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dc.contributor.authorLazarevich, Alison Kayen_US
dc.date.accessioned2014-03-14T20:36:25Z
dc.date.available2014-03-14T20:36:25Z
dc.date.issued2003-05-12en_US
dc.identifier.otheretd-05122003-161802en_US
dc.identifier.urihttp://hdl.handle.net/10919/32624
dc.description.abstractA partial discharge (PD) is the dissipation of energy caused by the buildup of localized electric field intensity. In high voltage devices such as transformers, this buildup of charge and its release can be symptomatic of problems associated with aging, such as floating components and insulation breakdown. This is why PD detection is used in power systems to monitor the state of health of high voltage transformers. If such problems are not detected and repaired, the strength and frequency of PDs increases and eventually leads to the catastrophic failure of the transformer, which can cause external equipment damage, fires and loss of revenue due to an unscheduled outage. Reliable online PD detection is a critical need for power companies to improve personnel safety and decrease the potential for loss of service. The PD phenomenon is manifested in a variety of physically observable signals including electric and acoustic pulses and is currently detected using a host of exterior measurement techniques. These techniques include electrical lead tapping and piezoelectric transducer (PZT) based acoustic detection. Many modern systems use a combination of these techniques because electrical detection is an older and proven technology and acoustic detection allows for the source to be located when several sensors are mounted to the exterior of the tank. However, if an acoustic sensor could be placed inside the tank, not only would acoustic detection be easier due to the increased signal amplitude and elimination of multipath interference, but positioning could also be performed with more accuracy in a shorter time. This thesis presents a fiber optic acoustic sensing system design that can be used to detect and locate PD sources within a high voltage transformer. The system is based on an optical acoustic (OA) sensor that is capable of surviving the harsh environment of the transformer interior while not compromising the transformerâ s functionality, which allows for online detection and positioning. This thesis presents the theoretical functionality and experimental validation of a band-limited OA sensor with a usable range of 100-300 kHz, which is consistent with the frequency content of an acoustic pulse caused by a PD event. It also presents a positioning system using the time difference of arrival (TDOA) of the acoustic pulse with respect to four sensors that is capable of reporting the three-dimensional position of a PD to within ±5cm on any axis.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartthesis_fin.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectTime Difference of Arrival (TDOA)en_US
dc.subjectHigh Voltage Transformer (HVT)en_US
dc.subjectAcoustic Emissionen_US
dc.subjectPartial Discharge (PD)en_US
dc.subjectHyperbolic Positioningen_US
dc.subjectFiber Optic Acoustic Sensoren_US
dc.titlePartial Discharge Detection and Localization in High Voltage Transformers Using an Optical Acoustic Sensoren_US
dc.typeThesisen_US
dc.contributor.departmentElectrical and Computer Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineElectrical and Computer Engineeringen_US
dc.contributor.committeechairWang, Anboen_US
dc.contributor.committeememberLiu, Yiluen_US
dc.contributor.committeememberScales, Wayne A.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05122003-161802/en_US
dc.date.sdate2003-05-12en_US
dc.date.rdate2003-05-27
dc.date.adate2003-05-27en_US


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