PhD projectsDepartment of Electric Power Engineering
May 2016
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Postadresse: Besøksadresse: Telefon +47 73 59 42 10
N-7491 Trondheim O. S. Bragstads pl..2E, Telefaks +47 73 59 42 79
http://www.ntnu.no/elkraft N-7034 Trondheim
An overview over PhD Projects 2016 at
Department of Electric Power Engineering
Faculty of Information Technology, Mathematics and Electrical Engineering
Norwegian University of Science and Technology
This report gives an overview of current PhD research projects at the Department of
Electric Power Engineering.
Currently 28 students are registered in our PhD program. This number is now peaking
after a steady growth for several years, reflecting the increased general interest in
energy and electric power from renewable resources. The department has 11 professors,
4 associate professors, and 6 adjunct professors. The number of Postdocs has increased
the last few years from four to ten. In addition to the scientific and administrative staff,
the department houses a mechanical workshop and an electro technical laboratory.
The research activity at the Department is mainly covered by the research topics of our
two groups:
Power Systems
Power Technology
The PhD projects presented here focus on topics from broad range of research areas
with electric power engineering. The research projects are both theoretical and practical
and based on extensive use of our computer and laboratory resources. The projects are
also influenced by our collaboration with industry and our neighbour institution
SINTEF Energy Research AS. Since the PhD projects represent the main part of the
professors’ research, this folder also gives a good overview of the entire research
activity at the Department.
The nominal duration of PhD program is three years of full-time research, of which a
half year is devoted to post graduate courses. A typical PhD project, however, lasts up
to four years, where the additional time is booked within university/educational duties.
For further information about the research projects presented, please contact the
individual researcher given by name in this folder.
NTNU, November 2016
Magnus Korpås (sign)
Professor
Coordinator of the PhD programme
Phd summary 2016
Name Title
Supervisor p
Aakre, Torstein Grav
Condition assessment of generator insulation Erling Ildstad 1
Abid, Fahim Current interruption in supercritical N2 Kaveh Niayesh 2
Acharya, Anirudh Budnar
Dynamic Modelling and Control of Power Electronic Energy Conversion System
Lars Norum 3
Bødal, Espen Flo Hydrogen Production from Wind- and Hydro Power Magnus Korpås 5
Elahidoost, Atousa Model Based Design for the Topology Optimization of HVDC Grids
Elisabetta Tedeschi
7
Endegnanew, Atsede Gualu
Stability and control of multi-terminal HVDC transmission
Kjetil Uhlen 8
Engevik, Erlend L. Design of variable speed generators for hydropower applications
Arne Nysveen 9
Graabak, Ingeborg Balancing of wind and solar power production in Northern Europe with Norwegian hydropower
Magnus Korpås 10
Hjelmeland, Martin N.
Integrating balancing markets in hydropower scheduling models
Magnus Korpås 11
Håberg, Martin Exchange of Standard Products for Electricity Balancing in the European Power Marke
Magnus Korpås 13
Håkonseth, Gunnar Breakdown mechanisms and electric field in mass impregnated high voltage direct current cables
Erling Ildstad 15
Jakobsen, Sigurd Hofsmo
Power system model validation using ambient data Kjetil Uhlen 16
Kalemba, Lester ASPECTS OF MULTIVARIABLE CONTROL IN POWER SYSTEMS - Control Design and Coordination
Kjetil Uhlen 17
Kantar, Emre Characterization of Electrical Breakdown Strength of Dielectric Surfaces
Erling Ildstad 19
Kiel, Erlend Sandø Methods for understanding and communicating uncertainties and risk related to extraordinary events
Gerd Hovin Kjølle
22
Kristiansen, Martin Adequate modelling of Transmission Expansion Planning
Magnus Korpås 23
Löschenbrand, Markus
Optimization of Hydro Power Units on multiple Short Term Markets
Magnus Korpås 24
Meyer, Hans Kristian Hygen
Dielectric barriers under lightning impulse stresses Frank Mauseth 26
Nejati Fard, Razieh Electric Power System Design for Deep-Sea Mining Applications
Elisabetta Tedeschi
27
Pandakov, Konstantin
Protection of power systems with distributed sources Hans Kristian Høidalen
28
Rabuzin, Tin System Integration and Performance
Hans Kristian Høidalen
29
Ranaweera, Iromi Energy storage for control of distributed photovoltaic systems in the smart grid
Ole-Morten Midtgård
30
Spro, Ole Kristian Design og GaN converter for inductive charging applications
Ole-Morten Midtgård
31
Taffese, Abel Assegid
Modelling and Control of High Voltage DC-DC Converters
Elisabetta Tedeschi
33
Taxt, Henning Ablation-assisted current interruption in MV switchgear
Kaveh Niayesh 34
Tiwari, Sughadra Design Principles for Optimal Use of Wide Bandgap Power Semiconductors
Ole-Morten Midtgård
35
Zaferanlouei, Salman
Integration of Electric Vehicles with Smart Grid Magnus Korpås 36
PhD graduated from 2000 37
Torstein Grav Aakre
Home Country: Norway
Year of Birth: 1988
Email: [email protected]
Home Page: www.ntnu.no/employees/torstein.aakre
Master Degree: MSc Applied Physics and Mathematics
University: NTNU
Graduation Year: 2013
Supervisor: Erling Ildstad
Research Group: Electric Power Technology
Co-Supervisor(s): Sverre Hvidsten and Arne Nysveen
Project: Hydrogenerator Stator Winding Insulation Assessment
Condition assessment of generator insulation Hydropower generators are the main source of electrical power in Norway. The large development of hydropower generators in Norway were performed in the middle of the 20th century. Recent reports
claim that 18 – 58 % of these hydropower generators have increased uncertainty with respect to failure and need replacement. Additionally, new and tougher usage patterns with rapid starts and stops challenge the insulation beyond what it was designed for. In order to avoid unnecessary replacement of the generator, condition assessment is more important so that the replacement happens closer to the end of life. The main purpose of this PhD work is to facilitate better criteria for condition assessment of hydropower generator insulation by establish relations between measured parameters and the physical condition of generator insulation. One important objective for this PhD work is to develop techniques to detect premature electric failures. To do so, the PhD work must explain how different defects severity respond to different techniques. The main part of the PhD work will be experimental and should investigate how different measurement techniques work to reveal different deteriorations. Different deteriorations will be introduced to the insulation and examined under different conditions, voltage and frequency. This will form the foundation to create relations between measured parameters and the degradation caused by the deterioration. Numerical simulations will be performed supplementary to support the experimental results in the analysis. The discussion of the results will combine theory, numerical simulations and experimental results to form a model that describes the deterioration mechanisms. From this, it should be possible to see trends, form relations between the measured parameters and the physical condition of generator insulation. The required sensitivity of the experiments should also be discussed. The final discussion should explain the condition of the insulation. This work will deal with answering the following questions experimentally and by a literature survey:
1. How do generator insulation fail? 2. How is condition assessment performed today and how can it be improved? 3. How can the rate of ageing be measured?
4. How are the best evaluation criteria for condition assessment justified?
1
Fahim Abid
Home Country: Bangladesh
Year of Birth: 1990
Email: [email protected]
Home Page:
http://www.ntnu.edu/employees/fahim.abid
Master Degree: Electrical Engineering
University: KTH Royal Institute of Technology
Graduation Year: 2015
Supervisor: Kaveh Niayesh
Research Group: Power Technology
Co-Supervisor(s): Magne Runde
Project: Novel Current interruption technology
Current interruption in supercritical N2 Although SF6 is widely used in circuit breaker for its superior arc extinguishing capability, it is
classified as a potent greenhouse gas with a very high global warming potential. Supercritical
fluid, which is formed above critical temperature and pressure, shows physical properties of
liquids (insulation strength, thermal behavior) and gases (self-healing, high fluidity, absence
of vapor bubbles) which are crucial as arc interruption medium.
Main goal of this PhD research is
to understand the arc interruption
phenomenon in supercritical N2.
