Model based analysis of the EU power system based on RES — A case study for Greece and Germany

Author(s):  
Pantelis Capros ◽  
Marilena Zampara ◽  
Nikos Tasios ◽  
Dimitris Papadopoulos ◽  
Christoph Kost ◽  
...  
Author(s):  
Matthew O. T. Cole ◽  
Lawrence Hawkins

For rotors supported by active magnetic bearings (AMBs), clearance bearings are commonly used to provide backup support under loss of AMB functionality. Test data from real machines shows that rotor vibration during touchdown on backup bearings may involve steady forward whirling at a sub-synchronous frequency. This excitation is believed to be due to friction forces transmitted between the rotor and a bearing end-face under axial load. This paper proposes a new analytical approach to model and predict such friction-driven forward whirl behaviors. A set of constraint equations are derived that relate a circular whirl motion of arbitrary orbital speed to the frequency response functions of the rotor-housing structure. This model is coupled with an evaluation of Coulomb friction associated with slip between the rotor and the supporting end-face of a thrust bearing. The resulting equations can be used to compute a set of possible whirl motions via a root-finding procedure. A case study is undertaken for a 140 kW energy storage flywheel. Model-based predictions are compared with measured data from spin-down tests and show a good level of agreement. The study confirms the role of friction-related forces in driving forward-whirl response behaviors. It also highlights the key role of housing and machine support characteristics in response behavior. This influence is shown to be complex and not open to simple physical interpretation. Therefore, the proposed analytical method is seen as a useful tool to investigate this influence while avoiding the need for time consuming numerical simulations.


Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 574
Author(s):  
Zeyong Jiang ◽  
Tingdi Zhao ◽  
Shihai Wang ◽  
Hongyan Ju

With the development of integrated modular avionics (IMA), the dynamic reconfiguration of IMA not only provides great advantages in resource utilization and aircraft configuration, but also acts as a valid means for resource failure management. It is vital to ensure the correction of the IMA dynamic reconfiguration process. The analysis of the dynamic reconfiguration process is a significant task. The Architecture Analysis & Design Language (AADL) is widely used in complicated real-time embedded systems. The language can describe the system configuration and the execution behaviors, such as configuration changes. Petri net is a widely used tool to conduct simulation analysis in many aspects. In this study, a model-based analyzing method with multiple constraints for the IMA dynamic reconfiguration process was proposed. First, several design constraints on the process were investigated. Second, the dynamic reconfiguration process was modeled based on the AADL. Then, a set of rules for the transition of the model from AADL to Petri net was generated, and the multi-constraints proposed were incorporated into Petri net for analysis. Finally, a simulation multi-constraint analysis with Petri net for the process of IMA dynamic reconfiguration was conducted. Finally, a case study was employed to demonstrate this method. This method is advantageous to the validity of IMA dynamic reconfiguration at the beginning of the system design.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2309 ◽  
Author(s):  
Christos Agathokleous ◽  
Jimmy Ehnberg

A significant amount of conventional power plants in the European power system is anticipated to be replaced by solar and wind power in the future. This may require alternative sources for inertia support. The purpose of the paper is to learn about the consequences on the frequency deviation after a fault in the European power system when more wind and solar are introduced and when wind is considered as a possible provider of inertia. This study quantifies the expected maximum requirement for additional inertia in the future European power system up to 2050. Furthermore, we investigated the possibility of wind power to meet this additional need by providing emulated inertia. The European power system of the EU-28 countries has been clustered to the five synchronous grids, UCTE, Nordic, UK, Baltic and Irish. The future European energy mix is simulated considering twelve different scenarios. Production units are dispatched according to their expected environmental impacts, which closely follow the minimum natural contribution of inertia, in descending order. The available capacity for all the types of production is considered the same as the installed. For all the simulated scenarios the worst case is examined, which means that a sudden disconnection of the largest production unit of the dispatched types is considered. Case study results reveal that, in most cases, additional inertia will be required but wind power may fully cover this need for up to 84% of all simulated horizons among all the scenarios on the UCTE grid, and for up to 98%, 86%, 99% and 86% on the Nordic, UK, Baltic and Irish grids, respectively.


2011 ◽  
Vol 44 (1) ◽  
pp. 3753-3758 ◽  
Author(s):  
Dániel A. Drexler ◽  
Levente Kovács ◽  
Johanna Sápi ◽  
István Harmati ◽  
Zoltán Benyó

2012 ◽  
Vol 1 (2) ◽  
pp. 76-84 ◽  
Author(s):  
Pantelis Capros ◽  
Nikolaos Tasios ◽  
Alessia De Vita ◽  
Leonidas Mantzos ◽  
Leonidas Paroussos

Author(s):  
Ole J. Mengshoel ◽  
Mark Chavira ◽  
Keith Cascio ◽  
Scott Poll ◽  
Adnan Darwiche ◽  
...  

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Matthew O. T. Cole ◽  
Lawrence Hawkins

For rotors supported by active magnetic bearings (AMBs), clearance bearings are commonly used to provide backup support under loss of AMB functionality. Test data from real machines shows that vibration during touchdown on backup bearings may involve steady forward whirling of the rotor with a subsynchronous frequency. This excitation is believed to be due to friction forces transmitted between the rotor and a bearing end-face under axial load. This paper proposes a new analytical approach to model and predict such friction-driven forward whirl behaviors. A set of constraint equations are derived that relate a circular whirl motion of arbitrary orbital speed to the frequency response functions for the rotor-housing structure. This model is coupled with an evaluation of Coulomb friction associated with slip between the rotor and the supporting end-face of a thrust bearing. The resulting equations can be used to compute a set of possible whirl motions via a root-finding procedure. A case study is undertaken for a 140 kW energy storage flywheel. Model-based predictions are compared with measured data from spin-down tests and show a good level of agreement. The study confirms the role of friction-related forces in driving forward-whirl response behaviors. It also highlights the key role of housing and machine support characteristics in response behavior. This influence is shown to be complex and not open to simple physical interpretation. Therefore, the proposed analytical method is seen as a useful tool to investigate this influence while avoiding the need for time consuming numerical simulations.


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