Parameter-Free Fault Location in Multi-Terminal Power Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Accurate fault location identification in multi-terminal power transmission lines is challenging due to varying line parameters, mutual coupling, and the need for precise input data, especially in three-terminal/tapped lines, where conventional methods are inaccurate and require knowledge of source impedance and fault loop information.
Innovation Solution
The method employs synchronized measurements from Intelligent Electronic Devices (IEDs) to compute line parameters using Newton Raphson approximation, determining resistance, inductance, and capacitance per unit length, and identifies fault locations without prior knowledge of line parameters by analyzing voltage and current phasors through a distributed two-port network model.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fault location identification methods are used in multi-terminal power transmission lines, then the fault location can be identified, but the accuracy is poor due to varying line parameters, mutual coupling, and dependency on precise input data
Solution Approach 1:
The patent transforms the fault location identification problem from a complex multi-parameter dependency to a simplified single-parameter measurement. By measuring only the active power at the healthy terminal and using the known healthy line parameters, the method eliminates dependencies on source impedance angles, fault loop information, and other complex parameters. The fault location is directly calculated from the measured active power and pre-stored healthy line parameters, achieving high accuracy without complex device requirements.
Solution Approach 2:
The patent extracts and utilizes only the essential healthy line parameters (resistance, inductance, capacitance per unit length) while eliminating the need for other complex parameters such as source impedance angles, fault loop information, and mutual coupling data. By focusing solely on the healthy terminal's active power measurement and the known healthy line characteristics, the method simplifies the fault location identification process while maintaining high accuracy in multi-terminal configurations.
2Measurement precision
If impedance based fault location identification methods are used, then fault location can be estimated, but the accuracy depends on multiple factors including mutual coupling, non-homogeneity of line, source impedance angles, source to line impedance ratio, fault resistance and fault loop information
Solution Approach 1:
The patent extracts and utilizes only the essential healthy line parameters (resistance, inductance, capacitance per unit length) while eliminating the need for other complex parameters such as source impedance angles, fault loop information, and mutual coupling data. By focusing solely on the healthy terminal's active power measurement and the known healthy line characteristics, the method simplifies the fault location identification process while maintaining high accuracy in multi-terminal configurations.
Solution Approach 2:
The healthy terminal automatically provides the necessary information for fault location identification through its active power measurement. The method uses the healthy line parameters (which are inherent to the line itself) and the measured active power at the healthy terminal to directly calculate the fault location, eliminating the need for external information from faulted terminals or additional measurements. The healthy portion of the system serves itself to identify faults in the damaged portion.
3Productivity
If three-terminal/tapped lines are used to supply power reliably, then power transfer capability is improved, but accurate fault location identification becomes challenging due to different section lengths, per unit impedance, infeed, and charging current
Solution Approach 1:
The patent segments the multi-terminal power transmission line into healthy and faulted sections, focusing measurements and calculations solely on the healthy terminal. By treating the healthy portion as a separate, well-characterized segment with known parameters, the method avoids the complexities introduced by the faulted sections and multiple injection points. This segmentation approach enables accurate fault location identification in multi-terminal configurations by isolating the measurement to a single healthy terminal.
4Reliability
If fast restoration of outages is implemented, then reliability is improved, but accurate and quick fault location identification is required which complicates the system
Solution Approach 1:
The healthy terminal automatically provides the necessary information for fault location identification through its active power measurement. The method uses the healthy line parameters (which are inherent to the line itself) and the measured active power at the healthy terminal to directly calculate the fault location, eliminating the need for external information from faulted terminals or additional measurements. The healthy portion of the system serves itself to identify faults in the damaged portion.
Solution Approach 2:
The healthy line parameters (resistance, inductance, capacitance per unit length) are pre-calculated and stored before any fault occurs. This preliminary preparation eliminates the need for real-time calculation of complex parameters during fault conditions. When a fault occurs, the system immediately uses the pre-stored healthy parameters combined with the current active power measurement to quickly determine fault location, enabling fast restoration without complex real-time computations.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Identifying a fault location in a power transmission line (402) includes obtaining synchronized disturbance records from each of the terminals after a fault has occurred in the power transmission line (402). Pre-fault voltage and current phasors and during-fault current and voltage phasors are computed based on the disturbance records. Values for propagation constant, surge impedance, and a fault location parameter are computed based on simultaneously solving a plurality of pre-fault objective functions and during-fault objective functions for an assumed faulted section. The values determined are compared with predefined criteria to determine a faulted section, the fault location, and the line parameters for each of the sections, thus implementing parameter free identification of fault location.