| 1. |
- Bekele, Yared, et al.
(författare)
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Sustainable Off-grid Systems with Integration of Renewable Generation and Hydrogen-Fuel Cell
- 2022
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Ingår i: IEEE PES Innovative Smart Grid Technologies Conference Europe. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper has investigated the role of renewable hydrogen produced from excess variable renewable energy (VRE) in reducing carbon emission and excess electricity curtailment in off-grid systems. The excess electricity produced from VRE is used for production of green hydrogen by electrolysis of water through Electrolyser in addition to serving deferrable load and battery storage systems (BSS). The hydrogen Produced from VRE sources is supplied to fuel cells to give electricity. The case study is based on modeling and simulation of off-grid systems with photovoltaics (PV) and wind turbines (WT) as two possible sources of power and, BSS and hydrogen as two possible storage media for an unelectrified small rural town called Gara Botora-Kemisie in Ethiopia. A Comparative analysis of the system with diesel generator (DG) and the system without DG is performed to identify a sustainable system for the selected site. Different case studies have been performed for comparison purposes. The results of the simulation show that, the system with PV, WT, BSS and hydrogen fuel cell is more sustainable and fossil free system and viable in reducing renewable energy curtailment.
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| 2. |
- Beyene, Yared Bekele, et al.
(författare)
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On the design and optimization of distributed energy resources for sustainable grid-integrated microgrid in Ethiopia
- 2023
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 48:78, s. 30282-30298
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a study that focuses on alleviating the impacts of grid outages in Ethiopia. To deal with grid outages, most industrial customers utilize backup diesel generators (DG) which are environmentally unfriendly and economically not viable. Grid integration of hybrid renewable energy systems (HRES) might be a possible solution to enhance grid reliability and reduce environmental and economic impacts of utilizing DG. In this study, an optimization of grid integrated HRES is carried out for different dispatch and control strategies. The optimal power supply option is determined by performing comparative analysis of the different configurations of grid integrated HRES. The result of the study shows that grid integrated HRES consisting of photovoltaic and wind turbine as renewable energy sources, and battery and hydrogen as hybrid energy storage systems is found to be the optimal system to supply the load demand. From the hydrogen produced on-site, the FC generator and FCEVs consume 143 620 kg/yr of hydrogen which is equivalent to 394 955 kg/yr gasoline fuel consumption. This corresponds to saving 1 184 865 kg/yr of CO2 emissions and 605 703 $/yr revenue. Besides, this system yields 547 035.4 $/yr revenue by injecting excess electricity to the grid. The study clearly shows the economic and environmental viability of this new technology for implementation.& COPY; 2023 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).
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| 3. |
- Beyene, Yared Bekele, et al.
(författare)
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On Virtual Complex Impedance Droop Control of VSC-Based Islanded Microgrids
- 2023
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Ingår i: Proceedings of 2023 IEEE PES Innovative Smart Grid Technologies Europe, ISGT EUROPE 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the droop control techniques used to ascertain the proper sharing of active and reactive power of multiple VSCs in an islanded microgrid. The dynamic model of the system control loops is performed in a dq rotating reference frame. The droop control loop is analyzed, taking into account the inductive nature of the output impedance of the microgrid due to the inductor of the filter and coupling inductor. To minimize the circulating current that flows between parallel VSC, a virtual complex impedance loop is included in the proposed controller. In order to avoid the stability problem occurring at the resonant frequency of the LCL filter, a parallel resistor is added to the LCL filter capacitor. For both equal and proportional power-sharing strategies, the proposed controller can achieve accurate power-sharing with an excellent dynamic performance of the system. The simulation results are presented to reveal the accurate performance of the proposed controller.
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| 4. |
- Borenius, Seppo, et al.
