This project was done in cooperation with the TE-EPC-LPC section at CERN. They were experiencing failures in one of their power converter from the rectifying power diodes, and were interested in finding the reason for the failure. They were observing a high leakage current in some of the diodes. The purpose of this project was therefor to investigate the reliability of a diode, and its different failure mechanisms. Diodes can fail from multiple mechanisms some of which can be detected under operation of the diode, in this project the possibility of predicting the lifetime of the diode from its reverse leakage current was investigated. CERN suspected that the failure was either due to avalanche currents in the device or because thermal cycling in the device. Therefor was a non-repetitive avalanche current test, repetitive avalanche current test and a power cycling test performed on the diode. The non- repetitive avalanche current test gave no failures, proving that single event avalanches were not the reason for failure. In the repetitive avalanche current test the diodes was crashed, but no connection between leakage current and time before failure could be observed. In the power cycle test it was observed that failure was induced much faster in a diode with a much higher reverse leakage current than another.

On the way to meet the internationally sanctioned climate targets, zero emission buildings / zero energy buildings (ZEB) will be an important step. Research is ongoing on what a reasonable definition of ZEB will contain. In Norway, it is decided that the building code should be nearly zero energy buildings from the year 2020. In this master’s thesis, an optimization model for finding cost-optimal investment and operational strategies for ZEB is developed. The building modelled, is a passive school with a hydronic heat distribution system. Possible investments include photovoltaic solar cells (PV), solar collectors, heat pumps, biomass boilers, electric boiler, heat storage and connection to the district heating grid. The model is designed as a dynamic mixed integer programming model, and implemented in Mosel Xpress. The model minimizes the total discounted costs of operations and investments over the lifetime of the building. Different restrictions of zero CO2 emissions, zero primary energy consumption and level of grid burden can be applied. The analysis shows that if a zero CO2 restriction with Norwegian CO2 factors are applied, the least expensive way to reach ZEB is by investing in PV in combination with pellet biomass boiler as base load and district heating to cover peak demand. To reach the zero balance for the school with Norwegian CO2 factors, the highest hourly value for export of electricity per hour exceeds the maximum hourly value of imports by about 120%. If European factors for CO2 is applied, it will be more reasonable to reach ZEB than with Norwegian factors. If asymmetric primary energy factors are used instead of symmetric factors, investment in PV becomes higher, and the peak export values increases. The model is developed as a deterministic model, and does not take into account uncertainties in input data. To compensate for this, various sensitivity analyses are conducted. Future work includes testing the model with load profiles for other types of buildings.

This master thesis studies the possible pathways to support military vehicles and ground troops with electrical power a more efficient way, than the present solution. Present energy solution is based on generation of electrical power from internal combustion engines and/or stored energy in batteries. The usage of the vehicles engine for generation of electricity in static positions, results in several disadvantages on a modern battlefield. The batteries specific energy increase every year, but the soldier’s energy need has increased even faster, resulting in a problematic weight load for the dismounted soldier. In the thesis several new or improved solutions are investigated. The solutions are based on technology available today or within the next decade (2020) and selected on the basis of military criteria. A flexible model has been made in an energy simulating program capable to simulate a number of different energy configurations based on future electrical power consumption. Modelling and simulation of the soldiers power system has been recommended by earlier studies [10], but similar models have not been found by the author. The simulation results reveal that improvements of soldiers’ energy solution are feasible. By implementing new or better batteries in the current energy system, considerable improvement can be achieved. Introduction of fuel cells based on methanol fuel starts to become mature, and can result in several advantages on the battlefield. Solar harvesting can give an additional energy supply, but depend highly on insolation and available time for harvesting.

