Voltage Derivative Broken Conductor Detection
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Solution Overview
Problem
Electric power delivery systems face challenges in detecting broken conductors, which can pose risks due to mechanical and thermal stresses, leading to potential falls and contact with ground or people, necessitating a system to monitor voltage changes and de-energize conductors before contact.
Innovation Solution
A system utilizing intelligent electronic devices (IEDs) and a central controller to detect broken conductors by analyzing the rate of change of voltage and zero-sequence voltage, with PMUs obtaining phasor data to determine the location and trigger circuit breakers for de-energization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional monitoring methods are used to detect broken conductors, then the system structure remains simple, but the detection reliability and speed are insufficient
Solution Approach 1:
The patent introduces an intermediary processing layer that analyzes the relationship between zero-sequence voltage and its derivative. This intermediary analysis mechanism enables reliable broken conductor detection by examining the characteristic patterns in voltage changes, rather than relying on simple threshold comparisons. The intermediary processing extracts meaningful detection signals from the complex voltage data.
Solution Approach 2:
The patent replaces conventional mechanical or simple electrical monitoring methods with a sophisticated signal processing approach using derivative calculations. By substituting the detection mechanism with mathematical analysis of voltage rate-of-change, the system achieves higher reliability without requiring complex additional hardware.
2Measurement precision
If simple voltage threshold monitoring is used, then the device complexity remains low, but the detection precision and ability to distinguish broken conductors from other faults is insufficient
Solution Approach 1:
The patent changes the detection parameter from simple voltage magnitude to the derivative of zero-sequence voltage with respect to time. This parameter transformation enables precise detection of broken conductors by capturing the rapid rate-of-change characteristic that distinguishes broken conductor faults from other power system disturbances. The derivative parameter provides superior measurement precision.
3Speed
If rapid detection of broken conductors is implemented, then the safety and reliability improve, but the response time and speed requirements increase system complexity
Solution Approach 1:
The patent performs preliminary computational preparation by continuously calculating and storing the derivative of zero-sequence voltage in real-time. This preliminary action ensures that when a broken conductor occurs, the detection algorithm can immediately compare pre-computed derivative values against threshold criteria, achieving rapid detection without requiring complex real-time computation during the fault event.
Data Source
AI summary
A location of a broken electrical conductor of an electric power delivery system may be detected by monitoring a rate of change of phase voltage and/or a rate of change of zero-sequence voltage at various points on the conductor. Intelligent electronic devices (IEDs) such as phasor measurement units may be used to obtain measurements and calculate synchrophasors. The synchrophasors may be used by a central controller to determine which two continuous IEDs measure rates of change of voltages of opposite polarities, where the broken conductor is between the two continuous IEDs. The synchrophasors may be used by a central controller to determine which two continuous IEDs where one exhibits a zero-sequence voltage magnitude that exceeds a predetermined threshold for a predetermined time, wherein the zero-sequence voltage magnitude of the other of the continuous IEDs does not exceed the predetermined threshold.