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281 Uppsatser om Transient stability - Sida 1 av 19
Uljabuouda vindkraftpark turbinmodellering och stabilitetsanalys
This master thesis has been performed at Solvina in Gothenburg for Skellefteå Kraftand Vattenfall Eldistribution. The aim of it is to investigate the consequences of theinstallation of a wind power plant on the mountain Uljabuouda in the vicinity ofArjeplog. Especially the impacts on voltage and Transient stability are examined.Furthermore, the amount of extra strain on the voltage regulation equipment and theneeds for increased regulation capabilities are looked into.The wind power plant is planned to be built by Skellefteå Kraft and connected to a130 kV grid owned by Vattenfall Eldistribution. The work comprehends the followingmain parts:- Theoretical studies aimed at wind turbines and power system stability issues.- Modelling of the type of wind turbines assumed to be built on Uljabuouda.- Simulations of different operation cases and analysis of the simulation results.The results from the simulations show that, as far as voltage stability and extraworkload on tap-changers are concerned, the wind power plant does not, in anysignificant manner, worsen the present conditions. The problem of overloading theline between Arvidsjaur and Vargfors is also minor.
Agroinfiltration och transient uttryck av CRISPR/Cas9 : en förberedande studie på Nicotiana benthamiana och potatis (Solanum tuberosum L.)
Den senast utvecklade tekniken för riktade förändringar av genom in-vivo är baserad på CRISPR/Cas-systemet för vilket förutsättningarna i Nicotiana benthamiana och potatis,
Solanum tuberosum, här undersöktes. För att föra in genkonstruktioner i växterna användes Agrobacterium tumefaciens som via vakuum kommer i kontakt med de inre delarna av bladen varefter de gener som finns på en binär vektor uttrycks transient. Först undersöktes de
optimala parametrarna för erhållandet av ett högt transient uttryck med hjälp av ett grönt fluorescerande protein, GFP. Dessa parametrar användes sedan för att infiltrera en
CRISPR/Cas-konstruktion som designats för att introducera mutationer genom att klyva ett exon i genen för granulbundet stärkelsesyntas, GBSS. Det visade sig under första delen av arbetet att det ej gick att erhålla transient uttryck i potatis med denna metod.
Krafter på rörsystem vid transient flöde : En jämförelse mellan RELAP5 och Fluent
At Forsmarks Kraftgrupp AB (FKA) forces on pipe systems due to transient flow are frequently calculated as a step to verify their structural integrity. In nuclear industries these forces are often calculated with a one dimensional thermal-hydraulic analysis-code called RELAP5. When calculations regarding more complex geometries are needed, the three dimensional code Fluent is often used. This code is highly time consuming and requires large computational power.This projects aim is to compare calculations of pressure, flow and forces carried out by RELAP5 and Fluent for an arbitrary pipe section during transient flow conditions. This has been accomplished by constructing a simple geometry for which a transient flow is simulated in both programs.
Åsktransienter och överspänningar : En spänningsfylld simulering av elkraftsystemet vid Forsmark 3
A power system will inevitably be subjected to transient overvoltages, most often produced by switching operations and lightning strikes. These transient overvoltages may harm sensitive equipment without sufficient protection, but it is not an easy task to predict what transients may occur or how they affect the system. A fault occurred in a low voltage system at Forsmark 2012 and overvoltages from lightning were concluded as the probable cause. The three aims with this thesis are to develop and test a model of the power system at Forsmark 3, analyse the transient behaviour of the system when subjected to lightning surges and identify critical parameters, and lastly to provide a tool for investigating the protection of the system. The modelling and simulations were performed in the freely available simulation program LT Spice.
PERMADEATH MEDPERMANENTA OCHTRANSIENTA MÅL : Effekten permanenta och transienta mål har påpermadeath.
Arbetet ämnar undersöka vilken effekt på spelupplevelsen ett transient kontra permanent mål har i ett spel med permadeath, samt hur spelaren reagerar på mekaniken när spelets förutsättningar förändras. Arbetet utgår ifrån hypotesen att ett spel som presenteras med ett transient mål är mer passande för permadeath och gör döden mer acceptabelt för spelaren. Arbetet går först igenom en introduktion av permadeath som spelmekanik, vad förlust i spelsammanhang innebär, samt de två mål-variationerna, följt av arbetets frågeställning och hur denna ska utmätas. För detta arbete har ett spel med permdeath skapats i två variationer, en presenterad med ett permanent mål och en med ett transient mål. Testen utfördes sedan genom två grupper, vars spelupplevelse mättes genom en enkätundersökning.