Nitrogen is chosen for its low
critical temperature (126 K) and
pressure (33.5 bar) and its benign
nature to the environment.
Objective includes designing and
realization of ultra-high pressure
test chamber, followed by
experimental investigations
regarding arc extinction.
This is a completely a new area to explore, hence it comes with additional challenges and risks.
However, it has the potential to be used as an insulation material for subsea applications
where the pressure is already high and depending upon the arc voltage characteristics it might
be a solution for HVDC breakers, hence it is important both technically and strategically. Final
stage of the project includes modelling backed by experiments investigations.
2
Name
Home Country: Anirudh Budnar Acharya
Year of Birth: 13-06-1985
Email: [email protected]
Home Page:
Master Degree: MSc (Engg)
University: Indian Institute of Science,
Bangalore
Graduation Year: 2011
Supervisor: Lars E Norum
Research Group: Power Systems
Co-Supervisor(s): Dimosthenis Peftitsis
Project: Dynamic Modelling and Control of Power Electronic Energy Conversion Systems
Dynamic Modelling and Control of Power Electronic Energy Conversion
Systems The power electronics converters, referred as converters, are made of semiconductor power switches
arranged in a specific method to achieve the desired power conversion. These converters act as an
interface between different energy sources and loads- active or passive. While the structure of power
electronics converters enables the connection between different types of source and load, the control
plays a vital role in effective interaction.
In order to have an effective control system the knowledge of dynamic (physical) behavior of the source,
the load and the power electronic converter involved are essential. The converters generally are non-
linear due to switching behavior. The control of such converters, therefore, are either non-linear or
linearized with certain assumptions.
The controllers used for control of power converters are digital systems, with few exceptions. The
present day digital controller are much faster and reliable compared to their predecessors. Due to these
advances in digital controllers, sophisticated control algorithms can be implemented for superior
performance of overall system.
The project will study the impact of converting a continuous model of the system into discrete time
domain with respect to various system and controller parameters. Explore new techniques to control the
power converter for ease of implementation in digital controllers. The Modular Multilevel Converter
(MMC), Figure 1, is chosen for investigating the integration of energy sources, Photovoltaic (PV) array
and battery, to LV power grid. Methods to interface the PV and battery to MMC topology and control
methods to address the problems associated with such system will be explored. Methods for fault
diagnostics of PV and MMC will be developed. The control methods will be validated with laboratory
experiments.
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Figure 1: Modular Multilevel Converter interfaced to renewable energy sources (a) without isolation in case of PV module
(b) With isolation in case of PV string or array
4
Name: Espen Flo Bødal
Home Country: Norway
Year of Birth: 1992
Email: [email protected]
Home Page: www.ntnu.no/ansatte/espen.bodal
Master Degree: Energy and Environmental Engineering
University: NTNU
Graduation Year: 2016
Supervisor: Magnus Korpås
Research Group: Power Systems
Co-Supervisor(s): Petter Nekså
Project: Hyper
Hydrogen Production from Wind- and Hydro Power The PhD is a part of the Sintef project “Hyper”, which studies production of hydrogen from
natural gas through steam methane reforming (SMR) with carbon capture and storage (CCS)
and wind- and hydro power through electrolysis of water. These types of systems are
interesting in order to take advantage of the large gas resources without producing CO2
while simultaneously developing renewable energy resources restricted by low transmission
capacity. This PhD focuses mainly on the electric part of the system, including electrolyser,
hydrogen gas storage, grid, wind- and hydro power.
Several models will be developed for component sizing and operation as well as studying the
local and regional effects of variable hydrogen production on the power system. The
regional models will include existing hydro power, grid constraints and options for
construction of new wind power at other locations in the power system in addition to the
bus where hydrogen is produced. Both deterministic and stochastic models are planned to
be developed, considering both technical and economic aspects of the system.
The models will be tested in several case studies based on relevant real-world cases where
undeveloped renewable energy sources and natural gas is present, for example in the region
surrounding the natural gas facilities at Hammerfest in Northern Norway. The Northern
Norway case is especially interesting as low transmission capacity is restricting development
of promising wind energy resources in the region. Some prospected scenarios hydrogen
production includes an initial 90/10 ratio of from natural gas and wind and hydro power
respectively with a later expansion to a 70/30 production ratio.
5
Figure 1: Illustration of a system with hydrogen production from natural gas and wind- and hydro power, including a regional representation of the power system with constrained transmission- lines(red).
6
Atousa Elahidoost Home Country: Iran
Year of Birth: 1985
Email: [email protected]
Home Page:
http://www.ntnu.edu/employees/atousa.elahidoost
Master Degree: Electric Power Engineering
University: NTNU
Graduation Year: 2016
Supervisor: Elisabetta Tedeschi
Research Group: Electric Power Systems
Co-Supervisor(s): Maider Santos - Mugica
Project: IDeCON
Model Based Design for the Topology Optimization of HVDC Grids The global tendency towards the implementation and improvement of the Distributed Energy Resources (DER), especially renewables, in response to realization of smart grid policy is extensively growing in recent years. Motivation for integration of renewables into global energy network is not only to meet the ever increasing energy demand but also to improve the energy availability, reliability, security and quality as well as to compensate the adverse impact of fossil fuels and nuclear energy on global warming. Among different renewables, offshore wind farm has attracted considerable attention mainly in Europe due to its geographical feasibility especially in the North Sea. HVDC grids are considered to be the best solution to transmit large amounts of wind power, in particular from offshore application to the land power system; in fact, HVDC networks are going to be an inevitable part of smart grids since they are the most reasonable alternative where long distance transmission networks or submarine cable routes are required.
This PhD project as a part of IDeCON research project is intended to focus on design and control of offshore HVDC networks, and the main aim is to provide a comprehensive guideline for design and modeling of offshore HVDC grids while utilizing optimization methodologies and including control constraints, to satisfy initial design considerations. The study should offer solutions not only for design and development of new HVDC grids from scratch but also it needs to cover strategies for expansion of currently existing networks. Besides, it is intended to extend the model from point-to-point topology to radial and multi-terminal configuration and further into meshed networks. The most significant challenge through development of the models is to reassure the stability of the system under steady-state and transient conditions while taking into account, for example, the techno-economics and environmental considerations. Therefore, there is a demand for implementation of multi-layered control strategies comprising optimization constraints. In fact, the topology optimization should not only be limited to equipment level, and it needs to be so comprehensive to embrace the entire system.
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Name: Atsede Gualu Endegnanew
Home Country: Ethiopia
Year of Birth: 1986
Email: [email protected]
Home Page:
http://www.ntnu.no/ansatte/atsede.g.endegnanew
Master Degree: Msc in electric power engineering
University: The Norwegian University of Science and
Technology
Graduation Year: 2010
Supervisor: Kjetil Uhlen
Research Group: Power Systems
Co-Supervisor(s): Salvatore D’Arco
Project: OffshoreDC
Stability and control of multi-terminal HVDC transmission
Multi-Terminal High Voltage Direct Voltage (MTDC) grids are expected to play a vital role in the
integration of large-scale far offshore wind power plants and interconnection of large asynchronous
power systems. Extensive research has been conducted on the operation and control of MTDC grids in
the last decade. Although the introduction of MTDC grids will eventually result in hybrid ac/dc power
systems, the focus has been mostly on DC grids with ac grids modelled as constant voltage sources. This
PhD research work aims at addressing this lacuna.
