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Study On The Fault Location In Transmission Lines Based On Wavelet Transform

Posted on:2013-01-03Degree:MasterType:Thesis
Country:ChinaCandidate:Y L LiFull Text:PDF
GTID:2212330362963022Subject:Detection Technology and Automation
Abstract/Summary:PDF Full Text Request
Safe operation plays an important role for high voltage transmission system inpower systems. Once a fault occurs but could not be eliminated in time, it will lead toenormous economic loss. In recent years, various approaches have been studied in thefield of finding fault and fault-location. The FFT transforms is carried in the frequencydomain and cannot reflect the time domain characteristics of signals; while the wavelethas the characteristic of frequency-time localization, and it can extract fault informationeffectively.This paper presents a thorough study on lifting wavelet transform in fault signaldetection. Lifting wavelet is independent of the FFT, processes signal in the time domaincompletely, and has less computation compared with the first generation wavelet. So it isconducive to improve the real-time performance for signal detection. Fault transienttraveling waves of electric transmission line were collected and analyzed by the wavelettransform, and its modulus maximum could realize the traveling wave arrival time forprecise positioning. Wavelet analysis could not only detect the position of a fault pointaccurately, but display some other features of the fault transient component. So it is avery valuable processing tool in time-frequency domain.First, the related theories were expounded for fault location algorithms in this paper,including the basic concepts of wavelet transform, the multi-resolution analysisknowledge, the phase-mode transformation, the lifting wavelet transform, and thewavelet modulus maximum singularity detection theory.Secondly, the influence factors on the head of traveling waves were analyzed,including the process of transient traveling wave, the power system fault type, the faultinitial angle, the transition resistance, and the fault type as well as other factors. Thesingle terminal fault location method free of the wave-speed influence was specialized.Through summarizing the presented current fault location methods, the lifting wavelettransform was proposed to detect and analyze the transient signals, and the waveletmodulus maxima was adopted to detect the signal mutation.Finally, the experiments were designed for the method above. For the software part, MATLAB and PSB tools were used to build a transmission line fault simulation systemmodel. The algorithm simulation experiments for the traveling wave fault location of thegeneral single terminal and the wave-speed-free single terminal. As the hardware part, theoptical fiber current transformer system was designed and the characteristics of itscomponents were analyzed.
Keywords/Search Tags:fault location, travelling wave, lifting wavelet transform, modulus maximum, mingle terminal fault location
PDF Full Text Request
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