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Low voltage ride-through strategies for a 3-phase grid-connected PV system / HAO WEN

Swansea University Author: HAO WEN

DOI (Published version): 10.23889/SUthesis.58526

Abstract

Grid codes is a technical specification which defines the parameters a power system that are connected to the national power systems has to ensure safe, secure and eco-nomic proper functioning of the electric system. One of these requirements is to stay connected to the grid during faults. In such s...

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Published: Swansea 2021
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Fazeli, Meghdad
URI: https://cronfa.swan.ac.uk/Record/cronfa58526
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last_indexed 2021-11-03T04:27:20Z
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fullrecord <?xml version="1.0"?><rfc1807><datestamp>2021-11-02T11:14:45.1030665</datestamp><bib-version>v2</bib-version><id>58526</id><entry>2021-11-02</entry><title>Low voltage ride-through strategies for a 3-phase grid-connected PV system</title><swanseaauthors><author><sid>ad3b8037520649ebb1f219d2d0445e1e</sid><firstname>HAO</firstname><surname>WEN</surname><name>HAO WEN</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2021-11-02</date><abstract>Grid codes is a technical specification which defines the parameters a power system that are connected to the national power systems has to ensure safe, secure and eco-nomic proper functioning of the electric system. One of these requirements is to stay connected to the grid during faults. In such scenarios, the generating unit should remain connected to the grid for a certain period and provide reactive power to support the grid. This is called low voltage ride-through capability. At the early stage, low voltage ride-through requirements were imposed for large scale generators connected to the trans-mission network. However, with the increased penetration of distributed generation, such as PV panels implemented in the distribution network, the low voltage ride-through requirements are also required for distributed generation. With the maturity of PV technology, the cost of PV generation has decreased. Therefore, the total installed capacity of grid-connected PV generation has increased; this has cre-ated new challenges to the low voltage ride-through. Power quality and transient per-formance are the most critical aspects of the grid-connected PV systems under grid faults. PV generation is permitted to switch off from the grid during a fault; however, with the high penetration of the installed PV system, it will degrade the power quality if the same method applied. It is necessary to make sure that the inverter currents remain sinusoidal and within the acceptable limits at the instant of the fault, during and after the fault clearance for different types of faults. Accordingly, this thesis proposes two low voltage ride-through strategies for a 3-phase grid-connected PV system in different reference frames. The presented low voltage ride-through control algorithm in the synchronous reference frame, which fulfils a voltage compensation unit and the reactive power injection block is designed to protect the inverter from overcurrent failure under both symmetrical and asymmetrical faults, reduce the double grid frequency oscillations and provides reac-tive power support by applying a voltage compensation unit. The inverter can also inject sinusoidal current during asymmetrical faults. The method does not require a hard switch from the Maximum Power Point Tracking to a non-Maximum Power Point Tracking algorithm, which ensures a smooth transition. The proposed method in the stationary reference frame provides a fast post-fault recov-ery, which is essential to minimize the fault impacts on the loads and the converter. The method, which consists of a new reference currents calculation block and the voltage compensation unit, maintains the converter current within acceptable limits, produces sinusoidal current even during asymmetrical faults, improves the post-fault recovery performance, and provides independent control for active and reactive powers.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>PV system, Low voltage ride-through, current controller</keywords><publishedDay>2</publishedDay><publishedMonth>11</publishedMonth><publishedYear>2021</publishedYear><publishedDate>2021-11-02</publishedDate><doi>10.23889/SUthesis.58526</doi><url/><notes>ORCiD identifier: https://orcid.org/0000-0001-8573-8749</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Fazeli, Meghdad</supervisor><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><apcterm/><lastEdited>2021-11-02T11:14:45.1030665</lastEdited><Created>2021-11-02T10:58:39.2690877</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Uncategorised</level></path><authors><author><firstname>HAO</firstname><surname>WEN</surname><order>1</order></author></authors><documents><document><filename>58526__21402__621e3cb5a17147be8ee17128c8b2abcc.pdf</filename><originalFilename>Wen_Hao_PhD_Thesis_Final_Redacted_Signature.pdf</originalFilename><uploaded>2021-11-02T11:07:02.7971572</uploaded><type>Output</type><contentLength>9395330</contentLength><contentType>application/pdf</contentType><version>E-Thesis &#x2013; open access</version><cronfaStatus>true</cronfaStatus><documentNotes>Copyright, The author, Hao Wen, 2021.</documentNotes><copyrightCorrect>true</copyrightCorrect><language>eng</language></document></documents><OutputDurs/></rfc1807>
spelling 2021-11-02T11:14:45.1030665 v2 58526 2021-11-02 Low voltage ride-through strategies for a 3-phase grid-connected PV system ad3b8037520649ebb1f219d2d0445e1e HAO WEN HAO WEN true false 2021-11-02 Grid codes is a technical specification which defines the parameters a power system that are connected to the national power systems has to ensure safe, secure and eco-nomic proper functioning of the electric system. One of these requirements is to stay connected to the grid during faults. In such scenarios, the generating unit should remain connected to the grid for a certain period and provide reactive power to support the grid. This is called low voltage ride-through capability. At the early stage, low voltage ride-through requirements were imposed for large scale generators connected to the trans-mission network. However, with the increased penetration of distributed generation, such as PV panels implemented in the distribution network, the low voltage ride-through requirements are also required for distributed generation. With the maturity of PV technology, the