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Fault Line Selection And Section Location Approach Based On Compensation Characteristics Of Extinction Coil

Posted on:2015-05-29Degree:MasterType:Thesis
Country:ChinaCandidate:R Q SiFull Text:PDF
GTID:2272330422971645Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the further development of distribution network automation, people havehigher demands for power quality. Single-phase grounding fault has the highest rates ofin distribution network.However the approaches of single-phase grounded fault lineselection are not ideal. It suggested that it was necessary to study further.This paper firstly summarizes the basic working principles and the problemsexisting in the practical application of the existing fault line selection and sectionlocation approaches methods in domestic and foreign, And then analyzes thesteady-state and transient-state characteristics of NES singal-phase grounding fault.Asthe fault-line selection methods based on the transient direction are restricted by theinconsistent polarity of zero sequence current transformer, the transient energy(amplitude) line selection methods are unable to realize two loop lines system.In order to overcome the drawback, a new approach using compensationcharacteristics is proposed. The mathematical model for each line built as healthy onewithout earth grounding fault,can be solved with the transient component and steadycomponent of zero sequence voltage and current. With the compensation of extinctioncoil, two component parameters of fault line are opposite in sign which are similar forhealthy line.The transient component plays a key role to fault line selection,this paperpresents an improved algorithm of matrix method to solve the component annihilationfor high frequency extraction. In order to solve the extract problem of high frequencycomponent amplitude with small angle fault, decaying dc component is selected as theauxiliary criterion line selection methods to improve the scope and accuracy of lineselection method.NES was established based on the MATLAB simulation model.By setting thedifferent simulation conditions on line selection method for validation, and use thephysical simulation experiment for further validation.Simulation results verify thecorrectness of the algorithm without the impact of anti-polarity of zero sequenceCT,which has highly adaptive capacity for practical engineering.This paper presents animproved algorithm of matrix method to solve the component annihilation for highfrequency extractionAfter fault line selection, section location can be achieved with availableinformation, the FTU installed on the distribution network can be used as a segment information section features.As most FTU have no supporting installation of zerosequence voltage transformer, and the FTU communication may be a pair of milliseconderror,New characteristic is identified that Zero mode component current is under theconstraint of a line voltage transient when single-phase grounded fault. The differenceof zero mode current free oscillation component phase and line voltage free oscillationcomponent phase is not change over time. Matrix pencil is used to calculate two phasedifference which is defined as testing point indicates phase. New section locationmethod is put forward, indicates phases of the same side would be close and the ones ofdifferent sides would be opposite. The simulation results expatiate both the validity andthe effectiveness, a new idea may be provided for section location.
Keywords/Search Tags:NES, CT polarity, Matrix pencil, fault line selection, section location
PDF Full Text Request
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