Inverter control for voltage unbalance mitigation on low voltage electricity networks

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dc.contributor.advisorBeukes, Johanen_ZA
dc.contributor.authorDe Wet, Werneren_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.en_ZA
dc.date.accessioned2024-03-04T08:48:38Zen_ZA
dc.date.accessioned2024-04-26T22:20:57Zen_ZA
dc.date.available2024-03-04T08:48:38Zen_ZA
dc.date.available2024-04-26T22:20:57Zen_ZA
dc.date.issued2024-03en_ZA
dc.descriptionThesis (MEng)--Stellenbosch University, 2024.en_ZA
dc.description.abstractENGLISH ABSTRACT: The use of single-phase power lines to electrify low consumption areas in South Africa leads to undesired levels of voltage unbalance at certain point on the distribution network. The increased use of inverter-based generation in the distribution network provides the opportunity for the utitlisation of these inverters to be increased by providing an ancillary service such as voltage regulation and voltage unbalance mitigation. This thesis provides a detailed design of a positive and negative sequence dq domain control system that can be implemented in grid-connected inverters to perform voltage regulation and voltage unbalance mitigation. This control system allows the inverter to perform voltage regulation by means of reactive power compensation and mitigate voltage unbalance by transferring active and reactive power between the three phases. The inverter system is experimentally tested by adapting an existing three-phase 80 kVA inverter and connecting it to the electricity grid. Resistive loads are connected to the inverter-grid system to generate undesired levels of voltage unbalance. The control system implemented in the inverter consists of an inner dual current controller which is supplied current references from an outer control loop than consists of the DC voltage controller, positive sequence voltage controller and a negative sequence voltage controller.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die gebruik van enkel fase krag lyne om lae elektrisiteitsverbruik areas in Suid Afrika te elektrifiseer lei tot ongewenste vlakke van spannings onbalans op sekere nodes van die distribusie netwerk. Die toename in die gebruik van wisselrigter gebaseerde opwekking in die distribusie netwerk verskaf die geleentheid om die nuttigheid van hierdie omsetters te vergroot deur aanvullende dienste te verskaf soos spannings regulasie en spannings onbalans versagting. Die tesis verskaf ’n omvattende ontwerp van ’n positiewe en negatiewe volgorde dq gebied beheerstelsel wat in netwerk gekoppelde wisselrigters geimplimenteer kan word om spannings regulasie en spannings onbalans versagting te bied. Die beheerstelsel laat die omsetter toe om spannings regulasie te bied deur reaktiewe drywing kompensasie toe te pas en om spannings onbalans versagting toe te pas deur aktiewe en reaktiewe drywing tussen die drie fases oor te dra. Die wisselrigter sisteem is eksperimenteel getoets deur ’n bestaande drie-fase 80 kVA wisselrigter aan te pas en aan die elektrisiteit netwerk te koppel. Resistiewe laste word gekoppel aan die netwerk gekoppelde wisselrigter sisteem om ongewenste vlakke van spannings onbalans by die wisselrigter se netwerk konneksie punt te genereer. Die geimplimenteerde beheerstelsel bestaan uit ’n binne lus dubbel stroom beheerder wat stroom verwysings kry vanaf ’n buite lus wat bestaan uit ’n GS spannings beheerder, positiewe volgorde spannings beheerder en ’n negatiewe volgorde spannings beheerder.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxix, 148 pages : illustrations.en_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/130568en_ZA
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshElectric invertersen_ZA
dc.subject.lcshVoltage regulatorsen_ZA
dc.subject.lcshLow voltage systemsen_ZA
dc.subject.lcshElectric power distributionen_ZA
dc.subject.lcshUCTDen_ZA
dc.titleInverter control for voltage unbalance mitigation on low voltage electricity networksen_ZA
dc.typeThesisen_ZA
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