DC Ring Bus Fault Isolation via Passive Protection

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Solution Overview

Problem

Existing DC power distribution systems face challenges in maintaining reliable power availability due to faults, which often result in power source removal and loss of power, especially for critical loads, and require effective fault isolation among multiple DC power sources.

Innovation Solution

The implementation of a DC ring bus architecture with semiconductor switches and passive components, including inductors and diodes, to isolate faults and limit current, ensuring continued power supply from other sources and reducing high-voltage stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple DC power sources are used to improve power availability, then power reliability is improved, but fault isolation complexity increases

Engineering Contradiction:
Improvepower availabilityVSAvoidfault isolation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The DC power distribution system is segmented into multiple independent zones, each protected by its own protection assembly. Each protection assembly independently manages fault isolation for its associated power source, preventing cascading failures and simplifying the overall fault isolation process while maintaining high power availability through multiple independent power paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Passive protection assemblies act as intermediaries between multiple DC power sources and the load. These assemblies include current-limiting inductors and protective components that automatically isolate faults without requiring complex active control systems, thereby maintaining power reliability while reducing fault isolation complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If passive protection assemblies with current limiting are used, then fault protection is improved, but device complexity increases

Engineering Contradiction:
Improvefault protectionVSAvoidprotection assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system employs passive protection assemblies containing inductors and other protective components that provide robust fault protection through simple, reliable, and inherently safe designs. These passive components offer overcurrent protection and fault isolation without requiring complex electronics or active control, achieving high fault protection with minimal complexity.

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

3Reliability

If inductors are used for current limiting, then fault current control is improved, but system cost increases

Engineering Contradiction:
Improvecurrent limiting capabilityVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system replaces complex active current control electronics with passive electromagnetic inductors that inherently limit fault current through their physical properties. This mechanical/electromagnetic approach provides reliable current limiting without requiring expensive microprocessors, sensors, or complex control circuits, thereby achieving effective current control at lower system cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enhances power availability and reliability by isolating faults, allowing other power sources to compensate for the lost power, reducing life-cycle costs and improving overall system reliability.

Implementation Method 1

a first branch including an inductor coupled between said first end and said second end of said first branch

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a second branch comprising a diode in series with a resistance coupled between said first end and said second end of said second branch

Methodology Applied
Scientific EffectDiode rectification: Diode

Data Source

PatentEP3101748B1Direct current power distribution and protection system
Publication Date: 2021.05.19 ABB (SCHWEIZ) AG
  • EP3101748B1 patent drawingFigure 1
  • EP3101748B1 patent drawingFigure 2
  • EP3101748B1 patent drawingFigure 3~4

AI summary

A direct current power (DC) distribution system (100) includes a plurality of DC power sources (102;400), a ring bus (108), a plurality of switch assemblies (104;210;300), and a plurality of passive protection assemblies (106;212). Each DC power source is coupled to the ring bus by a respective switch assembly and a respective passive protection assembly.