Concave Metal Flange Faraday Cage for Partial Discharge Detection

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Solution Overview

Problem

Existing partial discharge detection devices for gas-insulated high-voltage equipment face inefficiencies when external antennas are used, as their sensitivity is often insufficient due to distance from discharge sources, particularly in cases where internal installation is not possible.

Innovation Solution

A partial discharge detection device featuring a metal flange that forms a Faraday cage with the high-voltage equipment, optimizing the reflection chamber to standardize detection sensitivity across the spectrum, utilizing fractal architecture antennas with a concave or convex surface to enhance sensitivity and avoid resonance phenomena.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If external antennas are used for partial discharge detection, then installation flexibility is improved, but detection sensitivity deteriorates due to greater distance from discharge sources

Engineering Contradiction:
Improveinstallation flexibilityVSAvoiddetection sensitivity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent employs a concave metal flange structure that curves toward the antenna, creating a reflective surface that focuses electromagnetic signals. This curvature geometry redirects signals that would otherwise miss the antenna, effectively increasing detection sensitivity without requiring the antenna to be closer to the discharge source, thus resolving the contradiction between installation flexibility and detection sensitivity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent utilizes resonance phenomena by tuning the concave flange structure to specific frequencies. By designing the flange's dimensions and curvature to resonate at target detection frequencies, the system amplifies weak partial discharge signals, thereby improving detection sensitivity while maintaining external antenna installation flexibility.

Inventive Principle:
Principle #18Mechanical vibration

2Ease of manufacture

If conventional flat flange structures are used, then manufacturing simplicity is maintained, but detection sensitivity is insufficient due to poor signal reflection and resonance issues

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddetection sensitivity
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from a flat flange to a concave flange structure. While this adds some manufacturing complexity, the curved surface provides superior signal reflection properties and enables resonance tuning. The concave geometry naturally focuses electromagnetic waves toward the antenna, significantly improving detection sensitivity without requiring complex multi-component assemblies, thus achieving a practical balance between manufacturability and performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent optimizes specific parameters of the concave flange, including its curvature radius, depth, and dimensional proportions, to achieve desired resonance characteristics and signal reflection patterns. By carefully selecting these geometric parameters, the system achieves high detection sensitivity while maintaining reasonable manufacturing simplicity through single-piece fabrication methods.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the antenna is placed closer to the equipment window, then detection sensitivity improves, but resonance phenomena occur that disrupt the detection spectrum

Engineering Contradiction:
Improvedetection sensitivityVSAvoidresonance phenomena
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The concave flange structure acts as a signal focusing element that redirects electromagnetic waves onto the antenna from various angles and distances. This curvature allows the antenna to be positioned at an optimal distance from the window while still capturing enhanced signals, avoiding the harmful resonance effects that occur when antennas are placed too close, thus resolving the contradiction between sensitivity improvement and resonance avoidance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The concave metal flange serves as an intermediary structure between the equipment window and the antenna. It captures and redirects electromagnetic signals, mediating the interaction between the distant antenna and the partial discharge sources. This intermediary function allows the system to achieve high sensitivity without direct proximity, thereby avoiding resonance disruptions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution provides excellent detection performance with high sensitivity, allowing for effective partial discharge detection even in restricted spaces and compliance with sensitivity recommendations, such as TGN21, while minimizing the number of sensors and costs.

Implementation Method 1

a metal flange which is made in electrical contact with a metal wall of the high-voltage equipment and contributes to forming, in combination with said wall, a Faraday cage which electrically isolates the antenna from the outside of the high-voltage equipment

Methodology Applied
Scientific EffectFaraday cage: Faraday Cage

Implementation Method 2

The concavity of the metal flange induces a height variation between the flange and the antenna. This height variation advantageously optimizes the Faraday cage's reflective enclosure. Resonance phenomena that could occur in the detection spectrum can then be avoided

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3175249B1Device for detecting a partial discharge from high-voltage gas-insulated equipment
Publication Date: 2020.04.08 GENERAL ELECTRIC TECH GMBH
  • EP3175249B1 patent drawingFigure 1~2
  • EP3175249B1 patent drawingFigure 3A~3B
  • EP3175249B1 patent drawingFigure 4A~4B

AI summary

The invention relates to a device for detecting a partial discharge from high-voltage gas-insulated equipment, the device including at least one antenna (A) arranged outside the high-voltage gas-insulated equipment and opposite a hatch (H) of the high-voltage gas-insulated equipment, characterized in that it also includes a metal flange (B) which is placed in electrical contact with a metal wall (1a, 1b) of the high-voltage equipment, and which forms, together with said wall, a Faraday cage that electrically insulates the antenna from the outside of the high-voltage equipment, the metal flange (B) having a concave wall opposite the hatch (H).