Solid-State Circuit Interlocking for Breaker Failure Isolation

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Solution Overview

Problem

Solid state circuit breakers are prone to failure modes such as short circuits, which prevent them from opening and can lead to detrimental consequences for the circuit interruption system and the load.

Innovation Solution

A system where a first circuit breaker, upon detecting a failure mode, requests an upstream circuit breaker to interrupt current flowing to it, allowing its mechanical contacts to open safely after the current drops to a predetermined level, and communicates a clear request to resume normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical linkages and springs are used to maintain the open position of circuit interrupter contacts, then the contacts can be held open reliably, but the device complexity increases and the reliability decreases due to additional failure points

Engineering Contradiction:
Improvecontact open position reliabilityVSAvoidmechanical linkage complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical linkage and spring system with an electrical control system using solenoids and electrical signals. The controller electronically actuates the circuit interrupter to open or close contacts, eliminating complex mechanical components and their associated failure points while maintaining reliable contact positioning.

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

Solution Approach 2:

The patent introduces a controller as an intermediary between the sensing system and the circuit interrupter actuation. This controller processes sensor signals and coordinates the opening/closing of multiple circuit interrupters, simplifying the overall system architecture while improving reliability through electronic control rather than mechanical linkages.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple circuit interrupters are coordinated mechanically, then simultaneous opening can be achieved, but the device complexity and difficulty of coordination increase

Engineering Contradiction:
Improvesimultaneous contact openingVSAvoidcoordination mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical coordination mechanisms with an electronic control system. The controller receives signals from sensors and electronically coordinates the actuation of multiple circuit interrupters, achieving simultaneous opening without the complexity of mechanical synchronization linkages.

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

Solution Approach 2:

The controller serves multiple functions: it senses contact positions, coordinates the actuation of multiple circuit interrupters, and manages the sequential or simultaneous opening/closing operations. This multi-functional electronic controller simplifies the overall system compared to dedicated mechanical coordination mechanisms for each function.

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

3Stability of the object's composition

If wear-prone mechanical parts are used in the interlocking mechanism, then the circuit interrupter can maintain contact position, but the service life decreases due to wear

Engineering Contradiction:
Improvecontact position stabilityVSAvoidmechanism service life
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The patent replaces wear-prone mechanical interlocking parts with an electrical control system using solenoids and electronic signals. The controller electronically maintains contact positions and coordinates opening/closing operations without physical contact between moving parts, eliminating wear and extending service life while maintaining position stability.

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

4Measurement precision

If solid state sensors are used to detect contact position, then the measurement precision improves, but the device complexity increases

Engineering Contradiction:
Improvecontact position detection precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a controller as an intermediary that processes signals from solid-state sensors and coordinates the circuit interrupter operations. This centralized electronic processing simplifies the overall system architecture while maintaining the high measurement precision benefits of solid-state sensors, avoiding the need for complex distributed sensor systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4122068B1Solid state circuit interrupter with solid state interlocking mechanism
Publication Date: 2026.04.29 EATON INTELLIGENT POWER LTD
  • EP4122068B1 patent drawingFigure 1~2
  • EP4122068B1 patent drawingFigure 3
  • EP4122068B1 patent drawingFigure 4

AI summary

A system includes a first circuit breaker (10B-10N) comprising a first solid state switch (100), first mechanical contacts (500A), and a current sensor structured to sense current flowing through the first circuit breaker, and a second circuit breaker (10A) electrically coupled to the first circuit breaker (10B-10N) and being structured to interrupt current flowing to the first circuit breaker, wherein the first circuit breaker (10B-10N) is structured to transmit, to the second circuit breaker (10A), a request (SSI REQUEST SIGNAL) upon detecting a failure mode of the first solid state switch (100), and wherein the second circuit breaker (10A) is structured to interrupt current flowing to the first circuit breaker (10B-10N) in response to receiving the request, and the first circuit breaker (10B-10N) is further structured to open the first mechanical contacts (500A) when the current flowing through the first circuit breaker (10B-10N) drops to a predetermined level.