The PhD work focuses on the dynamic behavior of hybrid ac/dc power systems where multiple
asynchronous ac grids are connected to a common MTDC grid. It studies interaction of ac and dc
grids, and coupling of ac system dynamics through MTDC systems. The objective of the PhD include:
- develop a linear model of a generalized system that includes both MTDC and detailed multi-
machine models in order to get full picture of the ac/dc and ac/ac dynamic interaction
- study how ac grids are affected by the introduction of the MTDC grids and the control
methods implemented in the converter controllers
- investigate interactions between the electro-mechanical modes of synchronous generators
across the dc system
- understand and model the nature of dynamic interactions between asynchronous grids
connected through MTDC systems
- explore possible adverse interactions between asynchronous ac grids
8
Erlend L. Engevik
Home Country: Norway
Year of Birth: 1990
Email: [email protected] /[email protected]
Home Page: www.researchgate.net/profile/Erlend_Engevik
Master Degree: Energy and environmental engineering
University: NTNU
Graduation Year: 2014
Supervisor: Arne Nysveen
Research Group: Power Technology
Co-Supervisor: Robert Nilssen
Project: Norsk vannkraftsenter (NVKS)
Design of variable speed generators for hydropower applications
The power system is experiencing an increasing share of electric power production that comes from intermittent power sources like wind and solar energy. Increased pressure is put on controllable power sources like hydropower to deal with fluctuations in the output of electric power production. Generators used in hydropower plants today are not designed and optimized for frequent changes in active power production. The main purpose of this work is to develop optimum synchronous generator designs where the speed of rotation and electrical frequency is allowed to vary within given intervals. Results indicates that the highest efficiency is achieved at low nominal frequencies, while
generator weight is reduced substantially at higher nominal frequencies. Cost optimization
where both losses and use of materials are taken into account indicates that a nominal
frequency around 50 Hz will achieve the lowest total cost. There are also cost benefits
associated with increasing the maximum values of the synchronous reactance, but this does
also cause several possible design issues that will have to be resolved.
9
Ingeborg Graabak Home Country: Norway Year of Birth: 1962 Email: [email protected], [email protected] Home Page: Master Degree: MSc , Engineering Cybernetics, 1986 University: NTNU
Supervisor: Magnus Korpås Research Group: Electric Power Systems Co-Supervisor(s): Project: HydroBalance
Balancing of wind and solar power production in Northern Europe with
Norwegian hydropower
The European power system is expected to gradually increase its share of production from variable
resources like wind and solar and to phase out production which generates emission of greenhouse
gases. In periods with limited production from the wind turbines and the solar plants, demand has to
be covered from other types of production. In other periods the production from wind and solar plants
may exceed the demand and the energy can be stored for future use. Norway has approximately half
of the hydro power reservoir capacity in Europe, and the Norwegian power system can provide Europe
with some of the future needed flexibility. By further developing the Norwegian system, e.g including
more pumping capacity, the value of the power system will probably increase.
The PhD will assess cost-efficient storage configurations for various scenarios of renewable and
thermal power generation, and analyse how such configurations perform in the power market. A
scheme will be developed to systematically categorize variability and the need for storage for
different time horizons in a multiple coupled market environment. This scheme will be used to
establish scenarios with different storage options to be further analysed by simulations. As
alternative to storage, the flexibility of demand and thermal generation should be included on the
overall balancing needs assessment. The work include:
- Establish data models with sufficient spatial and temporal resolution.
- Assess the need for storage in different time perspectives, depending on scenarios of
thermal and hydro generation capacity and its technical capabilities, particularly ramping
speed. The essence is to look at characteristic periods for different scenarios of included
intermittent generation (Wind, PV) and identify the flexibility of the thermal generation,
hydropower generation, other storage options and loads. It will be assumed a regional
description where major transmission capacities are included to capture the generation and
load composition in the different regions.
- Compare alternative solutions for storage and other flexibility assets, both in economic terms
and with respect to physical power system related results, considering different scenarios.
10
Martin N. Hjelmeland
Home Country: Norway
Year of Birth: 1990
Email: [email protected]
Master Degree: Electric power engineering
University: NTNU
Graduation Year: 2015
Supervisor: Magnus Korpås
Research Group: Power systems
Co-Supervisor(s): Arild Helseth, Gerard Doorman
Project: IBM project at SINTEF Energy Research
Integrating balancing markets in hydropower scheduling
models
Background
In the EU there are ambitious targets for increasing the renewable electricity generation,
especially wind- and solar-power. Increased renewable power supply can reduce the need for
fossil-fuel power generation, and in this way reduce Europe's CO2-emissions. A challenge is
however that the renewable power generation varies a lot depending on weather conditions,
while power generation must be equal to consumption every second to avoid system-
breakdown. The needed supply from other types of generation (e.g. gas-power) in one given
hour is therefore tuned-in through several market-types: day-ahead, intra-day, balancing and
capacity remuneration. However, the institutional arrangements vary from country to country.
Hydropower scheduling models are vital for achieving an optimal utilization of water stored
in reservoirs. The high percentage of flexible hydropower generation in Norway has led to
low volumes in the reserve markets, thereby little focus on developing models for generation
in multiple markets. Recent year's developments in both the political and energy sector, with
stronger interconnections in the transmission grid and growing renewable generation, has led
the energy producers to evaluate other markets for their electricity supply.
The increasing need for balancing-services in Europe is also a major business-opportunity for
Norwegian producers. Should a hydropower producer supply for the spot market as
traditionally, or is there a major benefit from being active in all the above-mentioned market-
types? This thesis has this by designing and running case studies for a local hydropower
system.
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Research
In previous work [1], a combined Stochastic Dynamic Programming (SDP)/SDDP method was
extended to incorporate sales of capacity reserves, and applied together with a simulator. The purpose
of the work was to quantify the influence a capacity reserve market has on the medium-term
hydropower scheduling, considering accurate modelling of the physical system. The work showed that
the SDP/SDDP model overestimated the amount of available capacity by 27% compared to the
Simulator Model. It should be noted that these results assumes that the hydropower owner is a price-
taker in the capacity reserves market. This assumption is questionable considering the low volumes in
this market. The results can therefore be seen as an upper limit to the true value.
In [2], we investigated how capacity reserves prices would be influences by increasing amounts of
wind penetration in the system, and how well hydropower is equipped to incorporate non-dispatchable
generation.
Ongoing research is investigating how non-convexities, such as a unit commitment, may be included
in the problem.
References
[1] M. N. Hjelmeland, M. Korpås og A. Helseth, «Combined SDDP and simulator model for
hydropower scheduling with sales of capacity,» i 2016 13th International Conference on the
European Energy Market (EEM), 2016.
[2] M. N. Hjelmeland et al., «Provision of Rotating Reserves from wind power in a hydro-dominated
power system,» i 2016 International Conference on Probabilistic Methods Applied to Power
Systems (PMAPS), 2016.
Figure 1: Overview of a power system with hydropower, wind power, thermal
generation, load and import/export possibilities.
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Martin Håberg
Home Country: Norway
Year of Birth: 1991
Email: [email protected]
Home Page: ntnu.edu/employees/martin.haberg
Master Degree: Energy and Environmental
Engineering
University: NTNU
Graduation Year: 2015
Supervisor: Gerard Doorman
Research Group: Power Systems
Co-Supervisor(s): Magnus Korpås
Project: Industrial PhD
Exchange of Standard Products for Electricity Balancing in the
European Power Market The increasing penetration of generation from renewable sources and the introduction of
Standard Products for exchange of balancing energy are only some of the factors calling for
more sophisticated means of electricity balancing. This doctoral work investigates the
Balancing Energy Activation Problem (BEAP) from the perspective of the Transmission
System Operator (TSO). This includes assessing technical and economic factors influencing
activation decisions, as well as analyzing the optimization problem of optimally activating
Frequency Restoration Reserves (FRR). Development and comparison of formulations and
solution methods for BEAP will contribute to new knowledge within the field of power
system operation and very short-term generation scheduling under uncertainty.
An important part of the PhD research will be to develop new and efficient optimization
algorithms for the BEAP. As a prerequisite, research will be conducted within the topics of
imbalance forecasting, Standard Products and balancing philosophies. Combined with
existing models, the optimization algorithms also allow for a better quantification of the
impact of integrating European balancing markets. A decision support tool based on the
optimization and forecasting algorithms will be developed, providing insight and advice to
Norwegian TSO
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Statnett and ENTSO-E on how to balance the power system more efficiently. The research
and analysis work will be carried out in close cooperation with Statnett, where the candidate
is employed.
