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Rabuzin, T., Lavenius, J., Taylor, N. & Nordström, L. (2018). Bayesian Detection of Islanding Events Using Voltage Angle Measurements. In: 2018 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids, SmartGridComm 2018: . Paper presented at 2018 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids, SmartGridComm 2018; Aalborg; Denmark; 29 October 2018 through 31 October 2018. IEEE, Article ID 8587561.
Open this publication in new window or tab >>Bayesian Detection of Islanding Events Using Voltage Angle Measurements
2018 (English)In: 2018 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids, SmartGridComm 2018, IEEE, 2018, article id 8587561Conference paper, Published paper (Refereed)
Abstract [en]

The growing presence of distributed generation in power systems increases the risk for the unintentional creation of electrical islands. It is important to apply reliable and quick is landing protection methods. At the same time, the deployment of phasor measurement units facilitates the usage of data-oriented techniques for the development of new wide-area protection applications, one of which is islanding protection. This paper presents a Bayesian approach to detecting an islanding event, which utilizes measurements of voltage angles at the system's buses. A model of mixtures of probabilistic principal component analysers has been fitted to the data using a variational inference algorithm and subsequently used for islanding detection. The proposed approach removes the need for setting parameters of the probabilistic model. The performance of the method is demonstrated on synthetic power system measurements.

Place, publisher, year, edition, pages
IEEE, 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-245971 (URN)10.1109/SmartGridComm.2018.8587561 (DOI)000458801500076 ()2-s2.0-85061060271 (Scopus ID)978-1-5386-7954-8 (ISBN)
Conference
2018 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids, SmartGridComm 2018; Aalborg; Denmark; 29 October 2018 through 31 October 2018
Note

QC 20190314

Available from: 2019-03-14 Created: 2019-03-14 Last updated: 2019-05-10Bibliographically approved
Swati, K., Sarathi, R., Yadav, K. S., Taylor, N. & Edin, H. E. (2018). Corona Discharge Activity in Nanoparticle Dispersed Transformer Oil under Composite Voltages. IEEE transactions on dielectrics and electrical insulation, 25(5), 1731-1738
Open this publication in new window or tab >>Corona Discharge Activity in Nanoparticle Dispersed Transformer Oil under Composite Voltages
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2018 (English)In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 25, no 5, p. 1731-1738Article in journal (Refereed) Published
Abstract [en]

Titania (TiO2) nanoparticles with cetyl trimethyl ammonium bromide (CTAB) surfactant dispersed in transformer oil has higher corona inception voltage than the normal transformer oil, under AC, DC, and composite AC and DC voltages. It is observed that corona inception voltage is lower under composite voltages compared to AC and DC voltages. The corona activity radiates ultra high frequency (UHF) signals with its dominant frequency near 1 GHz. Operating a spectrum analyzer in zero span mode, the UHF signals generated from the corona activity, the number of discharges is observed to be more under composite voltages than under AC voltages, both at inception and at higher voltages. A reduction in interfacial tension and an improvement in flash point is observed in nano-titania with surfactant dispersed transformer oil. The addition of surfactant reduces the turbidity of the nanofluid. Phase Resolved Partial Discharge (PRPD) analysis with UHF signals measured, indicates that corona discharge activity occurs around the peak and the pre-peak rising portions of the supply voltage. It is observed that more discharges occur in the positive half cycle for AC superimposed with positive DC voltage and in the negative half cycle for AC superimposed with negative DC voltage. The magnitude of UHF signals formed due to corona activity is less with nanofluid, irrespective of voltage profiles.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
corona, transformer oil, nanofluid, titania nanoparticles, UHF technique, partial discharge
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-238139 (URN)10.1109/TDEI.2018.007123 (DOI)000446866400020 ()2-s2.0-85054858667 (Scopus ID)
Note