The objectives of this master thesis have been to model and simulate oxy-combustion CO2 capture in a cement plant. The model developed is a process simulation of the calcination process with varying degree of air in-leakage, where heat is supplied by combustion in an oxygen rich environment, followed by capture of the CO2. The further gas separation after H2O condensation to achieve the required CO2 quality was evaluated. In addition to the process simulations, a review of literature related to oxy-combustion CO2 capture and cement production was performed, and an engineering evaluation of the necessary modifications to the cement plant conducted.A simulation model was built in Aspen HYSYS, and student Jelmer de Winter’s project work was utilized as a starting point. The model was developed with the aim to achieve results comparable to a process model constructed by the European Cement Research Academy (ECRA) in 2009. The goal was to capture as much of the CO2 as possible, and to achieve a CO2 purity of minimum 95 mol-% after the CO2 Compression and Purification Unit (CPU).CO2 purity in the dry flue gas of ~85 mol % was achieved, with a CO2 capture rate up to 96.4 %. Five different air in-leakages (2, 4, 6, 8 and 10 % of total flue gas flow) were tested. The results showed that the CO2 concentration in the flue gas decreased with increasing degree of air in-leakage. The decrease in CO2 concentration causes an increase of the power consumption of the CO2 CPU of ~2.6 % per percentage point of air in-leakage, and the CO2 capture rate was also reduced when the air in-leakage increased. These results agree well with results from previous oxy-combustion studies, and show the importance of minimizing air in-leakages in the cement plant.If oxy-combustion capture is to be utilized at a cement plant, some process modifications and additional equipment is required. An Air Separation Unit (ASU) is needed to provide almost pure oxygen for the combustion process. A Compression and Purification Unit (CPU) is also required, in order achieve the necessary CO2 purity and transport conditions. When using oxy-combustion technology, both the material conversion in the cement kiln system and the operational specifications of the overall process are different from those in conventional kiln operation. However, research made by ECRA in 2012 showed that the negative impacts of oxy-combustion on the product quality seem to be negligible.Other necessary process modifications when retrofitting with oxy-combustion are news design of the kiln burner and the clinker cooler in the cement plant. In addition, prevention of excessive air in-leakage by improving sealing locations at the cement plant is necessary, as the simulation results show. This is possible e.g. by waste gas flushed systems, or by an improved maintenance of inspection doors and similar devices. The CPU is up to a certain point capable of handling changes in the flue gas composition at short-term inspections; however it limits its efficiency.

The operational properties of a bipolar configuration composed of a Line-Commutated Converter (LCC) and a Voltage Source Converter (VSC) in a multilevel topology (MMC) are investigated. Simulation models are made in the PSCAD software in order to represent the two bipolar HVDC-links between Norway and Denmark, named Skagerrak 3 and Skagerrak 4. The topology combines two fundamentally different converter technologies with an intricate switching scheme for the function of power reversal.The objective of this thesis is to validate the three simulation models; a monopolar LCC model, a monopolar Modular Multilevel Converter (MMC) model, and an LCC-MMC model in a bipolar configuration. By investigating the interaction of the combined LCC model and MMC model, a better understanding of the challenges of the bipolar link is achieved. The steady state behaviors of the three systems are as expected based on the theory. The LCC consumes reactive power, and require reactive power compensation and filtering. When combined with the MMC, the MMC is able to provide the reactive power consumption by the system. There is an interaction between the MMC and the passive filters of the LCC, resulting in the need to redesign the filters in the bipolar configuration. Also, the DC voltages in the combined model are found to be divided somewhat unevenly between the HVDC-links.When a three-phase to ground fault is applied to the inverter side of the models, the LCC suffer from failure of commutation. This is due to the reduction in the AC voltage, and is to be expected. A DC chopper is placed at the MMC DC-link and reduces the DC voltage overshoot significantly during the fault. When the LCC and MMC systems are combined, they operate in an independent manner, and as a result, no additional protection arrangements are necessary.A single-phase to ground fault at the inverter side of the models, gives rise to harmonic disturbances due to the unbalance of the fault. The reduction in AC voltage results in failure of commutation at the LCC inverter side. The LCC and MMC systems are still almost unaffected by each other during the fault, and so no additional protection systems are required for the combined model.Finally, a DC pole to ground fault is applied to the three simulation models. The LCC model does not recover from the fault, because of loss of controllability in the PI controllers. There are solutions for this problem, for example anti-windup PI controller. An interesting result is observed when the two models are combined into the bipolar configuration. The MMC is able to support the LCC in such a way that it recovers. DC breakers are required for high voltage and current spikes during the DC fault at the MMC link. The LCC and MMC systems are no longer operating independently, and different protection strategies must be implemented when compared to the monopolar models.