(författare)
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Expert-Guided Security Risk Assessment of Evolving Power Grids
- 2022
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 15:9, s. 3237-
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Tidskriftsartikel (refereegranskat)abstract
- Electric power grids, which form an essential part of the critical infrastructure, are evolving into highly distributed, dynamic networks in order to address the climate change. This fundamental transition relies on extensive automation solutions based on communications and information technologies. Thus, it also gives rise to new attack points for malicious actors and consequently, increases the vulnerability of the electric energy system. This study presents a qualitative assessment of power grid cybersecurity through expert interviews across countries in Europe and the U.S. to gain understanding of the latest developments and trends in the cybersecurity of future electric energy systems. The horizon of the assessment is 10 years spanning until the early 2030s. Thereafter, the study identifies how and to which extent the risks identified to be most significant are understood and addressed in the latest research and industry publications aiming at identifying areas deserving specific further attention. The most significant threats based on the assessment are False Data Injection (FDI), Denial of Service (DoS) supply chain, and ransomware and malware attacks.
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| 5. |
- Dogra, Arundhati, et al.
(författare)
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Potential Impact of Electric Vehicles Connected to the Grid-A Pre-Study for the Swedish Power System
- 2023
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Ingår i: Proceedings of 2023 IEEE PES Innovative Smart Grid Technologies Europe, ISGT EUROPE 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- In the year 2022 Sweden registered close to 5 million vehicles. According to the Power Circle report of 2021, the growth rate that year for the usage of Electric vehicles (EVs) was a steady 82 percent. Sweden is on the brink of an energy crisis, the electricity demand is increasing by the day, and expanding the generation portfolio is a challenging task both logistically and from the perspective of the swiftness with which this energy crisis should be handled. This paper tries to analyze the potential of this Vehicle to Grid(V2G) technology by creating an analytical scenario to quantify the amount of energy that can be injected into the grid if all the power generation is shut down and the country has to survive on the power pushed back by the EVs into the grid assuming that reactive power compensation is present to maintain the stability of the grid. The paper presents analytical calculations on the number of hours the current EV fleet can help sustain the grid in case of a blackout. The results obtained can be utilized for the modeling of emergency plans in grid operation in case of a partial failure.
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| 6. |
- Du, M., et al.
(författare)
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A som based anomaly detection method for wind turbines health management through scada data
- 2016
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Ingår i: International Journal of Prognostics and Health Management. - : Prognostics and Health Management Society. - 2153-2648. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a data driven method for Wind Turbine system level anomaly detection and root sub-component identification is proposed. Supervisory control and data acquisition system (SCADA) data of WT is adopted and several parameters are selected based on physical knowledge in this domain and correlation coefficient analysis to build a normal behavior model. This model which is based on Self-organizing map (SOM) projects higher-dimensional SCADA data into a two-dimension-map. Afterwards, the Euclidean distance based indicator for system level anomalies is defined and a filter is created to screen out suspicious data points based on quantile function. Moreover, a failure data pattern based criterion is created for anomaly detection from system level. In order to track which sub-component should be responsible for an anomaly, a contribution proportion (CP) index is proposed. The method is tested with a two-month SCADA dataset with the measurement interval as 20 seconds. Results demonstrate capability and efficiency of the proposed method.
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| 7. |
- Gopalakrishnan, Pavithra, et al.
(författare)
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Peak Demand Shaving Based on Solar and Load Forecasting at Port of Gavle
- 2022
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Ingår i: 2022 17th International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2022. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Solar energy is considered as one of the most promising solutions to prevent climate change, and optimal utilization of solar energy contributes to reducing dependence on non-renewable energy sources. Distributed generation can help support the delivery of clean and reliable power to consumers. In this paper, an Energy Management System (EMS) is developed along with load and Photovoltaic (PV) generation forecasting to perform peak shaving of electricity demand. The results from the proposed method are implemented in a real case study, in Port of Gavle in Sweden. Total revenue generated from services of peak-shaving and frequency regulation is maximum in the scenario considering high PV generation and high consumption on a selected experimental day in July. The results show that PV-battery storage systems are effective options to increase the integration of renewable energies in the grid, flatten the load, and achieve stabilized operation.
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| 8. |
- Holmgren, Emil, et al.
