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42. On the application of extended grounded slot electrodes to reduce non-circulating bearing currents

Author

Vostrov, Konstantin, Pyrhönen, Juha, Niemelä, Markku, Lindh, Pia, Ahola, Jero, Lappeenrannan-Lahden teknillinen yliopisto LUT, Lappeenranta-Lahti University of Technology LUT, and fi=School of Energy Systems|en=School of Energy Systems

Subjects
electrical discharge machining bearing currents, electrical machines, finite element analysis, induction machines, Ball bearings, variable speed drives
Abstract

Power-electronic-Inverterconverter-induced motor bearing currents are a widespread problem in the field of electrical drives. Parasitic capacitances between the electrical machines parts provide a path for leakage currents, which finally harm the metallic ball bearings. Remembering that end-windings have a significant contribution in building up stray capacitances, a countermeasure affecting both the lamination stack and end winding overhang areas is wantedneeded. The Thiscurrent paper focuses on a countermeasure against the non-circulating bearing currents in the cluster of solutions at the motor side. The eElectrostatic shielding approach, which is a known principle to reduce capacitive couplings, is applied in electrical machines every now and then. In the currentis work, the principle of slot-embedded grounded electrodes is extended to cover also the end-windings. and tThus the electrodes provide a better shaft voltage mitigating effect compared to the case where electrodes are applying applied only inof the approach to the lamination stack area only. The feasibility and effectiveness of such a countermeasure are investigated. Different options in terms of scaling of both the machine size and diameter of the inserted grounded electrodes were analyzed and corresponding conclusions were pointed out. Publishers version

Published
2022

43. On the Application of Extended Grounded Slot Electrodes to Reduce Noncirculating Bearing Currents.

Author

Vostrov, Konstantin, Pyrhonen, Juha, Niemela, Markku, Lindh, Pia, and Ahola, Jero

Subjects
ELECTRODES, MACHINE parts, VARIABLE speed drives, STRAY currents, BALL bearings
Abstract

Power-electronic-converter-induced motor bearing currents are a widespread problem in the field of electrical drives. Parasitic capacitances between the electrical machine's parts provide a path for leakage currents, which finally harm metallic ball bearings. Remembering that end-windings have a significant contribution in building up stray capacitances, a countermeasure affecting both the lamination stack and end-winding areas is needed. This article focuses on a countermeasure against the noncirculating bearing currents in the cluster of solutions at the motor side. The electrostatic shielding approach, which is a known principle to reduce capacitive couplings, is applied in electrical machines every now and then. In this article, the principle of slot-embedded grounded electrodes is extended to cover also the end-windings. Thus, the electrodes provide a better shaft-to-ground voltage mitigating effect compared to the case where electrodes are applied only in the lamination stack area. The feasibility and effectiveness of such a countermeasure are investigated. Different options in terms of scaling of both the machine size and diameter of the electrodes were analyzed and corresponding conclusions were pointed out. [ABSTRACT FROM AUTHOR]

Published
2023
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45. Bothnian Bay Hydrogen Valley – Research report

Author

Karjunen, Hannu, Lassila, Jukka, Tynjälä, Tero, Laaksonen, Petteri, Tuomaala, Mari, Vilppo, Julius, Taulasto, Kimmo, Karppanen, Janne, Laari, Arto, Kosonen, Antti, Ahola, Jero, Lappeenrannan-Lahden teknillinen yliopisto LUT, Lappeenranta-Lahti University of Technology LUT, and fi=School of Energy Systems|en=School of Energy Systems

Subjects
Sähkönsiirto, Electricity grid, Energy infrastructure, Vety, Sähköverkko, Tuulivoima, Wind power, Power transmission, Energiainfrastruktuuri, Hydrogen
Abstract