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Gunnar Håkonseth Home Country: Norway Year of Birth: 1985 Email: [email protected] Home Page: www.ntnu.no/ansatte/gunnar.hakonseth
Master Degree: Applied physics and mathematics University: NTNU Graduation Year: 2011
Supervisor: Erling Ildstad Research Group: Power Technology Co-Supervisor(s): Frank Mauseth (NTNU) and Knut Magne Furuheim (Nexans Norway AS) Project: Mass impregnated non-draining HVDC submarine cables
Breakdown mechanisms and electric field in mass impregnated high voltage direct current cables High voltage direct current (HVDC) cables transfer electric energy across large distances, particularly across straits and seas. HVDC cables are considered important to “the green shift”, where large amounts of electric energy are to be consumed far away from where it is produced. The most mature type of HVDC cables is mass impregnated non-draining (MIND) cables. Such cables are insulated with paper strips that are impregnated with viscous oil (“mass”).
The aim of the project is to contribute to better understanding of the electric insulation of MIND cables. The motivation for this is to achieve a basis for design improvements so that MIND cables can be made either with greater capacity (in terms of current or voltage) or with less use of raw materials.
The main questions to be answered are:
- How do the conductivity, partial discharge (PD) activity, breakdown mechanisms and breakdown strength of the insulation vary with temperature and external pressure?
- How is the local electric field in different parts of the insulation at various load condition?
These questions are closely related to each other, as a thorough understanding of the conductivity is a key to assessing the electric field.
Cavities, which are bubbles of evaporated mass at low pressure, can arise in the insulation as a result of thermal contraction of the impregnating mass when little or no current flows through the conductor. Such cavities can be detrimental for the cable, since both the electric field and the breakdown strength in cavities deviate from other parts of the insulation. It is planned to study both fully impregnated insulation and the effect of cavities.
The PhD candidate is employed by Nexans Norway AS.
15
Sigurd Hofsmo JakobsenHome Country: Norway
Year of Birth: 1989
Email: [email protected]
Home Page: http://www.ntnu.edu/employees/sigurd.h.jakobsen
Master Degree: MSc Electrical engineering
University: NTNU
Graduation Year: 2013
Supervisor:
Research Group: Kjetil Uhlen
Co-Supervisor(s):
Project: Operation of the Smart Grid with Wide Area Information (OperaGrid)
Power system model validation using ambient data Transmission system operators rely on both offline studies and online monitoring of the
power system to operate it in a secure manner. However, for this approach to work, accurate
simulation models and monitoring approaches are needed. One can easily find examples in
the literature where at least one of these aspects have not been sufficiently met.
Inherently both the problem of inaccurate models and inadequate situational awareness can
be reduced by better monitoring of the system. For instance in the case of the 1999 Western
System Coordinating Council (WSCC) blackout measured data from the system was used to
update the simulation models. Traditionally, the models have been constructed from the
name plate information or by performing tests on the components under study. With the
introduction of more advanced measurement systems such as phasor measurement units
(PMUs) it is now possible to both observe and construct models online. This is of great
interest since the components under study are often not owned by the TSOs such as the
generators. However, there are some potential shortcomings with PMU data due to the
sampling frequency and the energy level of ambient PMU data. This leads to the following
questions:
• For what applications are models obtained using ambient PMU data valid for different
energy levels of the ambient signal?
• What is the confidence interval of the obtained parameters as a function of the measured
signal?
• What is the system operator’s benefit of automatically online model validation compared
to values reported prior to operation?
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Lester KalembaHome Country: ZambiaYear of Birth: 1976Email: [email protected]: www.ntnu.edu/employees/lester.kalembaMaster Degree: MSc Electric Power Engineering, 2011University: NTNU
Supervisor: Professor Kjetil UhlenResearch Group: Electric Power SystemsCo-Supervisor(s): Professor Morten HovdProject: Optimal Power Network Design and Operation
“ASPECTS OF MULTIVARIABLE CONTROL IN POWER SYSTEMS - Control
Design and Coordination”
ABSTRACT: Power systems, around the world, are constantly changing. This change is mainly drivenby: (i) Climate policy, which in turn stimulates the development and integration of Renewable EnergySources (RES) such as wind generation; (ii) Technological developments, such as: improvements inmeasurements using phasor measurement units, which has created a whole range of new possibilitiesfor system operation and control; and improvements in HVDC technology; (3) Market integration, witha drive towards a common operation framework among several countries.
To ensure secure operation of these increasingly stressed systems, the provision of adequate levels ofcontrol, such as damping for electromechanical modes of oscillation, is necessary. The developmentof controllers that embrace multiple inputs for augmented system performance is, therefore, an areaof great interest. Moreover, synchrophasor technology provides the possibility for widely dispersedsignals, in a power system, to be centralized, processed and distributed in real time. This PhD Researchproject focuses on the design and coordination of multivariable controllers for augmentation of powersystem stability. Both linear and nonlinear techniques are applied to develop controllers for FACTS andsynchronous generators.
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Figure 1: Location of Multiple Power System Stabilizers (PSS)
Figure 2: Interaction among the Power System Stabilizers at critical oscillation frequencies
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Project Description
Emre Kantar
Home Country: Turkey
Year of Birth: 1988
Email: [email protected]
Home Page: http://www.ntnu.edu/employees/emre.kantar
Master Degree: Power Electronics and Motor Drives in
Electrical and Electronics Engineering, 2014
University: Middle East Technical University (METU)
Supervisor: Prof. Erling Ildstad
Research Group: Electric Power Technology
Co-Supervisor: Associate Prof. Frank Mauseth
Project: High Voltage Subsea Connections
Characterization of Electrical Breakdown Strength of Dielectric
Surfaces
Introduction
Cost effective and reliable power supply systems are key elements in the success of subsea processing and
flow assurance systems. Cable terminations and connectors constitute very critical components in the power
supply system and the majority of direct failures are related to such components. Installation and
maintenance of the main components in a power supply system (motors, transformers, switchgears, VSD’s
etc.) require flexibility and modularity and hence they are dependent on interfaces to wet mateable
connectors. In some cases, total system design is dictated by availability of connector technology. On this
basis, reliable high voltage/high power wet mateable connectors are of vital importance for future subsea
extension. The future requirement for oil and gas production pushes the requirements for subsea connections
towards; higher voltage levels (longer step outs and subsea compression), higher power ratings (subsea
compression and flow assurance systems like DEH, IH and PIP), higher temperatures (downhole and flow
assurance applications), deeper waters, and DC or low frequency AC (longer step-outs and subsea
converters).
There is still a big gap between technology need and available technology as the components are taken into
use at higher temperatures and voltage levels. The equipment shall operate under conditions (pressure,
temperature, voltage and chemical environment) where such equipment never before has been applied. If
such systems shall be developed for reliable subsea installations, several technological improvements with
respect to both electrical insulation materials and systems have to be achieved. Today only wet-mate
connectors rated for 12 kV are field proven. Wet-mate connectors for 36 kV are available from several
manufacturers. It has been dictated by the massive companies in this area that connectors rated for 150 kV
should be available within the next decade. Conventional materials are possibly not suited for high voltage
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subsea connectors and penetrators, and for alternative new materials there is a lack of experience and test
results. There is a need for knowledge of what type of insulation material that can withstand the combined
action of high voltages and relevant environmental conditions.
For subsea high voltage connectors and penetrators there are particular concerns about mechanical and
electrical design. On the mechanical side the main challenges are water ingress, material shrinkage and
cracking, together with the constraint that the component must have manageable size for e.g., ROV
installation or down-hole operation. Water may enter the connector by diffusion through hose and seals, by
leakage through aged or damaged seals, and during the connection cycle of wet mate connectors. Free water
will increase the bulk oil and surface conductivity, leading to local electric field enhancement and eventually
initiate partial discharges and surface tracking discharges.
Another challenge is to verify the influence of the applied voltage frequency on materials and components.
