Broken Conductor Detection Using Voltage Asymmetry
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Solution Overview
Problem
Existing broken conductor detection methods in distribution systems, such as the negative phase sequence current detection method, are inadequate as they fail to detect broken conductors in all situations and cannot locate the broken conductor, especially when the conductor is on a highly resistive surface or at the end of the distribution system.
Innovation Solution
A method and apparatus that measure voltage and current values at nodes in the distribution system, using calculated thresholds based on mean values of other feeders, to generate signals indicating broken conductors, allowing for improved detection and localization of broken conductors by identifying asymmetric voltage patterns and reduced currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative phase sequence current detection method is used to detect broken conductors, then the detection can be performed using current measurements, but the method fails to detect broken conductors when no current flows through the feeder (e.g., conductor on highly resistive surface or at end of distribution system)
Solution Approach 1:
The patent changes the detection parameter from current-based (negative phase sequence current) to voltage-based (phase voltage asymmetry). By measuring voltage instead of current, the system can detect broken conductors in all situations including those where no current flows, such as conductors on highly resistive surfaces or at the end of distribution systems. This parameter change resolves the contradiction by maintaining detection reliability across all broken conductor scenarios.
2Measurement precision
If the negative phase sequence current detection method is used, then current flow conditions can be utilized for detection, but the method cannot locate the broken conductor of the distribution feeder
Solution Approach 1:
The patent adds the dimension of location identification by comparing voltage measurements from multiple nodes along the distribution feeder. By detecting which specific node exhibits voltage asymmetry, the system not only detects the broken conductor but also identifies its location, thereby recovering the location information that was previously lost.
3Reliability
If voltage and current measurements are taken at all nodes to improve detection accuracy, then the detection coverage is enhanced, but the system complexity and measurement requirements increase
Solution Approach 1:
The patent segments the distribution system into multiple nodes and applies voltage asymmetry detection at each node independently. This segmentation allows the system to maintain high detection reliability across the entire network while using simple, standardized measurement procedures at each segment, avoiding the need for complex centralized measurement systems.
Data Source
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AI summary
A broken conductor detection method and apparatus. The apparatus includes: a measurement module(502), used to measure, at a node(120-1,120-2,120-3) of a distribution system(10), a voltage value of each distribution feeder(110-1,110-2,110-3) of the distribution system(10); a check module(504), used to check whether the measured voltage value of each distribution feeder T(110-1,110-2,110-3) of the distribution system(10) is less than a voltage threshold used for the distribution feeder T(110-1,110-2,110-3), the voltage threshold used for the distribution feeder T(110-1,110-2,110-3) being calculated based on a mean value of measured voltage values of other distribution feeders(110-1,110-2,110-3) in the distribution system(10); a generating module(506), used to: if a checking result indicates that a measured voltage value of a distribution feeder(110-1,110-2,110-3) of the distribution system(10) is less than the voltage threshold used for said distribution feeder(110-1,110-2,110-3), generate a signal indicating that said distribution feeder(110-1,110-2,110-3) of the distribution system(10) has a broken conductor; and a sending module(508), used to send the generated signal. The method and apparatus can improve the broken conductor detection for a distribution feeder(110-1,110-2,110-3) in a distribution system(10).