Online Cable Fault Detection Using Wavelet Transform
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Solution Overview
Problem
Existing methods for detecting faults in underground high-voltage cables require offline detection, necessitating complete disconnection and resulting in prolonged fault location and repair times.
Innovation Solution
A system and method for online fault detection in cables using current transforming units, wavelet transforms to extract high-frequency detail signals, and signal filtering to generate and compare filtering signals, allowing for real-time identification of faults and their locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offline detection methods (Murray loop method, TDR, pin pointing method) are used to detect fault location, then measurement precision can be achieved, but loss of time increases significantly due to complete disconnection requirement
Solution Approach 1:
The patent replaces traditional mechanical/electrical disconnection-based detection methods with an optical fiber-based detection system. The optical fiber communicates fault location information to the control center without requiring physical disconnection of the cable, enabling online detection while maintaining measurement precision through optical signal analysis.
Solution Approach 2:
The patent introduces an optical fiber as an intermediary medium between the cable fault detection point and the control center. This optical fiber transmits fault location data without interfering with the cable's electrical operation, allowing precise fault location while avoiding the time loss associated with complete disconnection for traditional methods.
2Measurement precision
If complete disconnection of the cable is performed for fault detection, then measurement precision is improved, but productivity decreases due to prolonged detection and repair time
Solution Approach 1:
The patent substitutes the mechanical disconnection process with optical signal-based non-contact detection. The optical fiber system transmits fault location information without requiring cable disconnection, thereby maintaining cable operational status and improving productivity while preserving measurement precision through accurate optical signal analysis.
Solution Approach 2:
The patent enables continuous monitoring and fault detection without interrupting cable operation. The optical fiber system allows the cable to remain connected and operational while fault location is determined through optical signal transmission, eliminating the productivity loss associated with complete disconnection and enabling rapid repair operations.
3Device complexity
If traditional offline detection methods are used, then device complexity remains relatively simple, but loss of time increases due to complete system separation requirement
Solution Approach 1:
The patent introduces an optical fiber as a simple intermediary component that enables online fault detection without complex electrical disconnection procedures. This optical fiber-based system maintains relatively simple device complexity while dramatically reducing fault detection time by eliminating the need for complete system separation required by traditional methods.
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 rapid and accurate online detection of fault locations in cables, reducing the time and cost associated with fault repair by filtering out noise and identifying reflected waves within the cable.
Implementation Method 1
detecting a first approximation signal and a first detail signal from the original signal of fault current through wavelet transform
Implementation Method 2
a current transforming unit, connected to the cable and receiving the fault current and detecting an original signal of fault current
Data Source
AI summary
A system for detecting a location of fault in a cable includes a cable transmitting a fault current, a current transforming unit connected to the cable and receiving the fault current and detecting an original signal of fault current, a detecting unit detecting a first detail signal and a second detail signal from the original signal of fault current, where both signals are detail components in a high frequency band, a comparing unit comparing the first detail signal with a preset reference value and determining a fault in the cable, and a signal filtering unit generating a first filtering signal and a second filtering signal by use of the first detail signal and the second detail signal and outputting a fault detection signal based on a result of comparing both signals.