Det nye Sparebankkvartalet i Trondheim ble tatt i bruk høsten 2010 og er satt opp av Sparebank 1 SMN (Sparebank Midt-Norge). I tillegg til å ha et energisparende bygg, var målet å oppnå meget godt inneklima i lokalene for å fremme trivsel og helse blant de ansatte. HR-avdeling har hatt løpende kontakt med brukerne av bygget for å registrere hvordan opplevelsen i nytt bygg har vært. Mange av brukerne er fornøyde med de nye omgivelsene, men en del har problemer med at temperaturen er for lav, som arbeidsdagen negativt. NTNU har i samarbeid med Sparebank 1 SMN foretatt beregninger og bekreftet at løsningen med eksponert betong, datagulv og fortrengningsventilasjon var mer energieffektiv enn en konvensjonell ventilasjonsløsning i himling med omrøring. Denne masteroppgaven dokumenterer inneklimaet og kartlegger hvordor brukerne synes det er for kjølig, i tillegg til at et uttrykk for den termiske massens påvirkning av lufttemperaturen er funnet. Mye av arbeidet ligger i valg av måleparameter, måleutstyr,samt finne ut hvilke parameter som er representative for evaluering av inneklimaet. Måleparametrene som ble valgt ut som representative for inneklima, var operativ temperatur, lufthastighet, lufttemperatur, luftmenge og CO2-nivå.På grunn av manglende måleutstyr ble det ikke gjennomført målinger av den operative temperaturen. Det ble heller ikke gjennomført målinger av luftmengden. Det ble besluttet å bruke verdier på luftmengden fra sentral driftskontroll(SD)-anlegget ved evaluering av inneklimaet.Første måling bidro til etablering av et uttrykk for den termiske massens påvirkning på lufttemperaturen pr. meter. Termoelementer ble benyttetfor å måle overflatetemperaturen til betongen i plenumet, samtidig som lufttemperaturen inn og ut av plenumet ble registrert med utstyr fra TinyTag. Differansen mellom temperaturen inn i plenumet og temperturen ut av plenumet ble estimert til 3,5°C, og temperaturøkningen på tilluften i plenumet pr. meter ble estimert til 0,22 °C /m. Den store temperaturdifferansen kan føre til variasjoner av tilluftstemperaturen over kontorlandskapet.En sammenligning av CO2-nivået fra SD-anlegget ble gjort med resultat fra målinger gjennomført med en datalogger fra Kimo, tatt i arbeidssone E3. Deretter ble plassering av givere i landskapet undersøkt, for å se om de var representative for CO2-konsentrasjonen i kontorlandskapene. Plasseringen viste seg å være tilfredstillende og giverne er ikke i veien for brukerne. De måler rett verdi på CO2-konsentrasjonen i rommet, og de får med seg variasjonene i løpet av dagen. Evalueringen av inneklimaet ble basert på lufttemperaturen istedetfor den operative temperaturen, hvor det ble antatt at overflatetemperaturene i landskapet var normale.Gjennomsnittsverdien på lufttemperaturen i kontorlandskapet er innenfor akseptabelt område, 21-23,5°C, i løpet av dagen. Resultater fra spørreundersøkelsen viser at brukerne er mer fornøyde med temperaturen etter lunsj, men det er likevel et ønske om økt temperatur i lokalet gjennom hele dagen. Mindre nattkjøling av den termiske massen, kan gi en høyere tilluftstemperatur til kontoret på begynnelsen av dagen og dermed imøtekomme ønsket om en høyere tempertur i landskapet.Den maksimale lufthastigheten målt under første måling under et skrivebord i landskapet, var til tider helt oppe i 0,25 m/s i høyden 0,6 m. Det maksimalt forventede antall misfornøyde på 14,25 %, ved målinger i høyden 0,6 m over gulvet under et skrivebord. Turbulensintensiteten var ikke målt, men ble satt til 40 %. For en fullverdig konklusjon burde man måle strålingen fra overflater i landskapene, for å se om det er noe mer enn trekk som kan resultere i at brukerne synes at det er kaldt. Noen av ventilene er plassert relativt nærtbrukerne, og en ny plassering av ventilene bør vurderes. Kommentarer om trekk fra avvtrekksventilen ovenfra og ned på brukerne har ikke blitt undersøkt nærmere, men dette kan være en faktor som øker ubehaget hos brukerne. Luftmengden er innenfor tillatt grense gitt av tek10, det samme gjelder CO2-konsentrasjonen, som holder seg under 900 ppm.

