the transformer (1), this base element (4) comprising: - a plurality of electric epoxy resin bushings (21) carrying each a corresponding secondary lead (18) comprising each a portion extending out of the base and a portion extending in the base ; - a plurality of outer plugs (14) comprising each a portion extending out of the base and a portion extending in the base ; - a plurality of wires extending in the base, each wire connecting a secondary lead to a corresponding plug ; According to the invention, the portion of the secondary leads extending in the base, the portions of the plugs extending in the base and the wires are embedded in a block of cast material.