QC 20181108

Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2018-11-08Bibliographically approved
Mahidhar, G. D., Sarathi, R., Taylor, N. & Edin, H. E. (2018). Study on Performance of Silica Nanoparticle Dispersed Synthetic Ester Oil under AC and DC Voltages. IEEE transactions on dielectrics and electrical insulation, 25(5), 1958-1966
Open this publication in new window or tab >>Study on Performance of Silica Nanoparticle Dispersed Synthetic Ester Oil under AC and DC Voltages
2018 (English)In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 25, no 5, p. 1958-1966Article in journal (Refereed) Published
Abstract [en]

Synthetic ester oil (SEO) is becoming a replacement for mineral oil in transformers due to its biodegradability and for its better insulation properties. Silica nanoparticles dispersed in SEO can increase its corona inception voltage (CIV) and breakdown voltage compared to pure SEO. Physico-chemical studies were carried out to understand the characteristics of nanoparticles and nanofluids. Methodical experimental studies were carried out to understand the corona discharge activity in SEO based nanofluid. A ultra-high frequency (UHF) sensor was used to identify corona activity and it is concluded that the UHF signal radiated from corona activity in SEO and nanoparticle dispersed SEO have a bandwidth in the range of 700 MHz to 2 GHz. A comparative study on the CIV of SEO and nanofluid under harmonic AC voltages has been carried out, which indicates a reduction in the CIV as the total harmonic distortion of the supply voltage increases. Phase resolved partial discharge analysis indicates that the magnitude of discharges formed in nanofluid is much lower than in the SEO. Comparative statistical analysis are made with the breakdown voltages of the synthetic ester oil and nanofluid. A comparative analysis on the energy of the UHF signal due to the corona discharges is performed.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
breakdown voltage, corona inception voltage, PRPD, nanofluid, synthetic ester oil, UHF sensor
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-238140 (URN)10.1109/TDEI.2018.007423 (DOI)000446866400046 ()2-s2.0-85054882604 (Scopus ID)
Note

QC 20181108

Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2018-11-08Bibliographically approved
Nikjoo, R., Taylor, N., Edin, H., Hollertz, R., Wåhlander, M., Wågberg, L. & Malmström, E. (2017). Comparison of Oil-impregnated Papers with SiO2 and ZnO Nanoparticles or High Lignin Content, for the Effect of Superimposed Impulse Voltage on AC Surface PD. IEEE transactions on dielectrics and electrical insulation, 24(3), 1726-1734
Open this publication in new window or tab >>Comparison of Oil-impregnated Papers with SiO2 and ZnO Nanoparticles or High Lignin Content, for the Effect of Superimposed Impulse Voltage on AC Surface PD
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2017 (English)In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 24, no 3, p. 1726-1734Article in journal (Refereed) Published
Abstract [en]

Surface discharge behavior of modified oil-impregnated paper (OIP) with nanoparticles (NPs), has been investigated under AC voltage with superimposed impulses. Surface Partial Discharges (PD) can develop at an oil-paper interface and lead to its degradation. Modified paper, made from fibers with adsorbed nanoparticles, can affect the partial discharge behavior of a paper in combination with oil at the interface between oil and fibers. Papers with two different concentrations (2 wt% and 6 wt%) of silica (SiO2), and paper with silanized zinc oxide (ZnO) nanoparticles (1 wt%) have been studied. Papers with SiO2 NPs showed lower impulse-induced surface PD activity. However, thorough purification during the production of SiO2 filled papers was necessary to achieve a good performance. With less purification, paper with 2 wt% of SiO2 did not show such significant improvements. Paper with 6 wt% of SiO2 NPs showed a large number of AC surface PDs, but low influence of impulse voltage on subsequent PD. Papers containing 1 wt% of silanized ZnO showed reduced relative permittivity, but no significant difference in surface PD behavior. The effect of high lignin content in Kraft paper has also been studied. Paper with higher lignin content showed better surface PD characteristics under the impulse. Paper with low concentrations of pure SiO2 NPs, and paper with high lignin content thus appear good candidates for further studies to improve the surface PD behavior of OIP.