EU har planer for en storstilt utbygging av uregulerbar kraft, og etterspør regulerbar kraft som kan balansere forskjellen mellom kraftforbruk og kraftproduksjon. Norge har et fleksibelt vannkraftsystem, og kan bli en leverandør av balansekraft ved å bygge ut store pumpekraftverk. Urevatn og Vatndalsvatn i Setesdalen i Sør- Norge har potensiale for utbygging av pumpekraftverk. Det er særlig vannmagasinenes store vannvolum, korte innbyrdes avstand og høydeforskjellen mellom dem som gjør de interessante for en pumpekraftutbygging. Formålet med denne oppgaven er å skissere en mulig utforming av et pumpekraftverk mellom Urevatn og Vatndalsvatn. Hovedfokuset i oppgaven er tunnelsystemet og at pumpekraftverket som helhet skal representere kombinasjonen av optimal økonomi og gode tekniske løsninger. Det er gjort en rekke tekniske og markedsmessige vurderinger for å kunne optimalisere de nødvendige elementene av pumpekraftverket. Den installerte effekten er dimensjonert ved å analysere variasjonen i dansk vindkraftproduksjon over en 10- års periode. Den optimale installerte effekten er beregnet til å være 1600 MW slik at kraftverket får en pumpeevne på 549 m3/s. Ved design av vannveien er det i hovedsak benyttet beregningsmetoder av overslagsmessig karakter. Vannveien er 2630 meter lang og er designet med skrå tilløpstunnel og horisontal avløpstunnel. Det optimale tunneltverrsnittet er funnet til å være 360 m2. Aggregatet må dykkes 44 meter i forhold til undervannet for å unngå kavitasjon. De totale kostnadene for bygging av det designede pumpekraftverket er beregnet til å være 3762 MNOK. På bakgrunn av enkle kriterier for stabilitet av det dynamiske systemet, er det funnet av det er behov for et svingesystem. Et luftputekammer er derfor valgt for å bedre stabiliteten. Likevel er det konkludert med at det må gjøres frekvensanalyser av det dynamiske systemet for å kunne avgjøre behovet for et svingesystem. Det er konkludert med at et pumpekraftverk mellom Urevatn og Vatndalsvatn er meget godt egnet for å kunne levere balansekraft til Europa, der store mengder effekt kan bygges ut til en relativt lav kostnad.

SummaryRock Bolts, improved design and possibilitiesMaster thesis NTNU 2012Student : Capucine Thomas-LepineSupervisor : Leif LiaKey words : rock foundation, small concrete dam, rock mass classification, rock joints, shear strength of rock discontinuities, fully grouted passive rock bolts designMasters Thesis : “Rock bolts, improved design and possibilities” is a continuation from the Masters Thesis NTNU 2011 “Rock bolts in dams, expected capacity” by Lars Kristian Neby. Internationally, dam engineering focuses mainly on pre-stressed anchors in rehabilitation and improvement of stability of large dams, which is undergoing constant research in North America. Passive rock bolts are used in small concrete dam foundations to ensure sufficient stability against overturning moment from ice loads. This concerns the majority of dams in Norway, over 98% of whose electricity comes from hydropower developed over the last 100 years and still developing. Design is ruled by regulation from NVE (Norwegian water resources and energy directorate) published first in the 1980s, and regularly revised until the retroactive “Retningslinjer for betongdammer” in 2005. This design method for passive rock bolts is conservative with regards to rock capacity, as it is worldwide. The model, developed in the early age of rock bolt development in 1977 by Littlejohn and Bruce, considers the rock resistance as equivalent to the weight of the cone of rock around the bolt. Rock engineering has improved since, often with regards to underground engineering, which is not necessarily transposable to dam engineering. The inherent uncertainty in rock mass characterization slowed development of new design method for passive rock bolts. This is however of great interest in the Norwegian hydropower industry, and for applications to other civil engineering structural foundations. This thesis is meant to develop knowledge of qualitative and quantitative rock mechanisms in passive rock bolts in order to improve their design.The work is composed of three parts, as follows :A study on rock mass capacity and mechanisms in dam foundations, comes first. An empirical and quantitative estimation of rock mass strength with regards to recognized classification Q, RMR or GSI is proposed, based on Wyllie (1992) and results from Lars K. Neby. Full scale tests are then performed to the assess validity of empirical relationships developed in the first part between rock mass quality and rock bolt capacity (maximal tension load in pull out tests). 50 steel bolts with diameter 25mm and mortar grouted length 0.4m were pulled out with logging of strength and deformation in a rock quarry presenting various degrees of rock quality (RMR 40 to 80), representative of expected conditions for dam foundations. Rock quality was assessed for each bolt by laboratory testing (intact material properties) and rock mass characterization on site supplemented by core drilling or video inside hammer drilled holes. This program of tests was an improvement on the protocol developed and performed by Lars K. Neby on 18 bolts, whose results give the first relevant clues on parameters such as limit range of quality of rock (RMR>40), length of bolt (0.4m), maximal capacity (more than 20 tons, when conservative calculations assessed 0.2 tons). The results of testing confirm the relationships developed in a more statistical approach.Conclusions from these two parts lead to a proposition for a new design model, with a higher resistance contribution from the rock. The three modes of failure (rock, steel, grouting) are considered for ensuring resistance of a maximal stress of 180MPa (to avoid important deformations in the structure). Factors of safety and the range of validity in the rock mass condition for the proposed design are also considered. The thesis concludes with propositions for further works in order to :- Further extend the domain of validity of the proposed design.- Review methods of control of installed passive rock bolts.- Document and improve knowledge of load transfer mechanisms in passive rock bolts in dams.

