Change search
ReferencesLink to record
Permanent link

Direct link
Synchronous Voltage Reversal Control of Thyristor Controlled Series Capacitor
KTH, Superseded Departments, Electrical Systems.
2002 (English)Doctoral thesis, monograph (Other scientific)
Abstract [en]

Series compensation of transmission lines is an effectiveand cheap method of improving the power transmission systemperformance. Series capacitors virtually reduces the length ofthe line making it easier to keep all parts of the power systemrunning in synchronism and to maintain a constant voltage levelthroughout the system. In Sweden this technology has been inuse since almost 50 years.

The possibility to improve the performance of the ACtransmission system utilizing power electronic equipment hasbeen discussed a lot since about ten years. Some newsemiconductor based concepts have been developed beside thesince long established HVDC and SVC technologies. The ThyristorControlled Series Capacitor (TCSC) is one such concept. Byvarying the inserted reactance an immediate and well-definedimpact on the active power flow in the transmission line isobtained. Several potential applications, specifically poweroscillation damping, benefit from this capability. The conceptimplied the requirement to design a semiconductor valve, whichcan be inserted directly in the high-voltage power circuit.This certainly presented a technical challenge but thestraightforward approach appeared to be a cost-effectivealternative with small losses.

It was also realized that the TCSC exhibits quite differentbehaviour with respect to subsynchronous frequency componentsin the line current as compared to the fixed series capacitorbank. This was a very interesting aspect as the risk ofsubsynchronous resonance (SSR), which just involves such linecurrent components, has hampered the use of series compensationin power systems using thermal generating plants.

The thesis deals with the modelling and control aspects ofTCSC. A simplifying concept, the equivalent, instantaneousvoltage reversal, is introduced to represent the action of thethyristor controlled inductive branch, which is connected inparallel with the series capacitor bank in the TCSC. The idealvoltage reversal is used in the thesis in order to describe andexplain the TCSC dynamics, to investigate its apparentimpedance at various frequencies, as a platform forsynthesizing the boost control system and as the base elementin deriving a linear, small-signal dynamical model of thethree-phase TCSC. Quantitative Feedback Theory (QFT) then hasbeen applied to the TCSC model in order to tune its boostregulator taking into account the typical variation ofparameters that exists in a power system. The impact of theboost control system with respect to damping of SSR is finallybeing briefly looked at.

Keywords:Thyristor Controlled Series Capacitor, TCSC,FACTS, reactive power compensation, boost control, phasorestimation, Quantitative Feedback Theory, subsynchronousresonance, SSR.

Place, publisher, year, edition, pages
Stockholm: Elektrotekniska system , 2002. , 246 p.
Trita-ETS, ISSN 1650-674X ; 2002:07
Keyword [en]
ThyristorControlled Series Capacitor, TCSC, FACTS, reactive power compensation, boost control, phasor estimation, Quantitative Feedback Theory, subsynchronous resonance, SSR
URN: urn:nbn:se:kth:diva-3396ISBN: OAI: diva2:9191
Public defence
NR 20140805Available from: 2002-09-09 Created: 2002-09-09Bibliographically approved

Open Access in DiVA

fulltext(5792 kB)8989 downloads
File information
File name FULLTEXT01.pdfFile size 5792 kBChecksum MD5
Type fulltextMimetype application/pdf

By organisation
Electrical Systems

Search outside of DiVA

GoogleGoogle Scholar
Total: 8989 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 1433 hits
ReferencesLink to record
Permanent link

Direct link