Blar i Øvrige samlinger på forfatter "Uhlen, Kjetil"
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Mode Shape Estimation using Complex Principal Component Analysis and k-Means Clustering
Haugdal, Hallvar; Uhlen, Kjetil (Chapter, 2019)We propose an empirical method for identifying low damped modes and corresponding mode shapes using frequency measurements from a Wide Area Monitoring System. The method consists of two main steps: Firstly, Complex Principal ... -
Non-intrusive identification of hydro power plants' dynamics using control system measurements
Jakobsen, Sigurd Hofsmo; Bombois, Xavier; Uhlen, Kjetil (Peer reviewed; Journal article, 2020)In this paper we propose two non-intrusive methods for identifying hydro power plant dynamics using standard system identification techniques. The purpose of the tests is to obtain transfer functions relevant for the ... -
Operation and Control of hybrid AC/DC transmission grids
Uhlen, Kjetil; Endegnanew, Atsede Gualu; Haileselassie, Temesgen Mulugeta (Chapter, 2019)This paper describes challenges and possibilities related to operation and control of hybrid AC/DC power transmission grids. The aim is to discuss topics that transmission system operators and regulators must assess in ... -
Optimal control of variable speed hydropower - Utilising model predictive control and virtual inertia for delivering power system services
Reigstad, Tor Inge (HydroCen brief;Nr. 3, Report, 2021) -
Optimal Operation of Battery Storage for a Subscribed Capacity-Based Power Tariff Prosumer—A Norwegian Case Study
Berglund, Frida; Zaferanlouei, Salman; Korpås, Magnus; Uhlen, Kjetil (Journal article; Peer reviewed, 2019)The cost of peak power for end-users subject to a demand charge may be substantial, expecting to increase further with the vast growth of power-demanding devices. In cases where load-shifting is not a viable option for ... -
Optimized Control of Variable Speed Hydropower for Provision of Fast Frequency Reserves
Reigstad, Tor Inge; Uhlen, Kjetil (Peer reviewed; Journal article, 2020)This paper deals with the design of controllers for variable speed hydropower (VSHP) plants with the objective of optimize the plants performance. The control objectives imply enabling fast responses to frequency deviations ... -
Performance evaluation of the empirical method for online detection of power oscillations: a multiterminal HVDC application
Sanchez Acevedo, Santiago; Duong, Dinh Thuc; Taffese, Abel Assegid; Uhlen, Kjetil; Tedeschi, Elisabetta (Chapter, 2018)This paper presents the performance evaluation of an empirical method for online detection of power and voltage oscillations electric grids and is used as a monitoring system to evaluate the grid performance. Additionally, ... -
Post-processing algorithmfor damped and step-change events detection in PMU signals
Negi, Sanjay Singh; Kishor, Nand; Uhlen, Kjetil; Negi, Richa (Chapter, 2017)The study presents an algorithm using signal processing techniques to screen PMUs data for events. The algorithm can be applied on multiple PMUs data for possible events detection and their display. The algorithm analyze ... -
Power Oscillation Monitoring using Statistical Learning Methods
Haugdal, Hallvar; Uhlen, Kjetil (Chapter, 2019)This paper describes development and testing of a method for estimation of electromechanic modes and corresponding mode shapes from frequency or voltage angle measurements in Wide Area Monitioring Systems. The method uses ... -
Resultatrapport NFR Project no 246784: Operation of the Smart Grid With Wide Area Information
Uhlen, Kjetil (Research report, 2019) -
Scenario selection in composite reliability assessment of deregulated power systems
Kile, Håkon; Uhlen, Kjetil; Kjølle, Gerd Hovin (Journal article; Peer reviewed, 2014)Power market analysis should be incorporated in reliability assessments of deregulated power systems. For the Nordic power system, this is done by using The Multi-area Power-market Simulator (EMPS) for long-term power ... -
Signal processing for time-frequency representation of synchro-phasor data
Negi, Sanjay Singh; Kishor, Nand; Kumar, Avinash; Uhlen, Kjetil (Journal article; Peer reviewed, 2017)With increased number of phasor measurement units (PMUs) deployment in the power system, there is growing interest in real-time event detection. The study in this paper presents post-processing approach to map the event ... -
Smooth Transition Between Controllers for Floating Wind Turbines
Lindeberg, Eivind; Svendsen, Harald Georg; Uhlen, Kjetil (Journal article; Peer reviewed, 2012)This paper presents a novel wind turbine control system which gives a smooth power output during transitions between different controllers. The paper presents an implementation of a control system designed for an offshore ... -
Stability Assessment of Power Systems Based on a Robust Sum-of-Squares Optimization Approach
Kalemba, Lester; Uhlen, Kjetil; Hovd, Morten (Chapter, 2018)Secure operation of the evolving power systems, characterised by more renewable energy sources and increasingly variable consumption, will require enhanced monitoring and more automatic control actions. One example is the ... -
Stability properties of nonlinear model predictive control of variable speed hydropower
Reigstad, Tor Inge; Uhlen, Kjetil (Peer reviewed; Journal article, 2020)This study presents a method for small-signal analysis of an advanced, multi-variable control system for variable speed hydropower (VSHP) plants. A model predictive controller (MPC) optimises the power plant performance. ... -
Testing of a hydro power plant’s stability and performance using PMU and control system data in closed loop
Jakobsen, Sigurd Hofsmo; Uhlen, Kjetil (Journal article; Peer reviewed, 2019)In response to recent concerns regarding deteriorating frequency quality in the Nordic power system, the Nordic transmission system operators (TSOs) have developed draft requirements for the provision of frequency containment ... -
Time-varying coherency study using TFC
Shweta, NN; Kishor, Nand; Uhlen, Kjetil; Mohanty, S. (Chapter, 2017)An assessment of the dynamic interactions between generators will provide valuable information which could improve control action and hence maintain stability in the interconnected system. The paper presents the study on ... -
Transmission Loss Minimization Using Artificial Intelligent Algorithm for Nordic44 Network Model based on Hourly Load Variation
Monshizadeh, Shohreh; Uhlen, Kjetil; Hegglid, Gunne.J (Peer reviewed; Journal article, 2020)Optimal power flow is a nonlinear optimization method to enhance the performance and flexibility of a power system. This paper explores the use of particle swarm optimization (PSO) algorithm as an artificial intelligence ... -
Using Decentralized Control Techniques for Interaction Analysis in Hybrid AC/DC Grids
Endegnanew, Atsede Gualu; Kalemba, Lester; Uhlen, Kjetil (Chapter, 2018)One of the ancillary services that can be provided by Multi-terminal Direct Current (MTDC) grid to connected ac grids is power oscillation damping (POD). However, using PODs at multiple terminals of an MTDC grid results ... -
Variable Speed Hydropower Conversion and Control
Reigstad, Tor Inge; Uhlen, Kjetil (Peer reviewed; Journal article, 2020)The objective of this paper is to develop and analyse a variable speed hydropower (VSHP) model that can aid the design of controllers that maximize the utilization of power plant for the provision of ancillary services, ...