Optical Repeater Power Cable for Long-Haul Fault Detection

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Solution Overview

Problem

Existing power cable detection systems, such as those described in Patent Literature 1 and 2, suffer from attenuation of measurement light and backscattered light, limiting the detection accuracy and length of power cables, and require multiple laser devices and electric supply lines, making them unsuitable for long-haul power lines.

Innovation Solution

A power cable configuration using optical fibers for sensing and backscattered light, with optical amplifier repeaters that amplify these signals without laser devices, allowing detection of anomalies in long-haul power lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If optical fibers are used to transmit sensing light and backscattered light over long distances, then the detection capability for long-haul power lines is improved, but the light signals attenuate and detection accuracy deteriorates

Engineering Contradiction:
Improvedetection length of power cableVSAvoidattenuation of sensing light and backscattered light
Core Design Contradiction:
Length of stationary objectVSLoss of energy

Solution Approach 1:

The patent introduces optical amplifier repeaters as intermediary devices along the optical fiber path. These repeaters contain Erbium-doped optical fibers that amplify the sensing light and backscattered light signals using pump light, thereby compensating for signal attenuation over long distances and enabling detection of anomalies in long-haul power lines while maintaining detection accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements continuous signal amplification by placing optical amplifier repeaters at intervals along the optical fiber. This ensures that the sensing light and backscattered light signals are continuously boosted throughout their transmission path, maintaining sufficient signal strength for accurate anomaly detection across extended cable lengths

Inventive Principle:
Principle #20Continuity of useful action

2Measurement precision

If optical amplifier repeaters with Erbium-doped optical fibers are used to amplify sensing light and backscattered light, then detection accuracy in long-haul power cables is improved, but the device complexity increases

Engineering Contradiction:
Improveanomaly detection accuracyVSAvoidcomplexity of optical fiber system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the optical amplifier repeaters serve multiple functions: they amplify the sensing light forward-propagating through the optical fiber, and simultaneously amplify the backscattered light returning to the detection system. This multi-functionality improves anomaly detection accuracy in long-haul cables while avoiding the need for separate amplification systems for each direction

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

Solution Approach 2:

The optical amplifier repeaters use Erbium-doped optical fibers that can be pumped to achieve population inversion and light amplification through the Erbium ions' optical properties. This self-contained amplification mechanism within the repeater units provides the necessary signal boosting without requiring external complex control systems

Inventive Principle:
Principle #25Self-service

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

Enables accurate detection of anomalies in long-haul power cables by amplifying sensing and backscattered light signals, eliminating the need for laser devices and electric supply lines, thus enhancing detection capabilities.

Implementation Method 1

an optical fiber that transmits first excitation light for amplifying the sensing light; an optical amplifier repeater that amplifies the sensing light with the first excitation light

Methodology Applied
Scientific EffectStimulated emission:

Implementation Method 2

an optical fiber that transmits second excitation light for amplifying the backscattered light; an optical amplifier repeater that amplifies the backscattered light with the second excitation light

Methodology Applied
Scientific EffectStimulated emission:

Implementation Method 3

a second optical fiber that transmits backscattered light of the sensing light

Methodology Applied
Scientific EffectBrillouin scattering: Brillouin Scattering

Data Source

PatentEP4704118A1Power cable, power line, power cable abnormal point detection system, and power cable abnormal point detection method
Publication Date: 2026.03.04 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP4704118A1 patent drawingFigure 1~2
  • EP4704118A1 patent drawingFigure 3
  • EP4704118A1 patent drawingFigure 4

AI summary

A power cable includes: a cable body including a conductor, an insulating layer, a semiconductive layer, and a sheath; a first optical fiber that transmits sensing light; a second optical fiber that transmits backscattered light of the sensing light; an optical fiber that transmits first excitation light for amplifying the sensing light; an optical fiber that transmits second excitation light for amplifying the backscattered light; and at least one optical amplifier repeater that amplifies the sensing light with the first excitation light, and amplifies the backscattered light with the second excitation light.