Place, publisher, year, edition, pages
IEEE, 2017
Keywords
Nanoparticles, SiO2, silanized ZnO, superimposed impulse, oil-impregnated paper, lignin
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-211614 (URN)10.1109/TDEI.2017.006053 (DOI)000405000300046 ()2-s2.0-85022338626 (Scopus ID)
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy StorageSwedish Energy Agency
Note

QC 201708010

Available from: 2017-08-11 Created: 2017-08-11 Last updated: 2017-08-11Bibliographically approved
Chen, F., Taylor, N., Balieu, R. & Kringos, N. (2017). Dynamic application of the Inductive Power Transfer (IPT) systems in an electrified road: Dielectric power loss due to pavement materials. Construction and Building Materials, 147, 9-16
Open this publication in new window or tab >>Dynamic application of the Inductive Power Transfer (IPT) systems in an electrified road: Dielectric power loss due to pavement materials
2017 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 147, p. 9-16Article in journal (Refereed) Published
Abstract [en]

Inductive Power Transfer (IPT) technology is seen as a promising solution to be applied in an electrified road (eRoad) to charge Electric Vehicles (EVs) dynamically, i.e. while they are in motion. Focus in this study was placed on the dielectric loss effect of pavement surfacing materials on the inductive power transfer efficiency, induced after the integration of the technology into the physical road structure. A combined experimental and model prediction analysis was carried out to calculate this dielectric loss magnitude, based on which some preliminary conclusions as well as a prioritization of future focus needs were summarized in detail.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Pavement materials, Dielectric loss, Inductive Power Transfer, Electric Vehicle
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-210988 (URN)10.1016/j.conbuildmat.2017.04.149 (DOI)000403854100002 ()2-s2.0-85018641699 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme, 605405
Note

QC 20170808

Available from: 2017-08-08 Created: 2017-08-08 Last updated: 2017-08-08Bibliographically approved
Kande, M., Isaksson, A. J., Thottappillil, R. & Taylor, N. (2017). Rotating Electrical Machine Condition Monitoring Automation-A Review. MACHINES, 5(4), Article ID 24.
Open this publication in new window or tab >>Rotating Electrical Machine Condition Monitoring Automation-A Review
2017 (English)In: MACHINES, ISSN 2075-1702, Vol. 5, no 4, article id 24Article, review/survey (Refereed) Published
Abstract [en]

We review existing machine condition monitoring techniques and industrial automation for plant-wide condition monitoring of rotating electrical machines. Cost and complexity of a condition monitoring system increase with the number of measurements, so extensive condition monitoring is currently mainly restricted to the situations where the consequences of poor availability, yield or quality are so severe that they clearly justify the investment in monitoring. There are challenges to obtaining plant-wide monitoring that includes even small machines and non-critical applications. One of the major inhibiting factors is the ratio of condition monitoring cost to equipment cost, which is crucial to the acceptance of using monitoring to guide maintenance for a large fleet of electrical machinery. Ongoing developments in sensing, communication and computation for industrial automation may greatly extend the set of machines for which extensive monitoring is viable.

Place, publisher, year, edition, pages
MDPI AG, 2017
Keywords
condition monitoring, rotating electrical machine, motor fleet, plant-wide
National Category
Reliability and Maintenance
Identifiers
urn:nbn:se:kth:diva-219328 (URN)10.3390/machines5040024 (DOI)000415730400004 ()2-s2.0-85034232859 (Scopus ID)
Note

QC 20171204

Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2017-12-04Bibliographically approved
Chen, F., Taylor, N. & Kringos, N. (2016). Dynamic application of the Inductive Power Transfer (IPT) systems in an electrified road: Dielectric power loss due to pavement materials. Construction and Building Materials
Open this publication in new window or tab >>Dynamic application of the Inductive Power Transfer (IPT) systems in an electrified road: Dielectric power loss due to pavement materials
2016 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526Article in journal (Other academic) Submitted
Abstract [en]

