Power Transmission Fault Location During Power Swings
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Solution Overview
Problem
Existing methods for fault location determination during power swings in power transmission systems are inaccurate due to modulation of voltage and current signals, leading to significant errors in phasor estimations, which prolong the time required to identify the exact fault point.
Innovation Solution
A method utilizing instantaneous values of three-phase voltages and currents measured at the local terminal, calculating equivalent reactance based on sampled values, and applying moving window average filters to determine a refined fault location, which is single-ended and time-domain based, avoiding the need for communication and additional installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phasor estimation methods are used during power swings, then fault location can be determined, but significant errors occur due to signal modulation
Solution Approach 1:
The patent changes the fundamental parameter being measured from phasor estimates to instantaneous voltage and current values. By working directly in the time domain with instantaneous samples rather than transforming to phasors, the method avoids the modulation errors that plague phasor estimation during power swings, thereby maintaining both accuracy and reliability
Solution Approach 2:
The patent substitutes the traditional phasor-based measurement approach with a time-domain instantaneous value approach. This replacement eliminates the need for signal transformation and filtering operations that introduce errors during power swings, directly measuring fault location from raw instantaneous voltage and current samples
2Measurement precision
If communication between terminals is used for fault location determination, then more accurate results can be achieved, but data loss over communication and system complexity increase
Solution Approach 1:
The patent enables the local terminal to determine fault location independently using only locally measured instantaneous voltage and current values. This self-service approach eliminates the need for communication with remote terminals, avoiding data loss issues and reducing system complexity while maintaining accurate fault location determination
Solution Approach 2:
The patent extracts the fault location determination capability to operate independently at the local terminal by removing the dependency on communication with other terminals. By using only locally available instantaneous voltage and current measurements, the system eliminates the communication infrastructure requirement and its associated complexities
3Reliability
If conventional fault location methods are used during power swings, then fault detection is possible, but operation time increases significantly
Solution Approach 1:
The patent skips the time-consuming intermediate steps of phasor transformation, signal filtering, and complex calculations required by conventional methods. By directly calculating fault location from instantaneous voltage and current values using simple algebraic operations, the method rushes through the computation process, reducing operation time by 50% or more while maintaining reliability
Solution Approach 2:
The patent performs preliminary sampling of voltage and current at the moment of fault detection, capturing instantaneous values that can be immediately processed. This preliminary capture of data in the time domain allows for rapid fault location calculation without waiting for complete power cycles or complex signal processing to converge
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.