Bakgrunnen for oppgaven er et ønske om å redusere lekkasjetapet på vannledningsnettet i Narvik by. Reduksjon av lekkasjetapet kan gjøres ved utskiftning/rehabilitering av ledninger, lokalisering og reparasjon av lekkasjer og trykkreduksjon.Målet med prosjektet er å gi et grunnlag for videre arbeid med reduksjon av lekkasjer, ved hjelp av fin-lokalisering, trykkreduksjon og generell planlegging av hvilke ledningsstrekk som skal saneres i de kommende år.I rapporten gjennomgås vannbalanse for lekkasjesonene på ledningsnettet i Narvik, lekkasjetap med ulike indikatorer presenteres og lekkasjesonene rangeres. Det utredes muligheter for reduksjon av lekkasjetapet ved å redusere trykket der det er praktisk gjennomførbart. Videre sammenlignes lekkasjetapet i Narvik med andre kommuner og forslag til organisering av lekkasjesøk fremstilles.Utarbeidelsen av vannbalansen er gjort på grunnlag av foreliggende data om målt forbruk på kommunalt ledningsnett, innrapporterte målerverdier fra større abonnenter og folkeregisterdata. Det er i enkelte tilfeller manglende data fra målere på ledningsnettet som har måttet blitt erstattet av erfaringsdata som gir visse muligheter for feil. Resultatene viser et totalt vanntap på ca. 55 % for Narvik. Etter sonebalanse er satt opp og lekkasjesonene rangert er sone 7, 12, 10 og 4 rangert som verst. Disse tre sonene står for ca. halvparten av det totale lekkasjetapet. Resultatene fra simuleringene ved en trykkreduksjon i sone 12 gir en lekkasjereduksjon på ca. 13 % i denne sonen. Ut fra erfaringer fra andre kommuner og størrelsen på forsyningsområdet i Narvik anbefales det å benytte ca. et halvt årsverk til lekkasjelytting.

The thesis studied resilience in drilling and well operations at an oil company operating on the Norwegian continental shelf, with a major focus on the onshore drilling support function in the case company. Drilling for oil and gas involves significant risks, according to scientists, authorities and the industry itself. The risks of offshore oil extraction have also been manifested through major accidents like the Deepwater Horizon. At the same time, the industry faces challenges like less reservoirs and rising operating costs. The development of new technology for collecting and transmitting data and new ways of working emerged about a decade ago and is often referred to as Integrated Operations or simply IO. The changes made new ways of working over distance possible, which were said to have produced numerous advantages that would lead to improved productivity and profitability as well as HSE. Some scientists however have warned against possible negative risks associated to Integrated Operations that should be accounted for. At the same time, within the safety management science Resilience Engineering has evolved as a well acknowledged theory for building resilient organizations. However, the literature on Resilience Engineering is rather new, and some authors have called for more empirical studies of resilience in practice. To perform a study on resilience in practice in an IO environment, the following research questions were formulated:•How does collaboration technology and integrating of operations influence resilience?•How can resilience be engineered in an IO environment?A case study design was chosen, and the case was delimited to compass the selected case company's drilling and well operations units with the organization's onshore drilling support center as the core object of study. The qualitative research methods semi structured interviews of key personnel at the case company and observation of work practice were used for data collection. In addition some documents were used.The study started off by investigating how the case operates, and in particular how they utilize collaboration technology and work over geographical and organizational borders. Specifically, the focus of attention was to identify the risks and challenges in drilling and well operations and how the organization operates in such an environment. The data collection then focused on how the organization manages risks and what factors contribute to resilience. Relevant literature was reviewed in order to identify characteristics resilient organizations. The data collected at the case company were then compared with the literature study and the organization's resilience was then sought to explain.The analysis resulted in a set of recommendations that was seen as key contributors to resilience for the case, and may be useful recommendations for organizations in other relevant contexts. The suggested steps towards a resilient organization are:•Organize the workers into teams of experts in collaborative open space offices•Make sure employees have experience from relevant work practice•Have organizational processes that facilitate collaboration in place•Use analytics on historical and realtime data extensively•Have knowledge databases with lessons learned and best practices•Invest in new technology and workplace facilities•Create positive attitudes towards change•Encourage curiosity and employees' interest in their field of expertise