| 1. |
- Cui, Yue
(författare)
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A Fault Detection Framework Using Recurrent Neural Networks for Condition Monitoring of Wind Turbines
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The global energy system is experiencing a transition to a sustainable system with ambitious targets for increased use of renewable energy. One key trend for this transition has been the large introduction of wind power and integration into the electricity grid. In order to succeed in this transition, there is a need to develop efficient tools to support the handling of the assets. Asset management is a coordinated activity for the organization to get value from an asset. As the main part of asset management, maintenance includes all the technical and corresponding administrative actions to keep or restore the asset to the desired state in which it can perform its required functions. Traditional maintenance is usually based on scheduled monitoring and physical inspections. However, with new access to data and information about condition-based maintenance shows to be an efficient solution for asset management. This thesis explores data-driven solutions for electrical equipment to generate alerts towards potential operation risks, which targets digital, efficient, and cost-effective asset management. Specifically, the thesis investigates wind turbines.This thesis proposes a fault detection framework for cost-effective preventive maintenance of wind turbines by using condition monitoring systems. The thesis utilizes the data from supervisory control and data acquisition systems as the main input. For log events, each event is mapped to corresponding components based on the Reliawind taxonomy. For operation data, recurrent neural networks are applied to model normal behaviors, which can learn the long-time temporal dependencies between various time series. Based on the estimation results, a two-stage threshold method is proposed as post-processing to determine operation conditions. The method evaluates the shift values deviating from the estimated behaviors and their duration time to attenuate minor fluctuations. A two-level condition monitoring system is constructed to apply the proposed fault detection framework, which targets to detect possible faults of components and conduct performance analysis of turbines. The fault detection framework is tested with the experience data from onshore wind farms. The results demonstrate that the framework can detect operational risks and reduce false alarms.
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| 2. |
- Alikhani, Parnian, et al.
(författare)
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Forecasting the Electrical Demand at the Port of Gävle Container Terminal
- 2021
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Ingår i: 2021 IEEE PES INNOVATIVE SMART GRID TECHNOLOGY EUROPE (ISGT EUROPE 2021). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 806-811
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Konferensbidrag (refereegranskat)abstract
- The port industry is transforming into a smart port thanks to technological advancements and environmental expectations. Developing a sustainable maritime transportation system and its beneficial electrification as a proven approach in emissions reduction are gathering momentum due to technological growth. Global containerization leads to high electricity demand at container terminals, and the electricity demand is highly dynamic and dependent on different operation processes. The approach of this paper is to forecast the hourly peak load demand and short-term electricity demand profile in a container terminal. The correctly forecasted electricity demand profile is crucial for less expensive and reliable power operation and planning. First, Artificial Neural Network (ANN)method is used to predict the container terminal baseload demand. Second, the worst-case simultaneous peak load is estimated. Third, the day-ahead load profile is modeled based on the handling operation scheduled for the day. The approach is implemented at the container terminal in Port of Gävle, and the results, including the baseload forecasting, the peak power demand, and the hourly load profile modeling by 2030, have been used in dialogue with the local energy company for the future predicted need of load.
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| 3. |
- Alikhani, Parnian, et al.
(författare)
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On the Reliability and Life Cycle Cost Analyses of Small-scale Standalone Solar Systems in Rural Areas
- 2021
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Ingår i: 2021 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 5-
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Konferensbidrag (refereegranskat)abstract
- In this paper, a three-step optimization approach is presented in order to obtain the optimal sizing of Standalone Photovoltaic (SPV) system. The main aim is to weigh the cost against the reliability of the system to make a smart design decision. The optimization approach has two objective functions to be minimized, Annual Lost Load (ALL) and Annual Life Cycle Cost (ALCC). The proposed method includes battery lifetime estimation, which is based on the active Depth of Discharge (DOD) of micro-cycles on the battery operation. The method has been applied to a remote area in Zambia. The results indicate that the introduced framework is capable of optimizing the system while satisfying the operational and economical requirements.
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| 4. |
- 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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| 5. |
- Bertling, Lina, Professor, 1973-, et al.
(författare)
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Lifetime Extension Options for Electrical Equipment
- 2023
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Ingår i: IET Conference Proceedings. - : Institution of Engineering and Technology. ; , s. 3185-3189
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Electrical equipment constitutes a considerable economic asset value for the distribution- and transmission system operators. Many network equipment in electrical networks have long intrinsic lifetimes most of which exceed 40 years. It is crucial for the economic performance of the operators to make optimal use of the equipment over time and therefore they should apply Asset Management (AM). Extending the life of equipment is one solution for AM which is in focus for this paper. This paper present results from a CIRED working group WG 2020-1 Lifetime extension options for electrical equipment. The WG identifies: life extension of equipment and/or substation solutions alternative to the renewal of equipment, good practices of lifetime extension options for electrical equipment and obstacles and/or limitations of electrical equipment life extension strategies.
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| 6. |
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| 7. |
- 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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| 8. |
- 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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| 9. |
- 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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| 10. |
- Cabus, Jose Eduardo Urrea, et al.
(författare)
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An Anomaly Detection Approach Based on Autoencoders for Condition Monitoring of Wind Turbines
- 2022
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Ingår i: 2022 17th international conference on probabilistic methods applied to power systems (PMAPS). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This research presents an anomaly detection approach based on autoencoders for wind turbine condition monitoring. The overall goal is to develop a methodology for assessing wind turbine health in order to enable preventative maintenance programs. First, SCADA signals are used as data input in the approach. The approach then examines the differences between the estimated values by the autoencoder models and the measured signals from the SCADA system. Next, the Kernel Density Estimation is used to determine the distribution of the expected output's error. Finally, to efficiently extract anomalous activity in the data, a novel dynamic thresholding approach is used. The outcome reveals that the method is capable of detecting potential abnormalities prior to the onset of a breakdown. It also verifies that the approach can alert operators to potential changes within wind turbines even when the alarm records show no alerts.
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