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Electrical conduction currents of a mineral oil-based nanofluid in needle-plane configuration
KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.ORCID-id: 0000-0002-8173-8765
KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.ORCID-id: 0000-0002-6375-6142
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.ORCID-id: 0000-0003-4774-4341
2016 (Engelska)Ingår i: 2016 IEEE CONFERENCE ON ELECTRICAL INSULATION AND DIELECTRIC PHENOMENA (IEEE CEIDP), IEEE conference proceedings, 2016, s. 687-690Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

We present experiments and simulations on the electrical conduction currents of purified transformer oil with and without surface-modified MgO nanoparticles. Results show that on the injection regime of the voltage-current characteristics, nanoparticles increase the charge production in the fluid. It is also found that the conduction currents in the space-charge-limited regime increased at a lower rate as a function of the voltage in the presence of nanoparticles. The numerical simulations suggest electron attachment is increased due to the nanoparticles, leading to larger accumulation of negative ionic space charge close to the needle in the space-charge-limited regime. It is concluded that electron attachment may be significantly increased with nanoparticles, becoming an important process of electrical conduction in nanofluids.

Ort, förlag, år, upplaga, sidor
IEEE conference proceedings, 2016. s. 687-690
Serie
Conference on Electrical Insulation and Dielectric Phenomena Annual Report, ISSN 0084-9162
Nationell ämneskategori
Elektroteknik och elektronik
Identifikatorer
URN: urn:nbn:se:kth:diva-201297DOI: 10.1109/CEIDP.2016.7785694ISI: 000391639700142Scopus ID: 2-s2.0-85009823702ISBN: 978-1-5090-4654-6 (tryckt)OAI: oai:DiVA.org:kth-201297DiVA, id: diva2:1073970
Konferens
IEEE Conference on Electrical Insulation and Dielectric Phenomena (IEEE CEIDP), OCT 16-19, 2016, Toronto, CANADA
Anmärkning

QC 20170214

Tillgänglig från: 2017-02-14 Skapad: 2017-02-14 Senast uppdaterad: 2019-08-01Bibliografiskt granskad
Ingår i avhandling
1. Pre-breakdown Phenomena in Mineral Oil Based Nanofluids
Öppna denna publikation i ny flik eller fönster >>Pre-breakdown Phenomena in Mineral Oil Based Nanofluids
2019 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Mineral oil is a dielectric liquid commonly used in high voltage equipment such as power transformers. Interestingly, it has been experimentally observed that the dielectric strength of the mineral oil is improved when nanoparticles are added. However, the mechanisms behind these improvements are not well understood, hindering the further innovation process of these so-called nanofluids. This thesis aims to contribute to the understanding of the mechanisms explaining the dielectric strength improvement of the base oil when nanoparticles are added.For this, several experiments and numerical simulations are performed in this thesis. The initiation voltage of electric discharges infive different kind of nanofluids was measured. The large data set obtained allowed to cast experimental evidence on the existing hypotheses that are used to explain the effect of nanoparticles. It is found that hydrophilic nanoparticles hinder the electric discharge initiation from anode electrodes. On the other hand, electric discharge initiation from cathode electrodes was hindered by nanoparticles with low charge relaxation time.The electric currents in mineral oil and nanofluids were also measured under intense electric fields (up to 2GV/m). It is found that the addition of certain nanoparticles increases the measured currents. The possible physical mechanisms explaining the measured currents inmineral oil with and without nanoparticles were thoroughly discussed based on results of numerical simulations. Preliminary parameters used in this thesis to model these mechanisms led to a good agreement between the measured and simulated electric currents.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2019. s. 69
Serie
TRITA-EECS-AVL ; 2019:58
Nationell ämneskategori
Elektroteknik och elektronik
Forskningsämne
Elektro- och systemteknik
Identifikatorer
urn:nbn:se:kth:diva-255605 (URN)978-91-7873-241-8 (ISBN)
Disputation
2019-09-06, Kollegiesalen, Brinellvägen 8, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

QC 20190802

Tillgänglig från: 2019-08-02 Skapad: 2019-08-01 Senast uppdaterad: 2019-08-02Bibliografiskt granskad

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Aljure, M.Becerra, M.Pallon, L. K. H.
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Elektroteknisk teori och konstruktionFiber- och polymerteknologi
Elektroteknik och elektronik

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