It is well-known that the high cost and limited performance of existing energy storage systems have significantly constrained the commercialization of the Electric Vehicle (EV) at large scale. In recent years, attention has been given not only to the improved energy storage systems but also to develop appropriate charging infrastructures that would allow the EVs to be powered in an easier way. Inductive Power Transfer (IPT) technology, also known as a near-field wireless power transfer technology, is capable of delivering electricity wirelessly with large power and high efficiency at a given gap distance. It is therefore seen as a promising solution to be applied in an electrified road (eRoad) to charge EVs dynamically, i.e. while they are moving. Various technical aspects of this contactless charging solution have been studied actively by system developers, such as the charging power, its efficiency, the optimum gap distance as well safety issues. Focus in this study is placed on the effect of pavement surfacing materials on the wireless power transfer efficiency, after the integration of the technology into the physical road structures. Specifically, a combined experimental and model prediction analysis has been carried out to investigate this potential energy loss in a quantitative way, based on which some preliminary conclusions as well as a prioritization of future focus needs are summarized in detail. This work provides thus an important beginning for understanding the pavement materials’ influence on the IPT systems that may be used for dynamic applications in an eRoad.

Keywords
Road materials, Dielectric properties, Inductive Power Transfer, Electric Vehicle
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-195592 (URN)
Funder
EU, FP7, Seventh Framework Programme, 605405
Note

QC 20161107

Available from: 2016-11-03 Created: 2016-11-03 Last updated: 2017-10-02Bibliographically approved
Wang, X., Taylor, N. & Edin, H. (2016). Enhanced Distinction of Surface and Cavity Discharges by Trapezoid-based Arbitrary Voltage Waveforms. IEEE transactions on dielectrics and electrical insulation, 23(1), 435-443
Open this publication in new window or tab >>Enhanced Distinction of Surface and Cavity Discharges by Trapezoid-based Arbitrary Voltage Waveforms
2016 (English)In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 23, no 1, p. 435-443Article in journal (Refereed) Published
Abstract [en]

Identification of different partial discharge (PD) sources may be improved by the use of non-sinusoidal waveforms of the testing voltages. For instance, surface discharge (SD) and cavity discharge (CD) are not always easy to directly distinguish from the phase resolved PD pattern at traditional 50 or 60 Hz alternating sinusoidal voltage. This study compares PD patterns stimulated by sinusoidal voltage and by several forms of trapezoid-wave voltage, including the limiting cases of triangular and approximately square-wave voltages. Trapezoid-based voltage waveforms are considered as a potential new off-line diagnostic method for PD sources. Partial discharge measurements were performed with each different waveform in two test cells representing canonical cases of SD and CD, with polycarbonate plates as the solid insulating material. The results show that the applied voltage of arbitrary waveform could more clearly distinguish between these PD sources' behavior than normal sinusoidal voltage. The constant-voltage period of peak value in trapezoidal and square voltage waveforms played an important role in the distinction of the two discharge sources. Compared with the cavity discharge's symmetric features, surface discharge produced in the asymmetric test cell shows strong asymmetric behavior during the constant-voltage period between two polarities under trapezoidal and square voltage waveforms. A faster rise time and increased duration of the constant peak-voltage part of the waveform caused more obvious asymmetry of the surface discharge.