(författare)
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More Electric Aircraft (MEA) : Scaling Aspects and Weight Impact
- 2022
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Ingår i: ICAS, Proceedings, 33th Congress of the International Council of the Aeronautical Sciences, Stockholm, Sweden. - : International Council of the Aeronautical Sciences.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper is about investigating the differences in fuel consumption of conventional and equivalent electricalsubsystems of passenger aircraft. The goal is to develop a framework that can help evaluate fuel consumptionof passenger aircraft, both conventional aircraft and More Electric Aircraft (MEA), for a given size of aircraftand a given stretch of flight.The work presented in this paper originates from pre-studies within MEA research performed by the ReliabilityCentered Asset Management (RCAM) research group at KTH in collaboration with SAAB that has been doneon a passenger aircraft with comparable size to the Airbus A320. The main difference to the prior study isthe addition of subsystem weight, passenger scaling effects, environmental dependencies and flight profile, alladded to increase the accuracy and diversity of the model. The fuel consumption is based on studies of existingtechnology for several passenger aircraft from Airbus and Boeing. The main focus was the EnvironmentalControl System (ECS).A numerical model of passenger aircraft including the ECS was constructed in MATLAB with different levelsof electrification, a conventional ECS or a fully electric ECS. A special case with an Airbus A320 with 180passengers doing a round trip between Copenhagen and Stockholm on a hot day was studied.The results show possible fuel savings in the magnitude of 4% to 8% when electrifying the ECS for the casestudied and for aircraft with 156 to 700 passengers.
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| 9. |
- Mazidi, Peyman
(författare)
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From Condition Monitoring to Maintenance Management in Electric Power System Generation with focus on Wind Turbines
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With increase in the number of sensors installed on sub-assemblies of industrial components, the amount of data collected is rapidly increasing. These data hold information in the areas of operation of the system and evolution of health condition of the components. Therefore, extracting the knowledge from the data can bring about significant improvements in the aforementioned areas.This dissertation provides a path for achieving such an objective. It starts by analyzing the data at the sub-assembly level of the components and creates four frameworks for analysis of operation and maintenance (O&M) for past, present and future horizons at the component level. These frameworks allow improvement in operation, maintenance planning, cost reduction, efficiency and performance of the industrial components. Next, the dissertation evaluates whether such models can be linked with system level analysis and how providing such a link could provide additional improvements for system operators. Finally, preventive maintenance (PM) in generation maintenance scheduling (GMS) in electric power systems is reviewed and updated with recent advancements such as connection to the electricity market and detailed implementation of health condition indicators into the maintenance models. In particular, maintenance scheduling through game theory in deregulated power system, for offshore wind farm (OWF) and an islanded microgrid (MG) are investigated.The results demonstrate improvements in reducing cost and increasing profit for the market agents and system operators as well as asset owners. Moreover, the models also deliver an insight on how direct integration of the collected operation data through the developed component level models can assist in improving the operation and management of maintenance for the system.
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| 10. |
- Noland, Jonas Kristiansen, et al.
(författare)
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The Race to Realize Small Modular Reactors : Rapid Deployment of Clean Dispatchable Energy Sources
- 2024
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Ingår i: IEEE Power and Energy Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 1540-7977 .- 1558-4216. ; 22:3, s. 90-103
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Tidskriftsartikel (refereegranskat)abstract
- Small modular reactors (SMRs) are currently touted as the next evolution of nuclear energy. They are a type of nuclear reactor designed to be smaller in size than a traditional reactor. Nevertheless, they are based on the same fission technology that splits atoms to create heat, which can then be used to generate electricity. SMRs can offer clean, reliable power and heat at manageable costs for both on- and off-grid communities. Currently, there are more than 100 proposed SMR reactor designs worldwide participating in the race to commercialization. This article presents a comprehensive review of the different SMR technologies that are currently being developed. The technical characteristics of the SMRs have been evaluated to provide insights into their complementary role in a renewable energy system and highlight how they can accelerate the journey toward a deeply decarbonized world.
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