cost of PV generation has decreased. Therefore, the total installed capacity of grid-connected PV generation has increased; this has cre-ated new challenges to the low voltage ride-through. Power quality and transient per-formance are the most critical aspects of the grid-connected PV systems under grid faults. PV generation is permitted to switch off from the grid during a fault; however, with the high penetration of the installed PV system, it will degrade the power quality if the same method applied. It is necessary to make sure that the inverter currents remain sinusoidal and within the acceptable limits at the instant of the fault, during and after the fault clearance for different types of faults. Accordingly, this thesis proposes two low voltage ride-through strategies for a 3-phase grid-connected PV system in different reference frames. The presented low voltage ride-through control algorithm in the synchronous reference frame, which fulfils a voltage compensation unit and the reactive power injection block is designed to protect the inverter from overcurrent failure under both symmetrical and asymmetrical faults, reduce the double grid frequency oscillations and provides reac-tive power support by applying a voltage compensation unit. The inverter can also inject sinusoidal current during asymmetrical faults. The method does not require a hard switch from the Maximum Power Point Tracking to a non-Maximum Power Point Tracking algorithm, which ensures a smooth transition. The proposed method in the stationary reference frame provides a fast post-fault recov-ery, which is essential to minimize the fault impacts on the loads and the converter. The method, which consists of a new reference currents calculation block and the voltage compensation unit, maintains the converter current within acceptable limits, produces sinusoidal current even during asymmetrical faults, improves the post-fault recovery performance, and provides independent control for active and reactive powers. E-Thesis Swansea PV system, Low voltage ride-through, current controller 2 11 2021 2021-11-02 10.23889/SUthesis.58526 ORCiD identifier: https://orcid.org/0000-0001-8573-8749 COLLEGE NANME COLLEGE CODE Swansea University Fazeli, Meghdad Doctoral Ph.D 2021-11-02T11:14:45.1030665 2021-11-02T10:58:39.2690877 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised HAO WEN 1 58526__21402__621e3cb5a17147be8ee17128c8b2abcc.pdf Wen_Hao_PhD_Thesis_Final_Redacted_Signature.pdf 2021-11-02T11:07:02.7971572 Output 9395330 application/pdf E-Thesis – open access true Copyright, The author, Hao Wen, 2021. true eng
title Low voltage ride-through strategies for a 3-phase grid-connected PV system
spellingShingle Low voltage ride-through strategies for a 3-phase grid-connected PV system
HAO WEN
title_short Low voltage ride-through strategies for a 3-phase grid-connected PV system
title_full Low voltage ride-through strategies for a 3-phase grid-connected PV system
title_fullStr Low voltage ride-through strategies for a 3-phase grid-connected PV system
title_full_unstemmed Low voltage ride-through strategies for a 3-phase grid-connected PV system
title_sort Low voltage ride-through strategies for a 3-phase grid-connected PV system
author_id_str_mv ad3b8037520649ebb1f219d2d0445e1e
author_id_fullname_str_mv ad3b8037520649ebb1f219d2d0445e1e_***_HAO WEN
author HAO WEN
author2 HAO WEN
format E-Thesis
publishDate 2021
institution Swansea University
doi_str_mv 10.23889/SUthesis.58526
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
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description Grid codes is a technical specification which defines the parameters a power system that are connected to the national power systems has to ensure safe, secure and eco-nomic proper functioning of the electric system. One of these requirements is to stay connected to the grid during faults. In such scenarios, the generating unit should remain connected to the grid for a certain period and provide reactive power to support the grid. This is called low voltage ride-through capability. At the early stage, low voltage ride-through requirements were imposed for large scale generators connected to the trans-mission network. However, with the increased penetration of distributed generation, such as PV panels implemented in the distribution network, the low voltage ride-through requirements are also required for distributed generation. With the maturity of PV technology, the cost of PV generation has decreased. Therefore, the total installed capacity of grid-connected PV generation has increased; this has cre-ated new challenges to the low voltage ride-through. Power quality and transient per-formance are the most critical aspects of the grid-connected PV systems under grid faults. PV generation is permitted to switch off from the grid during a fault; however, with the high penetration of the installed PV system, it will degrade the power quality if the same method applied. It is necessary to make sure that the inverter currents remain sinusoidal and within the acceptable limits at the instant of the fault, during and after the fault clearance for different types of faults. Accordingly, this thesis proposes two low voltage ride-through strategies for a 3-phase grid-connected PV system in different reference frames. The presented low voltage ride-through control algorithm in the synchronous reference frame, which fulfils a voltage compensation unit and the reactive power injection block is designed to protect the inverter from overcurrent failure under both symmetrical and asymmetrical faults, reduce the double grid frequency oscillations and provides reac-tive power support by applying a voltage compensation unit. The inverter can also inject sinusoidal current during asymmetrical faults. The method does not require a hard switch from the Maximum Power Point Tracking to a non-Maximum Power Point Tracking algorithm, which ensures a smooth transition. The proposed method in the stationary reference frame provides a fast post-fault recov-ery, which is essential to minimize the fault impacts on the loads and the converter. The method, which consists of a new reference currents calculation block and the voltage compensation unit, maintains the converter current within acceptable limits, produces sinusoidal current even during asymmetrical faults, improves the post-fault recovery performance, and provides independent control for active and reactive powers.
published_date 2021-11-02T04:15:07Z
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score 11.036531

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