Movable Bridge Current Controlling Device for Fault Limiting

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Solution Overview

Problem

Existing current controlling devices in electrical power systems are bulky and require extensive servicing and replacement after faults, necessitating a more compact and efficient solution for managing fault currents.

Innovation Solution

A device that controls current by manipulating magnetic flux and impedance using a magnetically permeable core with a movable bridge element, allowing for faster activation and reduced size, and can function as a fault current limiter, differential mode filter, or variable inductor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a parallel circuit is used to divert fault current, then fault current limiting is achieved, but device size increases and more parts require replacement after fault

Engineering Contradiction:
Improvefault current limiting capabilityVSAvoiddevice size and parts quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the fault current limiting function from a complex parallel circuit architecture and implements it through a single series-connected device with a movable bridge element. This eliminates the need for bulky parallel circuits while maintaining the fault current limiting capability through magnetic flux manipulation in the core.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The device provides multiple functions including fault current limiting, differential mode filtering, and variable inductance control through a single integrated structure. The movable bridge element can be positioned to achieve different operational modes, eliminating the need for separate devices for each function and reducing overall device complexity.

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

2Reliability

If traditional fault current limiters are used, then fault protection is provided, but activation time is delayed and size is large

Engineering Contradiction:
Improvefault protection capabilityVSAvoidactivation speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The movable bridge element is pre-positioned in the first position during normal operation, establishing the magnetic flux path in advance. When a fault occurs, the controller can immediately move the bridge element to the second position, achieving rapid activation without delay for magnetic field buildup or other preparatory processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional electromagnetic or superconducting mechanisms with a mechanically actuated movable bridge element that directly controls magnetic flux path. This mechanical system provides faster and more reliable activation compared to traditional fault current limiters that rely on electromagnetic field changes or superconducting transitions.

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

The solution provides a compact, efficient, and versatile means to manage fault currents, reducing the duration of excessive current exposure and eliminating the need for external power sources, while enabling faster activation and reduced maintenance.

Implementation Method 1

controlling an amount of current within a power distribution network by manipulating the amount of magnetic flux in the device

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

winding a plurality of coils about a magnetically permeable core and by providing the device with a magnetically permeable bridge element

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Implementation Method 3

winding a plurality of coils about a magnetically permeable core... net magnetic flux generated in the core by alternating currents in each coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3591674B1Current controlling device
Publication Date: 2021.05.05 ROLLS ROYCE PLC
  • EP3591674B1 patent drawingFigure 1
  • EP3591674B1 patent drawingFigure 2
  • EP3591674B1 patent drawingFigure 3

AI summary

There is described a device for controlling an amount of current within a power distribution network by manipulating the amount of magnetic flux in the device and thus the impedance experienced by the power distribution network across the device. This is achieved by winding a plurality of coils about a magnetically permeable core and by providing the device with a magnetically permeable bridge element that is movable between a fully-open position at which the net magnetic flux generated in the core by alternating currents in each coil is zero, and a fully-closed position at which a net magnetic flux is present in the core.