Blar i NTNU Open på forfatter "Uhlen, Kjetil"
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A Scheme for Creating an Small-Signal On-line Dynamic Security Assessment Tool - Using PSS/E and PacDyn
Bjørsvik, Knut (Master thesis, 2016)The trend in today's electrical power system is that consumption and power peaks are increasing, which will push the grid to its limits. The large deployment of new renewable energy connected to the grid has also shifted ... -
A Slim Wind Turbine Concept with Low Frequency AC Connection
Hole, Andreas Nyhagen (Master thesis, 2016)This thesis aims to investigate the feasibility of using a slim wind turbine concept together with a low frequency alternating current (LFAC) transmission system in an offshore wind farm system. By a slim wind turbine ... -
A Topology-based Scheme for Adaptive Underfrequency Load Shedding
Duong, Dinh Thuc; Uhlen, Kjetil (Chapter, 2017)This paper presents a topology-based scheme for adaptive underfrequency load shedding (UFLS). By tracking changes of power system topology and information about power flow, the proposed method is able to identify islanded ... -
A Wide Area Load Shedding Scheme to Prevent Voltage Instability
Solås, Jon Erik (Master thesis, 2016)These days, power systems are operated close to their stability limit, and disturbances such as transmission line contingencies can cause the system to lose stability. If the system loses stability, countermeasures has to ... -
Active Control of Reactive Power in a Modern Electrical Rail Vehicle
Toreid, Eivind (Master thesis, 2011)Modern electrical rail vehicles employ four-quadrant voltage source converters, which allow independent control of real and reactive power. This thesis focuses the control of reactive power at the vehicle regarding load ... -
Aggregation of Power grid Models
Amare, Mulugeta Hadis (Master thesis, 2017)In recent days, energy demands are growing rapidly. To meet this demand rise, several distributed energy sources and power generations are adding to the existing power system network. At the same time, cross-country and ... -
Analysis of frequency stability: How wind power and HVDC connections affect the future power system
Hellebust, Håkon (Master thesis, 2018)Many modern power systems are facing massive changes. Two of the main development trends are more interconnections between neighboring power systems and significant growth in installed capacity of wind power and other ... -
Analysis of IEEE Power System Stabilizer Models
Hammer, Anders (Master thesis, 2011)Student: Anders HammerSupervisor: Kjetil UhlenContact: Daniel MotaCollaboration with: Voith HydroProblem descriptionIEEE (Institute of Electrical and Electronics Engineers) presented in 2005 a new PSS structure named ... -
Analysis of Slow Frequency Variations in the Nordic Power System
Oftebro, Anja (Master thesis, 2014)Slow oscillations in system frequency, with a periodic time of 60-90 seconds and amplitude of 50 mHz, has been observed in the Nordic grid. As a result the frequency is outside the limit of 50 +/- 0,1 Hz more often. It is ... -
Analysis of the Slow Floating in Grid Frequency of the Nordic Power System: Impact of Hydraulic System Characteristics
Grøtterud, Magnus (Master thesis, 2012)This Master's Thesis work deals with the analysis of the observed slow floating in the grid frequency of the Nordic power system. Measurements indicate that the frequency of this floating or oscillation is around 11-17 ... -
Area Based Secondary Frequency Control in the Nordic Power System
Andersen, Katrine Gabrielsen (Master thesis, 2016)In order for a power system to function properly, it is necessary that the power production is equal to the power demand at all times. The next day's power balance is scheduled by the transmission system operators (TSO's) ... -
Avoiding AC/DC grid interaction in MMC based MTDC Systems
Endegnanew, Atsede Gualu; Bergna-Diaz, Gilbert; Uhlen, Kjetil (Chapter, 2017)In this paper, the interaction between ac and dc grids is studied for two types of MMC control structures; conventional and non-conventional control structures. Linear analysis methods that are based mode shapes and ... -
Case Study of Integrating an Offshore Wind Farm with Offshore Oil and Gas Platforms and with an Onshore Electrical Grid
He, Wei; Uhlen, Kjetil; Hadiya, Maheshkumar; Shi, Gang; del Rio, Emilio (Journal article; Peer reviewed, 2013)This research project explored the technical feasibility of utilizing an offshore wind farm as a supplementary power source to several electrical grids of offshore oil and gas platforms and providing surplus power to an ... -
Case study of offshore wind farm integration to offshore oil and gas platforms as an isolated system - System Topologies, Steady State and Dynamic Aspects
Hadiya, Maheshkumar (Master thesis, 2011)The objective of this thesis work has been to investigate the electric system stability, reliability and power security of an off-grid isolated network system integration of an offshore wind farm to offshore oil and gas ... -
Closest security boundary for improving oscillation damping through generation redispatch using eigenvalue sensitivities
Parreiras, TJMA; Gomes, S; Taranto, Glauco Nery; Uhlen, Kjetil (Journal article; Peer reviewed, 2018)This paper proposes an algorithm for determining a minimum generation redispatch capable of moving specific oscillation modes to the closest small-signal security boundary that guarantees them a desired damping factor. The ... -
Control Challenges and Possibilities for Offshore Wind Farms
Anaya-Lara, Olimpo; Tande, John Olav Giæver; Uhlen, Kjetil; Adaramola, Muyiwa S. (SINTEF Energi. Rapport;, Research report, 2013)Electricity generation from large offshore wind farms is being gradually accepted as a feasible solution to meet the rapid increase in energy demands. However, although the technology is progressing fast, a major drawback ... -
Control of VSC During Unsymmetrical AC Faults in Offshore Wind Farms
Kirkeby, Henrik (Master thesis, 2013)This master thesis has analyzed the eects of unbalanced faults in the ACgrid of an oshore wind farm. The wind farm is connected to shore with aVoltage Source Converter (VSC) HVDC link, and the wind turbine genera-tors ... -
Coordinated Control of Multiple HVDC links using backstepping
Ersdal, Anne Mai; Imsland, Lars Struen; Uhlen, Kjetil (Journal article, 2012)This article regards a power system containing multiple High Voltage Direct Current (HVDC) links. The topic is to exploit the HVDC lines’ ability to control the power supplied by them to increase the stability of the system. ... -
Detecting instant of multiple faults on the transmission line and its types using time-frequency analysis
Na, Shweta; Kishor, Nand; Uhlen, Kjetil; Mohanty, Soumya R (Journal article; Peer reviewed, 2019)In a complex interconnected network, due to dynamic interaction between the AC networks, at the time of multiple occurrences of faults, the successful relay operation is threatened. For security and reliability of power ... -
Development of a test system for identification of turbine dynamics using the dc power flow
Jakobsen, Sigurd Hofsmo; Uhlen, Kjetil (Journal article; Peer reviewed, 2018)Recent concerns about the frequency quality in the Nordic power system has lead to increased research on hydro turbine governors. Among this research is the use of system identification methods. However, there has been no ...