På uppdrag av Allah - En studie av legitimiteten i den saudiarabiska statsapparaten
Since 2003 Saudi Arabia is under attack from domestic Al Qaida-cells which, by random shootings of westerners and bombings of compounds and official state buildings, is trying to challenge the stability of the royal regime. According to Al Qaida, the Royal family is attacked because of their friendly relations to the US and for not implementing Islam in the Saudi society as profound as they ought to. Political analyst finds it obvious that the Islamic Al Qaida-cells by terrorism is trying to erode the stability in the kingdom.An important foundation for stability for any government is legitimacy. The aim of this thesis is to examine the royal legitimacy strategy in the state bureaucracy of Saudi Arabia. The question at issue is: how has the royal family constructed the civil, military and religious bureaucracies to maintain and promote stability and legitimacy?The thesis focuses on the on three different units within these three bureaucracies and it surveys the way they are staffed and organized to strengthen and maintain legitimacy for the royal family.
Stabilitetsberäkningar och åtgärdsförslag vid islast på Skålandammen
Hydropower is an important source of energy in Sweden and accounts for about 46 % of the total energy production. Sweden has about 1 200 hydropower plants and with the intention of raising the pressure head of the water and to store water, dams are built by the power plants. The storage reservoirs make it possible to adjust the energy production by demand and season. Dams in connection to the reservoirs are subjected to additional loading during periods of high floods or when an icecap in the winter is formed on the reservoirs. In order to maintain the dam safety, the power companies in Sweden are working with guidelines for dam safety from RIDAS.
Kommersiella Fastighetshyror och Finansiell Stabilitet
In recent years, global organizations safeguarding financial stability has started to track commercial property markets. One of the reasons for this refers to the fact that commercial property constitutes a large share of bank lending. Simultaneously, bank exposures to commercial property are extensive and risky since collateral values are strongly correlated to borrowers cash flows. Since banks are viewed to play a key role for financial stability, studying the relationship is well motivated. To better understand how commercial property markets interact with financial stability, this paper develops an econometric model for studying the commercial rental market.
Mätning av Emissioner från en Diesel Motor under Transient Driftförhållande
Transient driftförhållande blir allt mer intressant för forskare och tillverkare och de största svårigheterna är att minska emissionerna utan att påverka bränsleförbrukningen eller motorns respons vid gaspådrag negativt. Huvudmålet med det här examensarbetet var utvärdera olika metoder för att mäta NOx och antal partiklar med hög tidsupplösning för att möjliggöra studier av emissioner under transient driftförhållande.I arbetet har en Horiba MEXA 120NOx NOx-sensor studerats med avseende på linearitet, mätsäkerhet och responstid. Försök för att öka noggrannheten har också gjorts genom att kompensera för varierande skalfaktor för utsignalen och för responstiden.Ett spädsytem har arbetats fram för att ge hög tidsupplösning och god repeterbarhet. I detta ingick en Rotating Disc spädare och en två-stegs Dekati spädare. Spädsystemet var kopplat till en TSI Ultrafine Condensation Particle Counter 3025 A (CPC) och var nödvändigt för att hålla koncentrationen inom det mätbara området.
Kalibrering av en transient GT-Power modell av en SI PFI turbo motor
I detta arbete behandlas transient simulering i ett 1D-simuleringsprogram, i dettafall Gamma technologies GT-Power. Vad som behöver ändras i en modell för attden skall kunna simulera en motor under transienta driftsfall med godnoggrannhet har undersökts. När detta är gjort, skall det undersökas hur väl dentransient kalibrerade modellen kan simulera en motor med förändrad rörgeometripå insugs- eller avgassidan, och vad som måste omkalibreras om detta inte ärfallet.Den viktigaste slutsatsen av detta arbete är vikten av att ha en korrekt framtagenkompressormapp i modellen. Den som fanns tillgänglig under arbetet hade baramätdata ned till 70000 rpm. Detta resulterade i en överskattning av massflödet iden lägre regionen i den av GT-Power framställda kompressormappen.
