DC Busbar Edge Elements Suppress High-Frequency Short-Circuit Currents

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Solution Overview

Problem

Existing busbar systems for conducting electrical direct current struggle to effectively suppress high-frequency changing electrical short-circuit currents, which are common in DC circuit arrangements, due to their lack of insulation and high conductivity materials.

Innovation Solution

The use of edge elements with lower electrical conductivity, such as iron or stainless steel, positioned on the outer surfaces of busbars made of copper or aluminum, leverages the skin and proximity effects to redirect and suppress high-frequency currents, thereby reducing electrical short-circuit currents. This configuration includes multiple busbars stacked together, allowing for the displacement of high-frequency currents into edge elements, which increases electrical resistance and reduces short-circuit currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If busbars are made of high conductivity materials like copper or aluminum, then electrical conductivity is improved, but high-frequency changing electrical currents are not suppressed effectively

Engineering Contradiction:
Improveelectrical conductivityVSAvoidhigh-frequency changing electrical short-circuit currents
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The busbar system employs different materials with different electrical conductivities in specific locations: high conductivity copper or aluminum for the main busbar body to ensure good electrical conductivity, and low conductivity iron or steel edge elements at the edges to suppress high-frequency changing currents. This local differentiation of material properties resolves the contradiction between maintaining overall conductivity and suppressing harmful high-frequency currents.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The device combines multiple materials with different electrical properties - copper or aluminum busbars with iron or steel edge elements - to create a composite structure that simultaneously achieves high electrical conductivity in the main current path and suppression of high-frequency changing currents at the edges through the skin effect.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If edge elements with lower electrical conductivity are added to suppress high-frequency currents, then suppression of electrical short-circuit currents is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical short-circuit currentsVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple edge elements are combined into a single integrated component that spans across several busbars. This merged edge element design simplifies the overall structure by reducing the number of separate parts, while still maintaining the suppression function for high-frequency changing currents through the skin effect.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The edge elements serve multiple functions: they provide mechanical support for the busbar structure, establish defined electrical boundaries, and suppress high-frequency changing currents through the skin effect. This multi-functionality reduces the need for additional specialized components, thereby simplifying the overall device complexity.

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

The solution significantly reduces electrical short-circuit currents by increasing the electrical resistance for high-frequency changing currents, as demonstrated by simulations showing a voltage drop of about 75 V/m with copper busbars and iron edge elements, and further enhanced with stainless steel, effectively managing high-frequency components in DC circuit arrangements.

Implementation Method 1

the invention uses the skin effect in electrical conductors, through which high-frequency changing electrical currents are conducted within a conductor primarily near the outer surfaces of the conductor

Methodology Applied
Scientific EffectSkin effect: Skin Effect

Implementation Method 2

This refinement makes it possible to use not only the skin effect but also the proximity effect in order to displace high-frequency changing electrical currents in edge elements. The proximity effect is a current displacement between two adjacent electrical conductors under the influence of alternating currents.

Methodology Applied
Scientific EffectProximity effect:

Data Source

PatentEP3127202B1Device for conducting electrical direct current
Publication Date: 2018.02.28 SIEMENS AG
  • EP3127202B1 patent drawingFigure 1
  • EP3127202B1 patent drawingFigure 2

AI summary

The invention relates to a device (1) for conducting electrical direct current. Said device (1) comprises at least one bus bar (3) and at least one electrically conducting edge element (5) which is connected to the bus bar (3) in an electrically conducting manner and has a lower electrical conductivity than the bus bar (3), the edge element being arranged on a lateral outer face (7) of the bus bar (3) and extending along said bus bar (3).