Fault Point Voltage Calculation for Power Line Fault Identification
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Solution Overview
Problem
Current methods for identifying fault types on multiple-circuit power lines are ineffective due to electromagnetic coupling effects and inability to distinguish between transient and permanent faults, leading to inaccurate judgments and limited applicability.
Innovation Solution
A criterion that calculates fault point voltage using terminal voltage and fault locations, incorporating transition resistance and extinction time of secondary arcs, to provide adaptive reclosure schemes and accurately differentiate between transient and permanent faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional terminal voltage magnitude criterion is used for single line, then the method is simple to implement, but it is easily affected by electromagnetic coupling voltage and gets wrong judgments for permanent fault with transition resistance
Solution Approach 1:
The patent changes the parameter used for fault identification from terminal voltage magnitude to fault point voltage magnitude. By calculating the voltage at the actual fault location rather than using terminal voltage, the criterion avoids the influence of electromagnetic coupling voltage while maintaining implementation feasibility through voltage calculation based on terminal measurements.
Solution Approach 2:
The patent introduces fault point voltage calculation as an intermediary step between terminal voltage measurement and fault type judgment. This intermediary calculation eliminates the direct influence of electromagnetic coupling voltage on the identification criterion while preserving the essential information needed for accurate fault classification.
2Adaptability or versatility
If traditional voltage magnitude criterion is used for multiple circuit lines, then the criterion can be applied to single line, but it cannot accurately distinguish transient faults from permanent faults due to great coupling effect of inductance and capacitance
Solution Approach 1:
The patent changes from using terminal voltage magnitude to using fault point voltage magnitude for fault identification. This parameter change enables accurate distinction between transient and permanent faults in multiple circuit lines by eliminating the distorting effect of electromagnetic coupling, while maintaining backward compatibility with single line applications.
Solution Approach 2:
The patent segments the fault identification process into distinct steps: calculating fault point voltage based on terminal voltage and fault location, then comparing this calculated value against threshold criteria. This segmentation allows the criterion to handle both single line and multiple circuit line scenarios accurately by isolating the fault point voltage calculation from the coupling effects.
3Reliability
If floating threshold based on fault point voltage is used for permanent fault with maximum transition resistance, then the correctness of judgments is ensured, but the calculation complexity increases
Solution Approach 1:
The patent implements a dynamic threshold setting mechanism where the threshold value adapts based on the calculated fault point voltage and fault location. This dynamic approach ensures correct judgment for permanent faults with transition resistance by adjusting the threshold to match the actual fault conditions, rather than using fixed threshold values.
Solution Approach 2:
The patent changes the threshold parameter from a fixed value to a floating value that varies with fault point voltage and location. This parameter change enables the criterion to maintain high reliability across different fault scenarios while the computational complexity is managed through efficient voltage calculation algorithms.
Data Source
AI summary
A method for identifying the type of faults occurred on a power line, characterized in that it comprises: calculating a fault point voltage on fault points based on terminal voltage and fault locations of the power line; adopting the fault point voltage corresponding to a maximum transition resistance as a setting value; comparing the fault point voltage on fault points with the setting value; and identifying the type of fault as a permanent type or a transient type based on the result of the comparison.