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The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613878823682048 |
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| access_status_str | Open Access |
| author | Du Plessis, Francois |
| author2 | Beukes, Johan |
| author_browse | Beukes, Johan Du Plessis, Francois |
| author_facet | Beukes, Johan Du Plessis, Francois |
| author_sort | Du Plessis, Francois |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127171 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:43:09.148Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127171 The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants Du Plessis, Francois Beukes, Johan Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. small-signal impedance modelling; grid-tied inverters; harmonic studies; renewable power plants Photovoltaic power systems Electric inverters Impedance (Electricity) Renewable natural resources Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: Increased penetration of renewable power plants on the South African power network presents technical and regulatory challenges. Power quality problems and compliance assessment methods related to harmonic emissions of renewable power plants are studied. The elements which influence the harmonic emissions of renewable power plants are identified as the inverter harmonic source, the plant impedance, the grid impedance and background distortion levels. An accurate description of the plant impedance is discussed and includes the inverter filter inductor and control system. These elements have a significant impact in the low frequency region. The negative resistive characteristic of the controller and its interaction with system resonances is identified as a limitation on the controller bandwidth to ensure resonant stability. The inverter impedance description is used to investigate the impact of parameter variations on harmonic emissions of a simulated 2.3 MVA inverter system, including variations in controller topology and bandwidth, grid impedance and harmonic compensation. The harmonic contributions of a 100 kVA inverter and 2.3 MVA inverter on a shared feeder are identified using descriptions of the impedances. A harmonic study of an 80 kVA experimental inverter system is conducted. The effects of variations in controller bandwidth, filter capacitance and grid impedance on harmonic distortion are investigated. The inverter impedance description is used to accurately characterise the plant impedance of a 100 MW wind farm, which enables the attribution of harmonic contributions from measured data. Phasor analysis in the phase and sequence domains are compared and challenges of harmonic assessment methods are discussed. AFRIKAANS OPSOMMING: Verhoogde penetrasie van hernubare kragbronne op die Suid-Afrikaanse kragnetwerk bied baie tegniese en regulatoriese uitdagings. Assessering van die nakoming van harmoniese limiete en toevoerkwalitieits probleme geassosieer met hernubare kragprodusente word bestudeer. Die elemente wat die harmoniese bydraes van hernubare kragprodusente beïnvloed word geïdentifiseer as die harmoniese bron van die wisselrigter, die installasie impedansie, die netwerk impedansie en die agtergrond harmoniese vervormingsvlakke. ‘n Meer akkurate beskrywing van die installasie impedansie word bespreek en sluit die filter induktor en beheerstelsel van die wisselrigter in. Die insluiting van die elemente het ‘n wesenlike impak in die lae-frekwensie gebied. Die negatiewe weerstands gedrag van die beheerstelsel en die interaksie daarvan met resonansies in die sisteem word geïdentifiseer as ‘n beperking op die bandwydte van die beheerstelsel om resonante stabiliteit te verseker. Die beskrywing van die impedansie van die wisselrigter word gebruik om die impak van parameter veranderinge, insluitend variasies van beheerder topologie en bandwydte, netwerk impedansie en harmoniese kompensasie, op die harmoniese bydraes van ‘n 2.3 MVA wisselrigterstelsel te ondersoek. Die harmoniese bydraes van ‘n 100 kVA wisselrigter en 2.3 MVA wisselrigter op ‘n gemeenskaplike voerder word onderskei deur gebruik te maak van die impedansie beskrywings. ‘n 80 kVA eksperimentele wisselrigterstelsel word gebruik om die invloed van beheerbandwydte, netwerk impedansie en filter kapasitansie op harmoniese vervorming te ondersoek. Die beskrywing van die wisselrigter impedansie word gebruik om die harmoniese bydraes van ‘n 100 MW windplaas te bepaal uit gemete data, deur die installasie impedansie akkuraat te beskryf. Fasoranalise in fase en volgorde stelsels word vergelyk en uitdagings van die harmoniese toegeeflikheids assesserings metodes word bespreek. Masters 2023-03-02T08:32:26Z 2023-05-18T07:07:59Z 2023-03-02T08:32:26Z 2023-05-18T07:07:59Z 2023-03 Thesis http://hdl.handle.net/10019.1/127171 en_ZA en_ZA Stellenbosch University xix, 178 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | small-signal impedance modelling; grid-tied inverters; harmonic studies; renewable power plants Photovoltaic power systems Electric inverters Impedance (Electricity) Renewable natural resources Du Plessis, Francois The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants |
| title | The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants |
| title_full | The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants |
| title_fullStr | The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants |
| title_full_unstemmed | The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants |
| title_short | The use of small-signal impedance modelling of grid-tied inverters in harmonic studies of renewable power plants |
| title_sort | use of small signal impedance modelling of grid tied inverters in harmonic studies of renewable power plants |
| topic | small-signal impedance modelling; grid-tied inverters; harmonic studies; renewable power plants Photovoltaic power systems Electric inverters Impedance (Electricity) Renewable natural resources |
| url | http://hdl.handle.net/10019.1/127171 |
| work_keys_str_mv | AT duplessisfrancois theuseofsmallsignalimpedancemodellingofgridtiedinvertersinharmonicstudiesofrenewablepowerplants AT duplessisfrancois useofsmallsignalimpedancemodellingofgridtiedinvertersinharmonicstudiesofrenewablepowerplants |