Dammsäkerhetsanalys via stabilitetsberäkningar för Långströmmens kraftverk : En jämförelse mellan olika dimensioneringsmetoder
A detailed dam safety evaluation (in Sweden called FDU) was performed in 2009 by WSP where stability control was performed for Långströmmen power plant with associated spillways. This evaluation concluded that stability could not be ensured, and risk of sliding occurred. The evaluation is based entirely on the recommendations outlined in RIDAS, the power companies guidelines for dam safety, and it is clear that extensive renovations are necessary to stabilize the dam.In this work, the stability will also be checked with guidance through new proposals on guidelines for concrete dams sliding stability, ELFORSK?s report 08:59. This report considered the guidelines in RIDAS as oversimplified, both from an international perspective, but also with regard to the current state of knowledge regarding dam safety.
STABILITET I INSOMNI, ÅNGEST, DEPRESSION OCH UTBRÄNDHET OCH RELATIONERNA TILLSTÅNDEN EMELLAN
Mental illness is today the leading cause of long-term sick leave and insomnia, anxiety, depression and burnout are among the most common conditions. The aim of the study was to investigate the stability of these conditions and how this is influenced by gender and age, as well as the extent to which these states are risk factors for each other. The participants were a random sample (n = 2336) from the general population in the age of 18-79 years. The results showed that stable illness was more common among women than men, and that stable illness decreased with aging. The stability itself was not affected by gender or age. Relations between the conditions were bidirectional and they constitute major risk factors for each other (odds ratios, OK = 2.37 to 6.46). The largest risk factor for a condition is, however, previous occurrence of the same problem. Previous burnout was found to be a significantly larger risk factor for future burnout than previous insomnia for future insomnia (OK = 9.63 and 5.74, respectively). The results suggest that insomnia, anxiety, depression and burnout, despite their differences, are similar regarding symptoms and underlying causes. The importance of early interventions to prevent comorbid conditions which are more complicated and more difficult to treat is emphasized..
Reliabilitetstest på balanstesterna Unilateral stance och Limits of stability
Människans balanssinne är ett av våra viktigaste sinnen som dagligen sätts på stora prov då vi som tvåbenta individer ska upprätthålla kroppen i normal position vid rörelser och aktiviteter. Människans balans bygger på tre olika sensoriska system som arbetar i synergi för att upprätthålla kroppen i en bra position. Balance Master är ett mätinstrument för att mäta människans posturala kontroll. Syfte: Studiens syfte var att undersöka reliabiliteten i balanstesterna Unilateral stance och Limits of stability utförda på en Neurocom balance master över bestämd tid på friska individer. Material/metod: 11 friska försökspersoner mellan 23 och 29 år utförde balanstesterna Limits of stability och Unilateral stance vid fyra olika testtillfällen.
Yeast in forage crops and silage aerobic stability at 15 Swedish dairy farms
This study investigates the role of yeast in green crop and its impact on the aerobic stability of silage. Fresh crop was collected from 15 farms in southern and middle parts of Sweden during the summer 2014; samples from the primary harvest was collected from eight farms and samples from the first regrowth harvest was collected from seven farms. The grass was ensiled in 1.7 l glass silos. After three months of ensiling, silos were opened and silages were stored aerobically for 10 days. Samples from both harvests were ensiled in completely airtight silos, but samples from the second harvest were also ensiled in slightly ventilated silos.
Chemical analyses and yeast counts were performed for fresh crop and silage.
Dynamisk modellering av kärnreaktor
The purpose of this thesis has been to develop a tool for modelling and simulating the nuclear plant Ringhals 3. The model should be used to improve the knowledge on the dynamics of the plant. Ringhals 3 is being upgraded to produce more power and a tool for analyzing the new operating conditions is needed.The work in this thesis has consisted of improving and developing an existing model of Ringhals 3 made with the modelling tool Dymola. The model has been validated by comparing the results of a simulated house load transient with data from the actual plant. Validation shows good agreement with data from the real plant.