Very long step-outs may require low frequency or even DC voltage transmission. This introduces new
challenges to connector and penetrator design as electric field distribution will be governed by space charge
accumulation and conductivity of the insulation materials involved.
Aims and Goals of This PhD Project and Prospective Design Challenges
The main aim of this project is the development of design criteria for hybrid electrical insulation systems
for use in subsea connectors for oil and gas exploitation at voltage levels higher than 36 kV. On this basis,
the examination of the practical limitations regarding partial discharge inception and long term electric
breakdown strength of interfaces between different insulating components will be of vital importance. For
this purpose, effect of surface pressure, roughness, water content as well as magnitude, type and direction
of the electric stress will be examined. During this PhD project, the experimental and theoretical bases are
expected to be further developed.
To elaborate, for subsea high voltage connectors and penetrators there is a particular attention to mechanical
and electrical design. The electrical design considers the maximum allowable electric field stress of the
insulation materials used. Higher voltage ratings require thicker insulation, improved field grading, and
longer creep distances. However, there is no simple linear relationship between size and voltage when up-
scaling the component. A schematic drawing of a wet-mate connector is shown in Figure 1. The electrical
pin shown in the figure must be long in order to reduce the average electric field stress and avoid electric
creep discharges. The mechanical stress on the pin may be particular high during connections or by external
vibrations, which is a known source of fault condition.
An inherent problem of any cable connector and termination is the presence of interfaces between materials.
If the breakdown strength at a point on the interface is exceeded by local field enhancement, partial
discharges will be initiated. A recent investigation showed that moisture and applied contact pressure play
an important role on the dielectric strength of the interface. Assembling the interface under water, the
breakdown strength of wet interfaces decreased approximately to 50% of the breakdown strength of dry
interfaces.
Water ingress may also initiate severe failure mechanism in wet-mate connectors. By design of special viper
seals as shown in Figure 2 the water ingress during mating can be minimized but never completely
eliminated, which limits the total number of connections. Small amounts of water inside the connector may
be dissolved in the oil until the oil reaches the moisture saturation level. When the moisture saturation level
is reached for a dielectric liquid, either by water ingress or temperature cycling, free water will form in the
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dielectric fluid and on solid/liquid interfaces. Free water will increase the bulk oil and surface conductivity,
leading to local electric field enhancement and eventually initiate PD and surface eroding tracking
discharges.
Fig. 1: Schematic drawing of wet-mate connector receptacle with electrical pin. (1) Metallic housing/ground
potential (2) Polymer insulation (3) Conductor (4) Contact point.
Fig. 2: Principal drawing of a MVAC subsea connector a) before connection and b) after connection. The
function of the diaphragms are to wipe seawater from the male pin during mating.
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Erlend Sandø Kiel
Home Country: Norway
Year of Birth: 1984
Email: [email protected]
Home Page: http://www.ntnu.no/ansatte/erlend.kiel
Master Degree: MSc Globalization
University: NTNU
Graduation Year: 2011
Supervisor: Gerd Hovin Kjølle
Research Group: Electric Power Systems
Co-Supervisor(s): Kjetil Uhlen
Project: HILP - Analysis of extraordinary events in power systems
Methods for understanding and communicating uncertainties and risk
related to extraordinary events
The complexity and uncertainties of the power system are increasing, due to integration of
distributed renewable power generation, the introduction new technologies, more extreme
weather and stronger integration between the Nordic and European power systems.
Extraordinary events are of special interest as they imply substantial consequences to
society. The mechanisms behind these events are not well understood today, and there is a
need to increase the ability to identify, understand and assess extraordinary events.
By building on today's best methods and theories, methods and tools for analysing
extraordinary events in power systems will be developed. The main challenges to be
addressed are the identification of causes and underlying mechanisms, quantification of the
consequences and handling uncertainties.
The project results will provide decision support to make a best possible trade-off between
security of supply and societal costs in planning and operation of the Nordic power system.
The project will build new competence for analysis of extraordinary events, and the
collaboration with transmission system operators and authorities ensures that the
developed methodologies will increase situational awareness as well as aid for deciding on
remedial actions and preparedness plans for the power system. Improved understanding of
the risks associated with extraordinary events will also be of great value for electric utilities,
households and industry in general, as modern society is heavily dependent on a reliable
electric supply.
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Name
Home Country: Norway
Year of Birth: 1989
Email: [email protected]
Home Page: ntnu.edu/employees/martin.kristiansen
Master Degree: Energy and Environmental Engineering
University: NTNU
Graduation Year: 2014
Supervisor: Magnus Korpås
Research Group: Power Systems Group
Co-Supervisor(s): Stein-Erik Fleten and Ove Wolfgang
Project: North Sea Offshore Network
Adequate modelling of Transmission Expansion Planning European power systems are potentially exposed to large-scale integration of renewable
energy sources (RES) in the coming years, due to ambitious decarbonization targets outlined
by the European Commission. The most promising strategy to achieve those goals is harvesting
non-dispatchable solar- and wind production, in combination with flexible, dispatchable
production like hydro. The largest utilization potentials of non-dispatchable resources are
typically located far from the load centers, e.g. offshore wind in the North Sea. The
transmission system operators acknowledge several challenges for the development and
operation of power grids towards these targets, both in terms of security of supply and
efficient market operation. The objective with the PhD project is to identify any challenges
related to transmission expansion planning, and develop adequate decision models for long-
term planning that incorporate both uncertainty and market characteristics for cost recovery.
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Markus Löschenbrand
Home Country: Austria
Year of Birth: 1989
Email: [email protected] [email protected]
Home Page: ---
Master Degree: MSc in Supply Chain Management
University:Vienna University of Business and Economics
Graduation Year: 2015
Supervisor: Magnus Korpås
Research Group: Power Systems
Co-Supervisor(s):Marte Fodstad, Hossein Fahramand
Project: Short Term Multi Market Bidding of Hydro Power
Optimization of Hydro Power Units on multiple Short Term Markets Ongoing integration of continental European system and traditionally and physically less
integrated (island) systems such as Great Britain into the Nordic system adds several
additional factors to be considered. Strong focus has to be put on stability and sustainability
of the system, especially considering that services to reach that goal differ vastly throughout
the different countries. Those ancillary services are the current topic of the ongoing research
in this PhD. The current questions consist of - how do the different services interact; what
potential and risk exists for prospective future services; how do market participants realize
their goals through offering or calling such services?
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The first journal publication (PMAPS2016) dealt with the question on how single
participating units react to specific situations and adjust their behavior in relation to other
participants. Currently an extended model based on this paper is in the works.
The second branch of the research dealt with analysis of offering new ancillary services,
specifically inertial response. A multi market stochastic model was created to analyze the
effect of giving the possibility to cross-trade inertial response on a scheduling algorithm.
Currently, a paper is pending in review.
Future work will be dealing with higher level of multi-market bidding and finding the
interaction between different ancillary service provisions.
Furthermore, a research stay at Tsinghua University in Beijing is being in the works and will
aim to increase the level of depth of the skills and methods of the candidate to solve the
established problem sets.
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Hans Kristian Hygen MeyerHome Country: Norway Year of Birth: 1990 Email: [email protected] Home Page: www.ntnu.edu/employees/hans.meyer
Master Degree: MSc Electric Power Engineering University: NTNU Graduation Year: 2014
Supervisor: Frank Mauseth Research Group: Electric Power Technology Co-supervisor: Atle Pedersen, SINTEF Energy Research Project: “Electrical insulation with low-GWP gases”
Dielectric barriers under lightning impulse stressesEnvironmentally friendly alternatives to SF6-gas for medium voltage switchgear insulation are needed. Increasing size or pressure of the equipment is not economically feasible. One possibility is to use strategically placed dielectric barriers. Previous research has shown that the insulation strength of air gaps can be greatly increased with such methods. More knowledge is, however, needed on the interaction betweenelectrical gas discharges and dielectric surfaces to better understand the underlying mechanisms of the barrier effect. Improved knowledge in this area will be of great importance to increase the accuracy of withstand voltage prediction models for complex geometries.
