uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Failure-Modes Demonstration and Redundant Postfault Operation of Rotating Thyristor Rectifiers on Brushless Dual-Star Exciters
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.ORCID iD: 0000-0001-8237-3107
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
(English)In: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948Article in journal (Refereed) Submitted
Abstract [en]

The excitation system plays a critical role for the operation of synchronous generators. A potential equipment failure impacts the voltage quality for smaller grids. Further, it can cause cost penalties and reduced production for the power plant owner. Recently, a new high-speed response rotating brushless exciter employs remote control of rotating thyristors on the generator shaft. It has lead to need possibilities for improved performance of brushless exciters. This contribution investigates a dual-star outer pole permanent magnet exciter feeding two separate thyristor bridges, which are connected in parallel during normal operation. The possibility of redundant post-fault operation due to open-thyristor or open-phase faults are demonstrated from experimental testing. The system is compared with the faulty performance of the conventional three-phase system. Furthermore, a fault-predicting double-dq exciter model is implemented and validated. In addition, the dangerous effects of a shorted-thyristor fault is investigated. Moreover, a ”skip firing” protection algorithm is briefly demonstrated for fast isolation of such faults, yielding nondestructive postfault recovery. The evidence shows that the dual-star exciter is a competitive choice for the future developments of fault-tolerant brushless exciters.

Keyword [en]
Brushless exciters, double-star windings, dual-port electrical machines, 12-pulse thyristor bridges, open-phase faults, open-thyristor faults, shorted thyristors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
URN: urn:nbn:se:uu:diva-333567OAI: oai:DiVA.org:uu-333567DiVA: diva2:1157152
Available from: 2017-11-15 Created: 2017-11-15 Last updated: 2017-11-20
In thesis
1. Improving the functionality of synchronous machines using power electronics
Open this publication in new window or tab >>Improving the functionality of synchronous machines using power electronics
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

With the advent of modern power electronics there is reason to explore what can be achieved when it is applied to a mature technology like synchronous machines. In this text several concepts will be presented on how it is possible to control forces and how to get better performance out of synchronous machines by using power electronics. Methodologies to create radial forces by controlling the field current in a standard series connected rotor winding as well as when the winding is split in to several segments is presented. By segmenting the rotor a resulting force vector can be created to cancel forces due to unbalanced magnetic pull.

It is also shown that inverting the field current with respect to the stator field enables line start of synchronous machines without using damper bars, frequency converters, or starting motors.

Some first results from the installation and testing of an electromagnetic thrust bearing installed in unit U9 in the hydropower station in Porjus are presented. The benefits of the system is increased reliability and higher efficiency of the thrust bearing system.

An evaluation of a 2-stage brushless excitation system was done, different rotating power electronics topologies were tested in the stationary frame connected to a six-phase permanent magnet brushless exciter. The rotating control and measurement system for the power electronics is presented. Potential benefits of the system is that there is no need for brushes to transfer the field current to the rotor winding, fast response time due to actively controlled electronics, independence of the station bus voltage, and reduced maintenance.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017
Series
UURIE / Uppsala University, Department of Engineering Sciences, ISSN 0349-8352 ; 352-17L
Keyword
Power electronics, Synchronous machines, Excitation systems, Magnetic thrust bearing, Starting synchronous machines, Split rotor, Rotating electronics, Magnetic fields, Measurement systems, Unbalanced magnetic pull, Harmonics
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-333940 (URN)
Presentation
2017-12-18, Häggsalen (Å10132), Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2018-01-08 Created: 2017-11-20 Last updated: 2018-01-08Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Nöland, JonasEvestedt, FredrikLundin, Urban
By organisation
Electricity
In the same journal
IEEE transactions on industrial electronics (1982. Print)
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 26 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf