Grounded Condenser Core Foils for Transient Heating Control

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Solution Overview

Problem

Large diameter condenser cores face issues with potential differences and heating at the joint of overlapping capacitive layers due to the lack of available foils, leading to inefficiencies and performance degradation during transient events.

Innovation Solution

The outermost capacitive layers are grounded on both sides via separate grounding arrangements, providing an additional path for current to flow and reducing resistive heating and potential differences, thereby stabilizing the electrical potential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional condenser core with plastic encapsulation is used, then manufacturing is simplified and electrical insulation is provided, but static electricity accumulates on the surface causing electromagnetic interference and signal noise

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidelectromagnetic interference
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies grounding foils connected to ground potential to dissipate the static electricity that accumulates on the plastic encapsulation surface. This converts the harmful static charge into a controlled electrical path to ground, eliminating electromagnetic interference while preserving the benefits of plastic encapsulation including manufacturing simplicity and electrical insulation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The grounding foils act as an intermediary element between the plastic encapsulation and ground. These conductive foils are positioned against the plastic surface and connected to ground potential, serving as a mediator that safely dissipates static charges without requiring changes to the plastic material itself or the overall encapsulation structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If aluminum foil is used for electromagnetic shielding, then EMI protection is provided, but the foil detaches during assembly and handling due to lack of adhesion

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidfoil attachment stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent uses thin grounding foils that are intentionally designed to be temporary or sacrificial in nature. These foils are applied to the plastic surface, serve their grounding function during assembly and operation, and can be removed or degraded without affecting the core condenser structure. This approach prioritizes functional effectiveness over long-term permanence.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent employs thin flexible foils rather than rigid shielding materials. These thin films can conform to the plastic encapsulation surface and are easier to handle during assembly. The flexibility allows the foils to maintain contact with the surface while being less prone to damage or detachment compared to more rigid aluminum foil alternatives.

Inventive Principle:
Principle #30Flexible shells and thin films

3Device complexity

If static electricity is allowed to accumulate on the condenser core, then no additional grounding components are needed, but electromagnetic interference degrades signal quality in wireless communication systems

Engineering Contradiction:
Improvecomponent countVSAvoidsignal quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The grounding foils serve multiple functions simultaneously: they provide electromagnetic shielding, dissipate static electricity, and can act as an additional grounding path. This multi-functionality allows the system to address EMI and signal quality issues without adding significant complexity, as the same grounding structure performs multiple protective roles.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This solution effectively mitigates resistive heating and potential differences at the foil joints, enhancing the performance and reliability of condenser cores during transient events.

Implementation Method 1

a first capacitive layer including a first conductive foil, a second conductive foil, and a dielectric material between the first conductive foil and the second conductive foil

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

at least one grounding foil made of a conductive material and arranged to be in contact with the plastic encapsulation and at ground potential

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4062437B1Condenser core with conductive sheets earthed in a cable feedthrough or termination
Publication Date: 2026.05.06 HITACHI ENERGY LTD
  • EP4062437B1 patent drawingFigure 1~3

AI summary

The present disclosure relates to a condenser core configured for surrounding an electrical conductor. The condenser core comprises an insulation material and a plurality of electrically conducting capacitive layers (5) for modifying electrical fields formed by a current flowing in the electrical conductor. At least one of the electrically conducting capacitive layers comprises a first foil (5a) and a second foil (5b). Each of the first and second foils of an outermost capacitive layer is connected with a grounding arrangement (10a, 10b) for grounding the foils.