The main goal of this PhD project is to understand how streamers interact with dielectric barriers under lightning impulse stress. An important aspectis the surface charging of the dielectric. The research involves both experimental work in NTNU’s high voltage lab and computer simulations.
The PhD work is part of a project funded by the Research Council of Norway and the industrial partners ABB AS, Norway and ABB Ltd., Switzerland.
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Razieh Nejati Fard
Home Country: Iran
Year of Birth: 1987
Email: [email protected]
Home Page:
https://www.ntnu.edu/employees/razieh.nejati
Master Degree: MSc in Electric Power Engineering
University: NTNU
Graduation Year: 2013
Supervisor: Prof. Elisabetta Tedeschi
Research Group: Power Systems
Co-Supervisor(s): Prof. Pericle Zanchetta (The University of Nottingham)
Project: Deep-Sea Mining Pilot
Electric Power System Design for Deep-Sea Mining Applications
Deep-sea mining is expected to play an important role for raw material supply in the near
future due to growing demand and less efficient land-based mines. NTNU has established a
deep-sea mining pilot project, involving PhD and postdoc researchers with different expertise
and backgrounds to study various aspects of deep-sea
mining.
The main goal of this project is to design a highly efficient,
stable and reliable electric power system for deep-sea
mining in the Norwegian Sea. Considering the long distance
to shore, an isolated grid with diesel or gas generators
mounted on a ship or a platform with dynamic positioning
capabilities seems to be the best choice. Different
configurations such as on-board or subsea power system,
AC or DC systems are going to be examined. Moreover, all
the necessary power components are going to be studied
well based on their performance, weight, size and
efficiency. High pressure and low temperature at the
seabed in addition to the harsh weather condition at the
surface are also affecting the design criteria. After designing the system, it will be analyzed
thoroughly from systematic point of view including power flow, power quality, short circuit
and stability related issues by doing simulations and possibly lab-scale validation.
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Konstantin Pandakov
Home Country: Russian Federation
Year of Birth: 1989
Email: [email protected]
Home Page:
www.ntnu.edu/employees/konstantin.pandakov
Master Degree: MSc in Electrical Engineering
University: Tampere University of Technology
Graduation Year: 2015
Supervisor: Prof. Hans Kristian Høidalen
Research Group: Power Technology
Co-Supervisor(s): Doc. Jorun Irene Marvik
Project: Power system protection in a smart grid perspective (ProSmart)
Protection of power systems with distributed sources
Embedded or distributed generation (DG) will change the power flow in the system. This has
strong impact on protection of distribution system and such issues as sympathetic tripping,
blinding, miscoordination, and selectivity violation arise. New protective schemes including
directional over-current or distance relays become required, as well as involvement of
communication technologies. Furthermore, network operators are interested in reduction of
incidents of unnecessary DG decoupling, typically caused by voltage and frequency
protection. On the other hand, situations of unintentional islanding must be avoided. It
requires application of adaptive settings, fault location procedures, and fast anti-islanding
protection.
The project consists of modelling and simulation of transients in power system to
study the dynamic impact of distributed sources and relay performance under
various conditions. The project identifies what data must be obtained from DG
units, substations and loads for optimum protection and fault location. The work
also introduces approbation of developed algorithms in laboratory tests. The
research area includes such fields as:
• Distributed sensors
• Communication of syncrophasor data from distributed sources
• Algorithms for fault-location
• Island detection and operation
• Adaptive relaying
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Project Description
Tin Rabuzin
Home Country: Croatia
Year of Birth: 1991
Email: [email protected]
Home Page: http://www.ntnu.edu/employees/tin.rabuzin
Master Degree: Electric Power Engineering, 2015
University: Royal Institute of Technology (KTH)
Supervisor: Prof. Hans Kr. Høidalen
Research Group: Electric Power Technology
Co-Supervisor: Prof. Bruce Mork
Project: ProSmart
System Integration and Performance
It is essential to confirm the functionality of an overall integrated system. The project will investigate
beneficial system information structures and algorithms from centralized to distributed to combined
hierarchical. Algorithms for optimal balance between performance and security will be developed. Data
overload is occurring and the “big data” problem needs solutions.
Instrument transformers, sensors, transducers, and merging units
Data concentrators, protocol converters, and vector processors
Effects of time delays on wide-area performance
Algorithms centralized/distributed/hierarchical
Real-time computing performance (algorithms and data mining)
Correct power system protection and control performance – Security
Optimization of high-speed wide area control calculations
Synchrophasor bad data identification and state estimation
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Iromi Ranaweera
Home Country: Sri Lanka
Year of Birth: 1986
Email: [email protected]
Home page: www.ntnu.edu/employees/iromi.ranaweera
Master Degree: MSc in Renewable Energy
University: University of Agder, Norway
Graduation Year: 2013
Supervisor: Ole-Morten Midtgård
Research Group: Power Technology
Co-Supervisor(s): Kjetil Uhlen
Project: NTNU
Energy storage for control of distributed photovoltaic systems in the
smart grid One of the major goals of the smart grid is, accommodating a large number of distributed
generators in the low voltage (LV) distribution network. PV technology is one of the fastest
growing renewable technology today, not only in large-scale applications, but as small-
distributed generators connected to the LV distribution grid. However, increase in PV
penetration level can cause reverse power flow in the distribution network, resulting over-
voltage problems. This can impose constraint on the installation of PV systems in the
distribution system. Not only that, high PV penetration can overload the transformers,
increase difficulty in voltage control due to bi-directional power flow, and results poor
operating power factor of the transformer. One of the feasible solution to these problems is
use of energy storage. Small-scale energy storage technologies include batteries, super
capacitors, flywheels and hydrogen technology (electrolyzer and fuel cell). However, recently
battery type energy storage has become more popular in residential applications with PV
systems.
This research is aimed at developing effective control methods for grid connected
distributed PV systems using energy storage in the smart grid framework. The focus of the
research is to investigate the solutions for the over-voltage problem using the battery energy
storage units, and optimizing the economics by properly scheduling the battery energy
storage units. Both local scheduling and control methods, and coordinated control methods
for the battery energy storage units with PV systems will be investigated.
30
Ole Christian Spro Home Country: Norway Year of Birth: 1986 Email: [email protected] Home Page: www.ntnu.no/employees/olechrs Master Degree: MSc Electrical Engineering University: NTNU Graduation Year: 2013
Supervisor: Ole-Morten Midtgård Research Group: Energy conversion Co-Supervisor(s): Tore Undeland Project: HiPPE – NTNU
Design of GaN converter for inductive charging applications
Recently, advances have been made in
fabrication of semiconductors based on wide
band gap materials. The most important
materials for future power electronics are silicon
carbide and gallium nitride (GaN). The material
properties of GaN result in devices with superior
characteristics to silicon devices. The material can
resist higher E-fields and has higher electron
mobility. These characteristics result in devices
that has lower on-state losses and that can switch
faster. This gives new opportunities for further
improvement of power electronic converters as
well as new challenges.
One of the applications which could benefit from for GaN based converter systems, is inductive
charging. Inductive charging involves the use of high frequency power electronic converters to transfer
energy between two inductively coupled coils. Using GaN devices could enable operation at higher
frequencies while at the same time increasing the converter efficiency.
The research will focus on the process of developing a GaN based converter system for an inductive
charging application. To successfully establish a converter platform for real applications, several
procedures must be established. Correct measurement of sharp square-shaped high voltage signals
and high frequency currents necessitates high bandwidth probes for correct measurement.
Furthermore, these sharp square-shaped pulses can make it a challenge to comply with
electromagnetic compatibility standards. Thus, design procedures for exploiting the good
characteristics of GaN while handling the challenges will be addressed. The work has started by
developing a full bridge inverter and using it in an existing inductive charging prototype in the
university laboratory.