Keywords
Surface discharges, cavity discharge, arbitrary testing voltages, distinction, asymmetric
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-185387 (URN)10.1109/TDEI.2015.005236 (DOI)000372400600054 ()2-s2.0-84963839194 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 20160418

Available from: 2016-04-18 Created: 2016-04-18 Last updated: 2017-11-30Bibliographically approved
Lyne, A. L., Taylor, N., Jaeverberg, N., Edin, H. & Birgisson, B. (2016). Low frequency dielectric spectroscopy of bitumen binders as an indicator of adhesion potential to quartz aggregates using Portland cement. Materials and Structures, 49(4), 1327-1336
Open this publication in new window or tab >>Low frequency dielectric spectroscopy of bitumen binders as an indicator of adhesion potential to quartz aggregates using Portland cement
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2016 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 49, no 4, p. 1327-1336Article in journal (Refereed) Published
Abstract [en]

The purpose of this investigation was to interpret the bitumen-aggregate adhesion based on the dielectric spectroscopic response of individual material components utilizing their dielectric constants, refractive indices and average tangent of the dielectric loss angle (average loss tangent). Dielectric spectroscopy of bitumen binders at room temperature was performed in the frequency range of 0.01-1000 Hz. Dielectric spectroscopy is an experimental method for characterizing the dielectric permittivity of a material as a function of frequency. Adhesion data has been determined using the Rolling bottle method. The results show that the magnitude of the average tangent of the dielectric loss angle (average loss tangent) depends on bitumen type. The average loss tangent in the frequency range 0.01-1 Hz is introduced as a potential indicator for predicting polarizability and, thereby, adhesion potential of bitumen binders to quartz aggregates when using Portland cement. In order to obtain acceptable adhesion of 70/100 penetration grade bitumen binders and quartz aggregates when using Portland cement, it is suggested that the binder have an average tan delta > 0.035 in the frequency range 0.01-1 Hz.

Place, publisher, year, edition, pages
Springer Netherlands, 2016
Keywords
Bitumen, Quartz, Portland cement, Dielectric constant, Permittivity, Average loss tangent, Polarizability
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-186641 (URN)10.1617/s11527-015-0579-5 (DOI)000373963700018 ()2-s2.0-84924559587 (Scopus ID)
Note

QC 20160601

Available from: 2016-06-01 Created: 2016-05-13 Last updated: 2017-11-30Bibliographically approved
Chen, F., Taylor, N., Kringos, N. & Birgisson, B. (2015). A study on dielectric response of bitumen in the low-frequency range. Paper presented at 6th Conference of the European Asphalt Technology Association (EATA),Stockholm, Sweden, 15-17 June 2015.. International Journal on Road Materials and Pavement Design, 16, 153-169
Open this publication in new window or tab >>A study on dielectric response of bitumen in the low-frequency range
2015 (English)In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 16, p. 153-169Article in journal (Refereed) Published
Abstract [en]

From the current state of literature, the dielectric property of bitumen has not been understood extensively, nor its relation with other properties such as polarity and rheology. In this study, dielectric spectroscopy measurement in a low-frequency range (10−2–106 Hz) was performed on both pure bitumen in different grades and wax-modified bitumen (WMB). From the performed tests we found the following: (i) the dielectric response of base bitumen is strongly temperature and frequency dependent, which is also highly linked to the rheology of the system. (ii) No remarkable differences in the dielectric constant (Formula presented.) among different grades of bitumen from the same crude oil source can be seen. (iii) Regular changes of dielectric loss tangent (tan δ) among the different grades of bitumen can be observed, which can be a good indicator for the linkage between the dielectric and rheological responses. In addition, it can also be perceived that the dielectric spectroscopy may have the potential to become a new approach for the multi-scale characterisation of road infrastructure materials.

Place, publisher, year, edition, pages
Taylor & Francis, 2015
Keywords
Dielectric Spectroscopy, Bitumen, Electrical Polarization, Rheology
National Category
Civil Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-163549 (URN)10.1080/14680629.2015.1029682 (DOI)000355122400010 ()2-s2.0-84929943889 (Scopus ID)
Conference
6th Conference of the European Asphalt Technology Association (EATA),Stockholm, Sweden, 15-17 June 2015.
Note

QC 20150616. Updated from accepted to published.

Available from: 2015-04-07 Created: 2015-04-07 Last updated: 2017-12-04Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0759-4406

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