Power Line Fault Detection Using Wavelet Transient Monitoring
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Solution Overview
Problem
Conventional fault location systems in power transmission networks face challenges in accurately determining timestamps for traveling wave-based fault location due to errors in detecting fast transient signals, leading to inaccurate fault localization and increased memory and processing requirements.
Innovation Solution
A method involving signal decomposition into multiple frequency bands using wavelet filters, particularly Haar wavelets, to detect fast transients directly, allowing for real-time fault detection and reduced memory usage by capturing only relevant fault data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If level-based detection is used to detect faults by monitoring current exceeding a threshold, then fault detection capability is achieved, but memory requirements increase significantly to store large numbers of samples at high sampling rates
Solution Approach 1:
The patent extracts and monitors only the fast transient component of the signal separately from the main power frequency signal. By detecting faults based on this extracted transient component, the system can trigger recording only when necessary, dramatically reducing the amount of data that needs to be stored in memory while maintaining reliable fault detection capability.
Solution Approach 2:
The patent performs preliminary detection of fast transients continuously before fault occurrence. This preliminary action allows the system to identify potential faults early and trigger recording only when a transient is detected, rather than continuously recording all samples at high rate, thus reducing memory requirements while maintaining detection reliability.
2Measurement precision
If high sampling rates (300-500 kS/s or higher) are used to preserve fast transient information, then fault location accuracy is improved, but processing requirements and memory usage increase
Solution Approach 1:
The patent segments the signal processing into two distinct stages: continuous low-rate monitoring of fast transient components, and high-rate sampling only when transients are detected. This segmentation allows the system to maintain measurement precision for fault location while dramatically reducing overall processing requirements and memory usage by avoiding continuous high-rate sampling.
Solution Approach 2:
The patent dynamically changes the sampling rate parameter based on detected signal conditions. The system operates at low sampling rates during normal conditions and switches to high sampling rates only when fast transients are detected, thereby maintaining fault location accuracy when needed while reducing processing requirements during normal operation.
3Reliability
If continuous monitoring of the entire signal is performed to ensure no wavefronts are missed, then detection reliability is improved, but processing complexity and resource usage increase
Solution Approach 1:
The patent introduces fast transient detection as an intermediary mechanism that monitors the signal continuously at low complexity and triggers the more complex high-rate sampling process only when necessary. This intermediary approach ensures no wavefronts are missed while dramatically reducing overall processing complexity and resource usage compared to continuous full-signal monitoring.
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 and efficient fault localization by detecting fast transients before the main current surge, reducing memory and processing demands while ensuring precise timestamping for fault location.
Implementation Method 1
decomposing the signal into one or more frequency bands, and monitoring each frequency band for an indication of a fault on the power line
Data Source
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AI summary
There is disclosed herein a method for monitoring a power line, a device for performing the method, and a power transmission system comprising such a device. The method comprises obtaining a signal from the power line, comprising real-time information corresponding to the current and/or voltage on the power line at a monitoring location, decomposing the signal into one or more frequency bands, and monitoring each frequency band for an indication of a fault on the power line. According to such a method, fast transients arising from faults on the power can be rapidly identified, as part of a fault response trigger and the fault location can be determined without compromising accuracy of fault location, while allowing for a low usage of computational memory and/or processing.