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32
Abel Assegid Taffese
Home Country: Ethiopia
Year of Birth: 1986
Email: [email protected]
Home Page:
https://www.ntnu.edu/employees/abel.taffese
Master Degree: European Wind Energy Master Program
University: Joint Delft University of Technology and
Norwegian University of Science and Technology
Graduation Year: 2014
Supervisor: Elisabetta Tedeschi
Research Group: Power Systems
Co-Supervisor(s): Erik de Jong (DNV GL/Technische Universiteit Eindhoven)
Modelling and Control of High Voltage DC-DC Converters A hybrid ac/dc grid is foreseen to be the future of the electric power system where the ac and dc grids
complement each other. Since ac grids are relatively well established, substantial research activity has
been geared towards identifying and solving major challenges related to dc grids. Research groups,
such as the Cigré’s Study-Committee B4, have produced a handful of significant results identifying the
challenges and demonstrating the feasibility of dc grids. One such challenge is control of power-flow
in the grid. The Cigré working group B4.58 has been investigating devices and methods to overcome
this challenge. Among the solutions proposed by B4.58 is the use of a dc-dc converter. The dc-dc
converter is also an enabling component in connecting existing point-to-point HVDC installations, such
as those found in the North Sea, which are otherwise incompatible due to difference in operating
voltage, grounding scheme or converter technology. Despite its vital role, research on high voltage dc-
dc converter application is at an early stage.
This PhD research focuses on modelling, control, and analysis of emerging high voltage dc-dc converter
topologies. Existing work on this subject is focused on control and optimization at the component level
with efficiency and size as the main parameters. However, from the power system perspective,
additional aspects, such as power quality and stability, need to be considered as well. This work aims
to develop and validate simplified models of selected candidate topologies to be used in a range of
power system studies. These models will then be used to design controllers that are in-line with system
level requirements.
33
Henning Taxt
Home Country: Norway
Year of Birth: 1983
Email: [email protected]
Home Page:
Master Degree: MSc Electric Power Engineering
University: NTNU
Graduation Year: 2012
Supervisor: Kaveh Niayesh
Research Group: ELA
Co-Supervisor(s): Magne Runde, SINTEF Energy Research
Project: Current interruption in air-filled medium voltage load break switches
Administered by ABB Norway in Skien
Ablation-assisted current interruption in MV switchgear SF6-gas is widely used in medium and high
voltage switchgear today because of its
excellent insulation and current interruption
capabilities. However, due to its high global
warming potential, there is a political pressure
to replace it wherever possible, resulting in a
need for new solutions in the design of
compact low-cost switchgear. A promising
method for current interruption is the
application of gas-emitting insulation
materials, in a process of ablation.
This PhD project is
aimed at studying the
possibility to improve
current interruption
performance by
having certain
polymer materials
exposed to the
switching arc.
The research is based on mainly experimental methods and example of switch geometries
and results are shown in the figures above.
Figure 2 Example of test switch design
Figure 1 Example of measurements, comparing two different switch geometries
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Name: Subhadra Tiwari
Home Country: Nepal
Year of Birth: 1983
Email: [email protected]
Home Page: http://www.ntnu.no/ansatte/tiwari
Master Degree: M.Sc. in Electric Power Engineering
University: Norwegian University of Science and
Technology
Graduation Year: 2011
Supervisor: Prof. Ole-Morten Midtgård
Research Group: ELA
Co-Supervisor(s): Prof. em. Tore Marvin Undeland
Project: HiPPE
Design Principles for Optimal Use of Wide Bandgap Power Semiconductors
The future power electronic system trends are more efficient, more reliable, higher power, lower
weight/volume and higher temperature operation of power electronic converters. Literature studies
show that power semiconductor switches made with wide bandgap material such as SiC and GaN have
potential to fulfill all the aforementioned requirements.
However, the challenges regarding layouts, gate drivers and measurements are encountered which
hinder to fully utilize their potential. Furthermore, higher electrical breakdown field of these materials
helps achieve devices with smaller on-state losses and faster switching speed. However, fast switching
(higher di/dt and dv/dt) combined with small chip size stresses the device with higher di/dt and dv/dt
per chip area, thereby triggering all the parasitic. Higher stray parameters slow down SiC devices, stress
them with higher current and voltage overshoots, larger and longer oscillations and higher losses.
Therefore, it is crucial to reduce stray parameters both in the power and the gate loops to be able to
utilize the fast switching potential of these devices, which is one of the challenges. Thus, a low inductive
busbar design is one of the tasks.
In order to achieve lowest conduction loss at higher current, a higher positive gate voltage is essential
because of lower transconductance of these devices compared to their Si counterparts. Additionally,
they have lower threshold voltage demanding for negative gate voltage during turn-off because higher
dv/dt can couple enough charge to gate through miller capacitance to hit the threshold limit.
Therefore, an optimized gate driver is an issue for these new devices.
Highly accurate and precise measurements are the prerequisites for analyzing the performances of
these devices. For instance, for tracking the fast rising and falling switching waveforms, high bandwidth
probes and oscilloscope are needed. Due to high dv/dt and di/dt, not only the circuit parasitic but also
the probes parasitic influence the measurements. As these devices has very low loss, the accurate loss
measurement is another issue. Thus, developing a reliable methodology and precise and accurate
measurement setup is also one of the focuses of this project.
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Salman Zaferanlouei Home Country: Iran
Year of Birth: 1982
Email: [email protected]
Home Pages: https://scholar.google.no/citations?user=6_vhJ4AAAAAJ&hl=en https://www.ntnu.edu/employees/salman.zaf https://www.researchgate.net/profile/Salman_Zaferanlouei Master Degree: MSc in Energy Engineering
University: Amirkabir University of Technology (Tehran polytechnic)
Graduation Year: 2009
Supervisor: Magnus Korpås
Research Group: Power Systems
Co-Supervisor(s): John Krogstie, Hossein Farahmand
Project: Integration of Electric Vehicles with Smart Grid
Integration of Electric Vehicles with Smart Grid The 21th century electric power grid will be heavily influenced by technology and ICT on all levels of
operation: From physical component installation to automated renewable energy markets, which is
now dubbed the Smart Grid. The possible emergence of revolutionary applications due to this new
technology layer is very high, and one of the most applicable and important entities to utilize the Smart
Grid are plug-in electrical vehicles (PEVs).
Smart grid control can is an example of “Coalition of Independent Agents”. Interaction between agents
could be done either by supervised control or unsupervised one. In the context of smart grid,
supervised and unsupervised control are respectively called centralized and decentralized control. Any
implementation of artificial intelligence in the controller design could enhance the capability of the
agents to decide smartly based on their individual experiences. In this project, we are going to model
an energy-based competition for PEVs over charging their batteries with consideration of grid
constrains an intermittent renewables.
