Fault Location Detection Using Fourier Derivative Analysis
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Solution Overview
Problem
Existing fault location and distance protection methods in power transmission networks are inaccurate due to decaying DC offset components in voltage and current measurements, leading to errors in impedance-based calculations and incorrect fault location determination.
Innovation Solution
An apparatus and method that determine fault location distance by calculating the derivative of current parameters using Fourier transformation, accounting for decaying DC components, and using line fault parameters to apply a specific line equation for accurate fault location and distance protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If impedance-based calculations are used for fault location determination, then the method is simple and easy to implement, but the accuracy deteriorates due to decaying DC offset components in voltage and current measurements
Solution Approach 1:
The patent extracts and eliminates the harmful decaying DC offset components from the voltage and current measurements before performing impedance-based fault location calculations. By removing these offset components through signal processing techniques, the accuracy of fault location determination is improved while maintaining the simplicity of the impedance-based approach.
Solution Approach 2:
The patent applies preliminary signal processing actions to the measured voltage and current signals before they are used in fault location calculations. This includes filtering out decaying DC components and preparing cleaned signals in advance, which ensures accurate fault location determination without complicating the overall method.
2Device complexity
If decaying DC offset components are not accounted for in measurements, then the calculation process is simple, but the fault location determination becomes inaccurate
Solution Approach 1:
The patent converts the harmful effect of decaying DC offset components into a beneficial process by using them as indicators to guide the signal processing. The presence of these offsets triggers specific filtering and processing steps that ultimately improve measurement accuracy, turning a source of error into a useful diagnostic feature.
Solution Approach 2:
The patent changes the parameters of the measured signals by applying filtering operations that remove decaying DC components. This parameter transformation modifies the signal characteristics to eliminate inaccuracies while preserving the essential fault information needed for reliable location determination.
3Ease of operation
If traditional Fourier transformation is applied directly to measured signals, then the processing is straightforward, but the results are erroneous due to DC offset contamination
Solution Approach 1:
The patent segments the signal processing into distinct stages: first removing decaying DC offset components, then applying Fourier transformation to the cleaned signals. This segmentation allows each processing step to be optimized independently, maintaining simplicity while improving precision by ensuring the Fourier analysis is performed on offset-free signals.
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
The solution provides accurate determination of fault location and distance protection, reducing errors and improving reliability by accounting for decaying DC components in voltage and current measurements, thus enhancing operational efficiency and reducing costs.
Implementation Method 1
determine a set of phasors {dot over (U)}P(n), İPR(n), İPX(n), and İP0(n) using a Fourier transformation of the derivative and of the remaining line fault parameters at the plurality of sample times
Data Source
AI summary
An apparatus for determining a fault location distance or distance protection in a multi-phase power transmission medium, configured to; determine a set of line fault parameters based on a measurement of voltage and current at a point of said power transmission medium and a fault type, the line fault parameters determined at a plurality of sample times determine a derivative with respect to time of a line fault parameters representative of an inductive part of measured faulty phase current; determine a set of phasors using a Fourier transformation of the derivative and of the remaining line fault parameters at the plurality of sample times and use said set of phasors to determine a fault location distance or distance projection distance along the power transmission medium; wherein, the determination of the fault location distance or the distance protection distance is based on the line equation;U.P=U.F+[R1I.PR+X1ω0I.PX]DF.