Submarine Cable Fault Detection with Dynamic Reference Reset

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Solution Overview

Problem

Existing submarine cable systems struggle to detect multiple faults occurring in optical transmission paths, as alarms for initial faults overshadow subsequent faults due to unchanged reference levels and thresholds.

Innovation Solution

A fault detection apparatus and method that adjusts reference levels and thresholds dynamically based on previous fault occurrences, allowing for the detection of multiple faults by setting new reference levels and thresholds after each fault event.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed reference level and threshold value are used for fault detection, then the detection system is simple and stable, but subsequent faults cannot be detected after an initial fault occurs

Engineering Contradiction:
Improvefault detection capabilityVSAvoidreference level adjustment mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from a static reference level to a dynamic reference level that automatically updates after fault detection. The control unit changes the reference level based on the detected fault condition, enabling the system to adapt to changing operational states and detect multiple faults sequentially.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using the fault detection result to modify the reference level and threshold values. The control unit receives feedback from the fault detection process and adjusts the parameters accordingly, creating a closed-loop system that can detect multiple faults.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the reference level is updated after each fault, then multiple faults can be detected accurately, but the system complexity increases

Engineering Contradiction:
Improvefault detection precisionVSAvoidcontrol mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-service by automatically updating the reference level and threshold values without external intervention. The control unit autonomously processes the fault detection results and adjusts the parameters, eliminating the need for manual configuration and reducing operational complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies parameter changes by modifying the reference level and threshold values as system parameters in response to detected faults. This allows the detection system to adapt its sensitivity and reference criteria dynamically, improving measurement precision for subsequent faults.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a single threshold value is used for all fault conditions, then the system is simple to operate, but it cannot distinguish between different fault levels

Engineering Contradiction:
Improvefault detection operationVSAvoidfault level information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent applies segmentation by dividing the fault detection into multiple stages with different threshold values. Instead of using a single threshold for all faults, the system segments the detection process into first fault detection (using initial threshold) and subsequent fault detection (using updated threshold), allowing differentiation between fault levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the threshold value based on the detection stage and fault condition. The control unit changes the threshold parameter from an initial value to an updated value after detecting a fault, enabling the system to distinguish between different fault levels while maintaining ease of operation through automated adjustment.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4109843B1Fault detection apparatus, fault detection method, and submarine cable system
Publication Date: 2025.11.19 NEC CORP
  • EP4109843B1 patent drawingFigure 1
  • EP4109843B1 patent drawingFigure 2
  • EP4109843B1 patent drawingFigure 3

AI summary

In order to provide a technology for detecting a plurality of faults that occurred in sections through which optical signals are transferred, this fault detection apparatus is provided with: a transmitter that transmits a first optical signal through an optical transmission line; a receiver that receives, in response to the transmission of the first optical signal, a second optical signal from the optical transmission line, and measures the reception level of the second optical signal; and a control unit that specifies a section where the second optical signal corresponding to the first optical signal was generated, calculates an optical level corresponding to a loss in said section on the basis of the reception level, determines that a first fault has occurred in the section when the optical level in the section has changed from a first reference level by a first threshold or more, sets a second reference level and a second threshold after occurrence of the first fault, and determines that a second fault has occurred in the section when the optical level has changed from the second reference level by the second threshold or more.