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PhD graduated at Department of Electric Power Engineering, NTNU, from 2000
Year Name Title
2016 Seyed Majid
Hasheminezhad
Tangential electric breakdown strength and PD inception voltage of
Solid-Solid interface
Bjarte Hoff Model predictive control of voltage source converter with LCL filter
Ravindra Babu Ummaneni Design and modelling of a linear permanent magnet actuator with gas
springs for offshore application
Dinh Thuc Duong Online voltage stability monitoring and coordinated secondary voltage
control
Christian Skar Modeling low emission scenarios for the European power sector
Emil Hillberg Perception, prediction and prevention of extraordinary events in the
power system
Traian Nicolae Preda Modelling of active distribution grids for stability analysis
Mehdi Karbalaye Zadeh Stability analysis methods and tools for power-electronics based DC
distribution systems, applicable to on-board electric power systems and
smart microgrids
Nathalie Holtsmark Investigation of the matrix converter application in a DC series-
connected wind farm modulation, control and efficiency
2015 Yonas Tesfay Gebrekiros Analysis of Integrated Balancing Markets in Northern Europe under
Different Market Design Options
Mustafa Valavi Magnetic Forces and Vibration in Wind Power Generators
Nina Sasaki Støa-Aanensen Air Load Break Switch Design Parameters
Gro Klæboe Stochastic Short-term Bidding Optimisation for Hydro Power Producers
Zhaoqiang Zhang Ironless Permanent Magnet Generators for Direct-Driven Offshore Wind
Turbines
Rene Alexander Barrera
Cardenas
Meta-parametrised metamodeling approach for optimal design of power
electronics conversion systems. Application to offshore wind energy
conversion systems
Gilbert Bergna Diaz Modular Multilevel Converter - Control for HVDC Operation
Santiago Sanchez Acevedo Stability Investigation of Power Electronics Systems
A Microgrid Case
2014 Bijan Zahedi Shipboard DC Hybrid Power Systems - Modelling, Efficiency Analysis
and Stability Control
Chuen Ling Toh Communication Network for Internal Monitoring and Control in
Multilevel Power Electronics Converter
Hamed Nademi Advanced Control of Power Converters: Modular Multilevel Converter 37
Håkon Kile Evaluation and Grouping of Power Market Scenarios in Security of Electricity
Supply Analysis
Jonas Sjolte Marine renewable energy conversion: Grid and off-grid modeling, design and
operation
Nadeem Jelani Investigating the Role of Active Loads in the Future Electrical Grid Dominated
by Power Electronics
Erik Jonsson Load Current Interruption in Air for Medium Voltage Ratings
2013 Sverre Skalleberg Gjerde Analysis and Control of a Modular Series Connected Converter for a
Transformerless Offshore Wind Turbine
Vrana, Til Kristian System Design and Balancing Control of the North Sea Super Grid
Larsen, Pål Johannes Energy Savings in Road Lighting
Correct Lighting at all times and every condition
Aigner, Tobias System Impacts from Large Scale Wind Power
Nguyen, Dung van Experimental studies for streamer phenomena in log oil gaps
Jafar, Muhammad Transformer-Less Series Compensation of Line-Commutated Converters for
Integration of Offshore Wind Power
Torres Olguin, Raymundo Grid Integration of Offshore Wind Farms using Hybrid HVDC Transmission
Control and Operational Characteristics
Wei, Yingkang Propagation of Electromagnetic Signal along a Metal Well in an
Inhomogeneous Medium
2012 Yordanov, Georgi Hristov Characterization and Analysis of Photovoltaic Modules and the Solar
Resource Based on In-Situ Measurements in Southern Norway
Haileselassie, Temesgen
Mulugeta
Control, Dynamics and Operation of Multi-terminal VSC-HVDC Transmission
Systems
Abuishmais, Ibrahim SiC Power Diodes and Juction Feild-Effect Transistors
Zhang, Shujun Percussive Drilling Application of Translation Motion Permanent
Magnet Machine
Ruiz, Alejandro Garces Design, Operation and Control of Series-connected Power Converters
for Offshore Wind Parks
Jaehnert, Stefan Integration of Regulating Power Markets in Northern Europe Offshore
Wind
Tesfahunegn, Samson G. Fuel Cell Assisted Photo Voltaic Power Systems
Farahmand, Hossein Integrated Power System Balancing in Northern Europe
Models and Case Studies
Suul, Jon Are Control of Grid Integrated Voltage Source Converters under Unbalanced
Conditions – Development of an On-line Frequency-adaptive Virtual
Flux-based Approach
2011 Marvik, Jorun Irene Fault localization in medium voltage distribution networks with distri-
buted generation
38
Krøvel, Øystein Design of Large Permanent Magnetized Synchronous
Electric Machines – Low Speed, High Torque Machines – Generator for
Direct Driven Wind Turbine –Motor
for Rim Driven Thruster
Chen, Anyuan Investigation of PM machines for downwhole applications
2010 Chiesa, Nicola Power Transformer Modeling for Inrush Current Calculation
Danielsen, Steinar Electric Traction Power System Stability
Low-frequency interaction between advanced rail vehicles and a rotary
frequency converter
Nordgård, Dag Eirik Risk Analysis for Decision Suppurt in Electricity Distribution System
Asset Management
Greiner, Christopher
Johan
Sizing and Operation of Wind-Hydrogen Energy Systems
2009 Eek, Jarle Power System Integration and Control of Variable Speed Wind
Turbines
Kulka, Arkadiusz Sensorless Digital Control of Grid Connected Three Phase Converters for
Renewable sources
Guidi, Giuseppe Energy Management Systems on Board of Electric Vehicles, Based on
Power Electronics
2008 Pedersen, Per Atle Forces Acting on Water Droplets in Electrically Energized Oil Emul- sions;
Observations and Modelling of Droplet Movement Leading to
Electrocoalenscence
Østrem, Trond Reliable Electric Power Conversion for Connecting Renewables to the
Distribution Network
Skjellnes, Tore Digital Control of Grid Connected Converters for Distributed Power
Generation
Næss, Bjarne Idsøe Operation of Wind Turbines with Doubly Fed Induction Generators
During and After Line Voltage Distortions
Belsnes, Michael Martin Optimal Utilization of the Norwegian Hydropower System
Helseth, Arild Modelling Reliability of Supply and Infrastructural Dependency in
Energy Distribution systems
2007 Di Marzio, Giuseppe Secure Operation of Regional Electricity Grids in Presence of Wind
Power Generation
Gullvik, William Modeling, Analysis and Control of Active Front End (AFE) Converter
Andreassen, Pål Digital Control of a Zero Voltage Switching Inverter for distributed
Generation of Electrical Energy
Hoff, Erik
Stjernholm
Status and Trends in Variable Speed Wind Generation Topologies
Løken, Espen Multi-Criteria Planning of Local Energy Systems with Multiple Energy
Carriers
Ericson, Torgeir Short-term electricity demant response
Mauseth, Frank Charge accumulation in rod-plane air gap with covered rod
2006 Maribu, Karl
Magnus
Modeling the Economics and Market Adoption of
Distributed Power Generation
Catrinu, Maria Decision-Aid for Planning Local Energy Systems. Application of Multi-Criteria Decision Analysis 39
2005 Hellesø, Svein Magne Dynamic analysis and monitoring of power transmission cables using
fibre optic sensors
Lund, Richard Multilevel Power Electronic Converters for Electrical Motor Drives
Bjerkan, Eilert High Frequency Modeling of Power Transformers -
Stresses and Diagnostics
Vogstad, Klaus-Ole A system dynamics analysis of the Nordic electricity Market: The tran-
sition from fossil fuelled toward a renewable supply within a liberalised
electricity market
2004 Øvrebø, Sigurd Sensorless control of Pemanent Magnet Synchronous Machines
Kristiansen, Tarjei Risk Management in Electricity Markets Emphasizing Transmission
Congestion
Korpås, Magnus Distributed Energy Systems with Wind Power and Energy Storage
2003
Botterud, Audun Long Term Planning in Restructured Power Systems: Dynamic Model-
ling of Investments in New Power Generation under Uncertainty
Ettestøl, Ingunn
Analysis and modelling of the dynamics of aggregate energy demand
2002 Kolstad, Helge Control of an Adjustable Speed Hydro Utilizing Field Programmable
Devices
Norheim, Ian Suggested Methods for Preventing Core Saturation Instability in
HVDC Transmission Systems
Warland, Leif A Voltage Instability Predictor using Local Area Measurements. VIP++
Ruppert, Christopher Thermal Fatigue in Stationary Aluminium Contacts
2001 Larsen, Tellef Juell Daily Scheduling of Thermal Power Production in a Deregulated Elec-
tricity Market
Kleveland, Frode Optimum Utilization of Power Semiconductors in High-power High-
frequency Resonant Converters for Induction Heating
Myhre, Jørgen Chr. Electrical Power Supply to Offshore Oil Installations by High Voltage
Direct Current Transmission
2000 Oldervoll, Frøydis Electrical and thermal ageing of extruded low density polyethylene
insulation under HVDC conditions
Doorman, Gerard Peaking capacity in Restructured Power Systems
Hystad, Jan Transverse Flux Generators in Direct-driven Wind Energy converters
Pleym, Anngjerd EMC in Railway Systems. Coupling from Catenary System to Nearby
Buried Metallic Structures.
40