department of electric power engineering ntnu may 2016

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

http://www.ntnu.no/elkraft

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


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


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


Home Page:

http://www.ntnu.edu/employees/fahim.abid

Master Degree: Electrical Engineering

University: KTH Royal Institute of Technology


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


Home Page:

Master Degree: MSc (Engg)

University: Indian Institute of Science,

Bangalore


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


Year of Birth: 1992


Home Page: www.ntnu.no/ansatte/espen.bodal

Master Degree: Energy and Environmental Engineering

University: NTNU


Supervisor: Magnus Korpås


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

http://www.ntnu.no/ansatte/espen.bodal

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


Home Page:

http://www.ntnu.edu/employees/atousa.elahidoost

Master Degree: Electric Power Engineering

University: NTNU


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.

7

Name: Atsede Gualu Endegnanew

Home Country: Ethiopia

Year of Birth: 1986


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


Supervisor: Kjetil Uhlen


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

mailto:[email protected]

http://www.ntnu.no/ansatte/atsede.g.endegnanew

Erlend L. Engevik


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


Supervisor: Arne Nysveen


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


mailto:/[email protected]

http://www.researchgate.net/profile/Erlend_Engevik

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


Year of Birth: 1990


Master Degree: Electric power engineering

University: NTNU



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.

12

Martin Håberg


Year of Birth: 1991


Home Page: ntnu.edu/employees/martin.haberg

Master Degree: Energy and Environmental

Engineering

University: NTNU


Supervisor: Gerard Doorman


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.

14

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


Home Page: http://www.ntnu.edu/employees/sigurd.h.jakobsen

Master Degree: MSc Electrical engineering

University: NTNU


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


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


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

19

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

20

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.

21

Erlend Sandø Kiel


Year of Birth: 1984


Home Page: http://www.ntnu.no/ansatte/erlend.kiel

Master Degree: MSc Globalization

University: NTNU


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.

22


http://www.ntnu.no/ansatte/erlend.kiel

Name


Year of Birth: 1989


Home Page: ntnu.edu/employees/martin.kristiansen

Master Degree: Energy and Environmental Engineering

University: NTNU



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.

23

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




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?

24


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.

25

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.

26

Razieh Nejati Fard

Home Country: Iran

Year of Birth: 1987


Home Page:

https://www.ntnu.edu/employees/razieh.nejati

Master Degree: MSc in Electric Power Engineering

University: NTNU


Supervisor: Prof. Elisabetta Tedeschi


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.

27


https://www.ntnu.edu/employees/razieh.nejati

Konstantin Pandakov

Home Country: Russian Federation

Year of Birth: 1989


Home Page:

www.ntnu.edu/employees/konstantin.pandakov

Master Degree: MSc in Electrical Engineering

University: Tampere University of Technology


Supervisor: Prof. Hans Kristian Høidalen


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

28


https://www.ntnu.edu/employees/konstantin.pandakov

Project Description

Tin Rabuzin

Home Country: Croatia

Year of Birth: 1991


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


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

29


Iromi Ranaweera

Home Country: Sri Lanka

Year of Birth: 1986


Home page: www.ntnu.edu/employees/iromi.ranaweera

Master Degree: MSc in Renewable Energy

University: University of Agder, Norway


Supervisor: Ole-Morten Midtgård


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


http://www.ntnu.edu/employees/iromi.ranaweera

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.

31

Abel Assegid Taffese

Home Country: Ethiopia

Year of Birth: 1986


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


Supervisor: Elisabetta Tedeschi


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


Year of Birth: 1983


Home Page:

Master Degree: MSc Electric Power Engineering

University: NTNU


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

34

Name: Subhadra Tiwari

Home Country: Nepal

Year of Birth: 1983


Home Page: http://www.ntnu.no/ansatte/tiwari

Master Degree: M.Sc. in Electric Power Engineering

University: Norwegian University of Science and

Technology


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.

35


http://www.ntnu.no/ansatte/tiwari

Salman Zaferanlouei Home Country: Iran

Year of Birth: 1982


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)




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.

36


https://scholar.google.no/citations?user=6_vhJ4AAAAAJ&hl=en

https://www.ntnu.edu/employees/salman.zaf

https://www.researchgate.net/profile/Salman_Zaferanlouei

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.

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department of electric power engineering ntnu may 2016

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