High-Voltage Cable Shield Fault Localization Using Synchronized Timing

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Solution Overview

Problem

Current methods for locating short circuits between the conductor and the electrically conductive shield of high-voltage power cables are inaccurate and cannot predict the failure time or location with certainty, especially during operation, and offline fault location methods require cable disconnection, making them inefficient.

Innovation Solution

A system and method using synchronized measuring devices to detect and analyze current patterns in the electrically conductive shield and ground lines, employing high sampling rates and data analysis, including AI or machine learning, to determine the time and location of short circuits, even during operation, by accounting for impedance and propagation speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If offline fault location methods are used to locate short circuits, then measurement precision is improved, but productivity deteriorates because cable disconnection is required

Engineering Contradiction:
Improvefault location precisionVSAvoidenergy transmission continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs preliminary setup by installing synchronized measuring devices and establishing baseline current patterns before faults occur. This allows the system to be ready for immediate fault detection without requiring cable disconnection, thus maintaining productivity while enabling precise fault location when needed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical cable disconnection with electrical signal analysis. Instead of physically accessing the cable (mechanical approach), the system uses current pattern analysis and signal processing (electrical approach) to locate faults while the cable remains connected and energized, thereby maintaining energy transmission continuity

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

2Measurement precision

If conventional current measurement methods are used, then device complexity is reduced, but measurement precision deteriorates due to inability to detect fault location accurately

Engineering Contradiction:
Improveshort circuit localization accuracyVSAvoidmeasuring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the cable into multiple segments by placing measuring devices at different locations. Each measuring device independently monitors its local segment, and the combination of measurements from multiple segments enables precise fault localization through comparison and triangulation, improving measurement precision while distributing system complexity across multiple simple units

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system continuously monitors current patterns and provides feedback when deviations from normal operation are detected. This feedback mechanism triggers detailed analysis and fault localization only when necessary, improving measurement precision for actual faults while minimizing the operational impact of the monitoring system during normal conditions

Inventive Principle:
Principle #23Feedback

3Measurement precision

If high sampling rates are used for current detection, then measurement precision is improved, but use of energy increases

Engineering Contradiction:
Improvefault detection accuracyVSAvoidenergy consumption of measuring devices
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses periodic sampling of current patterns at high rates only during fault detection events rather than continuous high-rate sampling. During normal operation, sampling occurs at lower rates, reducing energy consumption. When faults are detected, the system temporarily increases sampling rate to capture detailed fault characteristics, achieving high measurement precision only when needed

Inventive Principle:
Principle #19Periodic action

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 approach allows for precise localization of short circuits during operation with high accuracy, improving upon existing methods by enabling continuous energy transmission and reducing excavation costs by accurately identifying the faulty segment without disconnecting the cable.

Implementation Method 1

a measuring device for detecting an electrical current flowing in the electrically conductive shield and/or an electrical current flowing in a ground line connecting the electrically conductive shield and ground and the time of its occurrence

Methodology Applied
Scientific EffectElectrical current detection: Conduction (electrical)

Implementation Method 2

providing at least two measuring devices arranged on the high-voltage cable at a known distance from one another or from the ends of the high-voltage cable, which have synchronized timers

Methodology Applied
Scientific EffectTime delay measurement: Time of Flight

Implementation Method 3

The analysis unit supplies a calculation unit with at least the value of the timer, which was determined over time after the occurrence of a current exceeding a threshold value

Methodology Applied
Scientific EffectSignal propagation: Electromagnetic Induction

Data Source

PatentEP3786652B1Method and system for locating a short-circuit between a conductor and an electrically conductive screen surrounding said conductor
Publication Date: 2023.12.06 NEXANS SA
  • EP3786652B1 patent drawingFigure 1~6
  • EP3786652B1 patent drawingFigure 3a~3d
  • EP3786652B1 patent drawingFigure 4a~4d

AI summary

A method for locating a short circuit between a conductor and an electrically conductive shield of a high-voltage cable comprises providing at least two measuring devices arranged at a known distance from each other on the high-voltage cable. These measuring devices include synchronized timers and a measuring device for detecting an electric current flowing in the shield and/or a grounding conductor connecting the shield and earth. The measuring device transmits pairs of current measurements and corresponding timer values ​​to an analysis unit. Upon the occurrence of a current exceeding a threshold value and/or a current profile fulfilling certain specifications over time, the analysis unit provides a processing unit with the corresponding timer values ​​and information about the measurement location where the first effects of the short circuit occurred.The calculation unit calculates the location of a short circuit from the known distance between the measuring devices and a difference between the values ​​of the synchronized timers.