HVDC Corona Shield Barrier for Safe Access

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Solution Overview

Problem

High voltage assemblies in HVDC converters pose a risk of electric shock during maintenance due to the need to verify the absence of voltage, which is time-consuming and hazardous, especially when dealing with multiple assemblies.

Innovation Solution

A corona shield with a deformable, electrically insulating or conducting barrier member that occludes the frame aperture to prevent bodily ingress, allowing for safe access while maintaining ventilation and electrostatic performance, and is moveable for easy access to the high voltage assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a barrier member is added to occlude the frame aperture to prevent bodily ingress, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The corona shield is segmented into two distinct components: a rigid peripheral frame and a separate deformable barrier member. This segmentation allows the barrier member to be independently designed with specific safety features while maintaining the structural integrity of the frame, thereby improving safety without significantly complicating the overall device.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The barrier member is designed to be deformable rather than rigid, allowing it to flex and deform to a predetermined extent when subjected to external forces. This dynamic characteristic enables the barrier to absorb impact forces while maintaining its protective function, improving safety without requiring additional complex mechanical structures.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the barrier member is made rigid to prevent deformation, then structural stability is improved, but the ability to absorb impact forces deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidimpact resistance
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The barrier member's material parameters are specifically selected to achieve an optimal balance between rigidity and deformability. By controlling the degree of deformation to a predetermined extent, the barrier maintains structural stability while effectively absorbing impact forces through controlled deformation, resolving the contradiction between stability and impact resistance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the barrier member is made from electrically insulating material to provide electrical protection, then electrical safety is improved, but electrostatic performance deteriorates

Engineering Contradiction:
Improveelectrical safetyVSAvoidelectrostatic performance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Different regions of the corona shield system have different electrical properties: the peripheral frame maintains its electrostatic function with conductive properties, while the barrier member uses insulating material for electrical protection. This local differentiation of material properties allows each component to fulfill its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The barrier member acts as an intermediary between the external environment and the high voltage assembly. By using electrically insulating material, it provides electrical protection while the peripheral frame continues to maintain the electrostatic field, thus mediating between electrical safety requirements and electrostatic performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If the barrier member is made solid to prevent bodily ingress, then safety is improved, but ventilation and visibility deteriorate

Engineering Contradiction:
ImprovesafetyVSAvoidventilation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The barrier member incorporates a perforated structure with numerous small openings. These perforations allow air to pass through, maintaining ventilation, while the overall structure remains sufficiently dense to prevent bodily ingress. The perforated design thus reconciles the contradiction between safety and ventilation by using a porous configuration.

Inventive Principle:
Principle #31Porous materials

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 corona shield significantly reduces the time and risk associated with accessing high voltage assemblies by preventing direct contact with the assemblies, ensuring safety and efficiency during maintenance, particularly in tiered arrays of HVDC converters.

Implementation Method 1

the barrier member is able to deform relative to the frame aperture to only a predetermined extent which is not beyond the frame aperture

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3394940B1Improvements in or relating to corona shields
Publication Date: 2019.10.09 GENERAL ELECTRIC TECH GMBH
  • EP3394940B1 patent drawingFigure 1
  • EP3394940B1 patent drawingFigure 2
  • EP3394940B1 patent drawingFigure 3

AI summary

In the field of voltage assemblies with a charge storage capability for use in high voltage direct current (HVDC) converters there is provided a corona shield(10). The corona shield (10) comprises a peripheral frame(12) which is formed from one or more frame members(14)and within which lies a frame aperture(18). The corona shield (10) also includes a barrier member(20) that is fixedly secured to the peripheral frame(12). The barrier member(20) extends across and occludes the frame aperture(18)to inhibit bodily ingress through the frame aperture(18).