Transmission Fault Location Using Instantaneous Reactance Signals
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Solution Overview
Problem
Existing fault location determination methods during power swings in power transmission systems suffer from significant errors due to modulation of voltage and current signals, leading to inaccurate phasor estimations and prolonged identification of fault locations, which are time-consuming and resource-intensive.
Innovation Solution
A single-ended fault location method using instantaneous values of three-phase voltages and currents measured at the local terminal, employing moving window average filters to calculate equivalent reactance, and refining fault locations through convergence analysis, eliminating the need for source impedance information and reducing operation time by 50% to about 5 ms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fault location determination methods are used during power swings, then fault location can be identified, but significant errors occur due to modulation of voltage and current signals leading to inaccurate phasor estimations
Solution Approach 1:
The patent extracts and eliminates the problematic phasor estimation step from the fault location determination process. By directly using instantaneous voltage and current values without converting to phasors, the method removes the source of error that occurs during power swings, thereby resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent changes the parameter domain from phasor domain to time domain by using instantaneous values of voltage and current. This parameter transformation allows direct calculation of fault location without the modulation issues that affect phasor estimations during power swings, improving both accuracy and reliability simultaneously.
2Productivity
If existing fault location methods are used, then fault identification can be performed, but the process is time-consuming and resource-intensive
Solution Approach 1:
The patent segments the fault location determination into a simplified single-ended calculation using only local terminal measurements. This segmentation eliminates the need for complex synchronized measurements from multiple terminals and iterative phasor estimation processes, significantly reducing computation time and resources while improving productivity.
Solution Approach 2:
The patent performs preliminary filtering of voltage and current signals using moving average filters before fault location calculation. This preliminary action prepares clean input data that enables faster and more accurate fault location determination, reducing both operation time and computational resource requirements.
3Ease of manufacture
If single-ended measurement method is used, then communication losses are avoided and installation costs are reduced, but accurate fault location determination during power swings becomes challenging
Solution Approach 1:
The patent implements a self-service measurement system that uses only local terminal measurements to determine fault location. By formulating calculation methods that inherently account for power swing conditions using solely local voltage and current data, the system eliminates the need for communication infrastructure while maintaining high measurement precision during challenging power swing scenarios.
Data Source
AI summary
Fault location determination in a power transmission system is described. Samples of voltage and current measured are obtained for each phase at a terminal. A first equivalent reactance value based on the samples of voltage and current is calculated. Further, based on the calculated equivalent reactance value a first fault location is determined.