This report is part of a commissioned research, ordered jointly by Fortum and St1. The re-search was carried out by LUT University between 1.4.2021 – 31.10.2021. The purpose of the study was to perform a hydrogen ecosystem analysis on a strategic level for the Bothnian Bay, describing the key customers, producers, and necessary infrastructural elements. The scope and detail level of the study was purposefully kept light to enable a rapid procedure. A key question of the work was whether local wind power resources would be enough to meet the increased electricity consumption, which was assumed to be escalated primarily by steel decarbonization and power-to-methanol systems. The conclusion of this report is that wind power potential is indeed sufficient for the transition, but extensive capacity additions are nec-essary – not only for the generation, but also for the energy transmission infrastructure. The future electricity demand presented in this work greatly exceeds some of the previously pre-sented national public estimations, which indicates that the prevailing understanding of the opportunities and necessary development actions is deficient. The study found local differ-ences in electricity transmission costs and wind resources, which can lead to competitive dif-ferences, and cause accumulation of investments to specific regions or countries. The results also indicate that chemical storages are likely needed for buffering hydrogen production and storing energy, but further analysis is required to assess the necessary volumes and optimal transport. It is proposed that the analysis is continued in more accurate studies, while also extending the scope to include Norway, Sweden, and Finland in their entirety. Tämä raportti on osa Fortumin ja St1:n tilaustutkimusta. Työ toteutettiin LUT Yliopistolla aika-välillä 1.4.2021 – 31.10.2021. Työn tarkoituksena oli tarkastella strategisella tasolla Peräme-ren alueen vetyekosysteemiä, kuvaten sen oleellisimmat asiakkaat, tuottajat ja vaaditut infra-struktuurielementit. Työn laajuus ja tarkkuustaso oli tarkoituksella kevyehkö nopean läpivien-tiprosessin varmistamiseksi. Eräs työn avainkysymyksistä oli tuulivoimaresurssien riittävyys suhteessa lisääntyneeseen sähkönkulutukseen, johon puolestaan vaikuttaa alueen terästuo-tannon muuttuminen hiilineutraaliksi ja sähköpohjaisten kemikaalien tuotanto (power-to-methanol). Johtopäätöksenä alueen tuulipotentiaalia voidaan pitää riittävänä muutosta varten, mutta käytettävissä olevan kapasiteetin on kasvettava merkittävästi sekä sähköntuotannon että energian siirtojärjestelmien osalta. Työssä esitetyt sähkönkulutuksen ennusteet ylittävät osan aiemmin esitetyistä kansallisista arvioista, jota voidaan pitää osoituksena puutteellisesta näkemyksestä alueen mahdollisuuksien ja kehitystarpeiden suhteen. Tutkimuksessa todetut alueelliset erot tuulisähkön potentiaalin ja sähkönsiirron kustannuksissa voivat heijastua paikal-lisena kilpailuetuna, sekä investointien kasautumisena tietyille alueille ja valtioille. Energian varastointiin ja vedyntuotannon tasaukseen tarvittaneen kemiallisia energiavarastoja, mutta kokoluokan ja kuljetusten tarkempaan arviointiin vaaditaan jatkotutkimuksia. Ehdotamme työn jatkamista tarkemmissa selvityksissä, joissa voidaan myös laajentaa tutkimusaluetta kattamaan Norja, Ruotsi ja Suomi kokonaisuudessaan. Publishers version

Published
2021

49. Power line communication in motor cables of inverter-fed electric drives

Author

Konate, Christophe, Kosonen, Antti, Ahola, Jero, Machmoum, Mohamed, and Diouris, Jean-Francois

Subjects
Powerline networks -- Maintenance and repair, Powerline networks -- Design and construction, Power conditioning -- Models, Business, Computers, Electronics, Electronics and electrical industries
Published
2010

50. Diagnosis tool for motor condition monitoring

Author

Ilonen, Jarmo, Kamarainen, Joni-Kristian, Lindh, Tuomo, Ahola, Jero, Kalviainen, Heikki, and Partanen, Jarmo

Subjects
Fault location (Engineering) -- Research, Induction electric motors -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

In the modern industrial environment there is increasing demand for automatic condition monitoring. With reliable condition monitoring, faults such as mechanical motor failures could be identified in their early stages and further damage to the system could be prevented. Successful monitoring is a complex and application-specific problem, but a generic tool would be useful in preliminary analysis of new signals and in verification of known theories. A generic condition diagnosis tool is introduced in this paper. The tool is based on discriminative energy functions which reveal discriminative frequency-domain regions where failures can be identified. The tool was applied to induction motor bearing fault detection and succeeded in finding characteristic frequencies which allow accurate detection of bearing faults. Index Terms--Condition monitoring, fault detection, Fisher linear discriminant, induction motor, Gabor filters, pattern recognition, signal processing.

Published
2005

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