Fault Location in Two-Terminal Power Lines Using Single-Ended Voltage
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Solution Overview
Problem
Existing methods for locating faults in two-terminal power transmission or distribution lines require complete measurements from both ends, which can be impractical due to the need for synchronized data and may not function if communication from one end is disrupted, and often require knowledge of source impedances.
Innovation Solution
A method and device using synchronized three-phase current measurements from both terminals and three-phase voltage measurements from one terminal, allowing for fault location without complete data from both ends and without requiring knowledge of source impedances, utilizing an impedance-based algorithm that determines fault distance and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete measurements from both terminals are used for fault location, then measurement precision is improved, but device complexity and communication requirements increase
Solution Approach 1:
The invention extracts and utilizes only the necessary measurement components (currents from both terminals and voltages from one terminal) required for accurate fault location, eliminating the need for complete measurements from both terminals. This reduces communication requirements and system complexity while maintaining fault location accuracy.
Solution Approach 2:
The invention applies partial action by using measurements from only one terminal for voltage data, rather than requiring complete synchronized measurements from both terminals. This partial measurement approach achieves sufficient fault location precision without the overhead of complete two-terminal measurements.
2Measurement precision
If synchronized measurements from both terminals are required, then fault location accuracy is improved, but reliability decreases when communication is disrupted
Solution Approach 1:
The invention removes the dependency on communication between terminals by extracting and using only locally available measurements (currents from both terminals and voltages from one terminal). This eliminates the single point of failure associated with communication disruptions while maintaining fault location accuracy.
Solution Approach 2:
The fault location system serves itself by using only measurements that can be obtained locally at one terminal, without requiring data exchange or synchronization with the other terminal. This self-sufficient approach ensures reliability even when communication is disrupted.
3Measurement precision
If source impedance knowledge is required for fault location, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The invention makes the system self-sufficient by calculating fault location using only measured quantities (currents and voltages) without requiring external knowledge of source impedances. The method derives all necessary information from the measurements themselves, eliminating the need for additional system parameters.
Solution Approach 2:
The invention changes the approach from using fixed system parameters (source impedances) to using dynamic measured parameters (currents and voltages). This transformation allows the system to adapt to changing conditions while maintaining precision without requiring prior knowledge of source characteristics.
Data Source
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AI summary
A method for locating a fault in a two-terminal power transmission or distribution line comprises the steps of receiving measurements of the three phase currents from both terminals, receiving measurements of the three phase voltages from one line terminal, receiving parameters of the line and receiving the fault type. Based on this information the distance to fault from the one terminal where the phase voltages were measured is determined and output. Since only the phase voltages of one line terminal are needed, the functionality of a device, in particular a current 15 differential relay, can be expanded to determine the distance to fault in an off-line mode.