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dc.contributor.author
Pfeiffer, Martin D.
dc.contributor.supervisor
Franck, Christian
dc.contributor.supervisor
Zhang, Bo
dc.date.accessioned
2017-10-23T11:19:34Z
dc.date.available
2017-10-23T10:42:21Z
dc.date.available
2017-10-23T11:19:34Z
dc.date.issued
2017-10-13
dc.identifier.uri
http://hdl.handle.net/20.500.11850/199298
dc.identifier.doi
10.3929/ethz-b-000199298
dc.description.abstract
For various applications, HVDC overhead lines (OHL) offer technical and economic advantages over conventional HVAC systems. Boosted by increased demand for transmission capacity, the number of HVDC systems has thus steadily risen over the past decades. Corona effects - processes related to partial electric discharges caused by high electric field stresses at conductor surfaces - are an important factor in the overall environmental, technical and economic performance of HVDC OHLs. They include corona losses, audible noise and the drift of ions towards ground or to other conductors. This latter aspect plays an important role in so-called hybrid AC/DC towers, in which HVAC and HVDC systems run in parallel on the same tower. This thesis investigates the fundamental effects that lead to the generation of corona discharges on DC conductors. The influence of conductor surface properties on the corona behavior during wet weather is given particular attention. Furthermore, the corona current coupling between different bundles in bipolar DC and hybrid AC/DC systems is studied in detail. A series of indoor laboratory experiments (monopolar DC, bipolar DC and hybrid AC/DC) form the basis of the presented investigations. Using simulated rainfall and novel imaging methods, the relationship between wetting behavior and corona properties is established. In bipolar DC and hybrid AC/DC measurements, the selective placement of corona sources is used to differentiate between coupling effects caused by Laplace (space-charge-free) fields and mechanisms driven by Poisson (space-charge-enhanced) fields. A key finding of this thesis is that the conductor surface type strongly influences wet weather HVDC corona losses and the drying rate after a rain shower. The latter is important since audible noise is increased during the drying phase. The presented results and methods can be used in the selection or further improvement of OHL conductors for HVDC applications. It was also determined that the local concentration of water drops on the lower side of the conductor influences the corona current coupling in bipolar HVDC systems. Neglecting this directional bias in ion flow simulations was shown to lead to significant prediction errors, in particular for narrow pole separations. Finally, for hybrid AC/DC systems it was shown that DC corona currents in AC and DC conductors are strongly affected by corona emissions on AC conductors. The fundamental reason for this was determined to be the existence of a net DC ion drift from AC conductors to DC conductors. Thus, there exists a bipolar space charge environment between a coronating AC and DC conductor. Neglecting AC corona in ion flow simulations was shown to lead to large under-predictions of the DC corona current in AC conductors. This thesis presents a simple empirical method to account for AC corona in hybrid AC/DC ion flow simulations.
en_US
dc.format
PDF
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.subject
power transmission
en_US
dc.subject
Overhead lines
en_US
dc.subject
Overhead transmission lines
en_US
dc.subject
Corona
en_US
dc.subject
Partial discharge
en_US
dc.title
Ion-Flow Environment of HVDC and Hybrid AC/DC Overhead Lines
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
ethz.size
279 p.
en_US
ethz.code.ddc
DDC - DDC::6 - Technology, medicine and applied sciences::621.3 - Electric engineering
ethz.grant
Hybrid HVAC / HVDC overhead lines in Switzerland
en_US
ethz.identifier.diss
24507
en_US
ethz.publication.place
Zurich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02140 - Dep. Inf.technologie und Elektrotechnik / Dep. of Inform.Technol. Electrical Eng.::02632 - Inst. f. El. Energieübertragung u. Hoch. / Power Systems and High Voltage Lab.::03869 - Franck, Christian / Franck, Christian
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02140 - Dep. Inf.technologie und Elektrotechnik / Dep. of Inform.Technol. Electrical Eng.::02632 - Inst. f. El. Energieübertragung u. Hoch. / Power Systems and High Voltage Lab.::03869 - Franck, Christian / Franck, Christian
en_US
ethz.grant.agreementno
153775
ethz.grant.fundername
SNF
ethz.grant.funderDoi
10.13039/501100001711
ethz.grant.program
ethz.date.deposited
2017-10-23T10:42:22Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2017-10-23T11:19:54Z
ethz.rosetta.lastUpdated
2020-02-15T08:15:23Z
ethz.rosetta.versionExported
true
ethz.COinS
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