The impact of terrestrial radiation effects on the reliability of a smart grid

Author(s):  
Xiaoyin Yao ◽  
Hui Ni ◽  
G. Alonzo Vera
Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 644
Author(s):  
Michal Frivaldsky ◽  
Jan Morgos ◽  
Michal Prazenica ◽  
Kristian Takacs

In this paper, we describe a procedure for designing an accurate simulation model using a price-wised linear approach referred to as the power semiconductor converters of a DC microgrid concept. Initially, the selection of topologies of individual power stage blocs are identified. Due to the requirements for verifying the accuracy of the simulation model, physical samples of power converters are realized with a power ratio of 1:10. The focus was on optimization of operational parameters such as real-time behavior (variable waveforms within a time domain), efficiency, and the voltage/current ripples. The approach was compared to real-time operation and efficiency performance was evaluated showing the accuracy and suitability of the presented approach. The results show the potential for developing complex smart grid simulation models, with a high level of accuracy, and thus the possibility to investigate various operational scenarios and the impact of power converter characteristics on the performance of a smart gird. Two possible operational scenarios of the proposed smart grid concept are evaluated and demonstrate that an accurate hardware-in-the-loop (HIL) system can be designed.


2018 ◽  
Vol 10 (11) ◽  
pp. 4047 ◽  
Author(s):  
Jinchao Li ◽  
Tianzhi Li ◽  
Liu Han

In order to eliminate the impact of inter-regional differentiation of development demand on the objective evaluation of the development level of smart grid, this paper establishes the evaluation model of weight modification, transmission mechanism and combination of subjective and objective weights. Firstly, the Analytic Hierarchy Process method is used to calculate the weights of evaluation indices of effect layer and then the indices of development demand are used to modify the weights of them. The association analysis and the correlation coefficient are used to establish the weights conduction coefficient between the effect level and the base level. Then the subjective weights of the indices of the base layer are calculated. The objective weights of the indices of the base layer are obtained by using the entropy method. The subjective weights of the base layer and the objective weights obtained by the entropy method are averagely calculated, and the comprehensive weights of the evaluation indices of the base layer are obtained. Then each index is scored according to the weights and index values. Finally, the model is used to quantitatively inspect the level of development of smart grid in specific regions and make a horizontal comparison, which provides a useful reference for the development of smart grids. The relevant examples verify the correctness and validity of the model.


2014 ◽  
Vol 960-961 ◽  
pp. 841-844
Author(s):  
Yan Bin Li ◽  
Yun Li ◽  
Wei Guo Li

With the development of the smart grid , information network securityassessment affects the safe operation of the smart grid . In this paper, theimproved credibility theory and analytic hierarchy process , combined withstructural features of the smart grid network , From the wide area network ,access network, enterprise local network , local area network and the CPN-siteand home users to assess the impact of the five aspects of information networksfor smart grid security operation. And make the case for more security strategyto improve the reliability of the smart grid operation , thus providing a basisfor guiding the development and safe use of electricity grid users .


2017 ◽  
Vol 146 ◽  
pp. 308-320 ◽  
Author(s):  
D.X. Morales ◽  
Y. Besanger ◽  
S. Sami ◽  
C. Alvarez Bel

Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 14 ◽  
Author(s):  
Maricar Aguilos ◽  
Clément Stahl ◽  
Benoit Burban ◽  
Bruno Hérault ◽  
Elodie Courtois ◽  
...  

Warmer and drier climates over Amazonia have been predicted for the next century with expected changes in regional water and carbon cycles. We examined the impact of interannual and seasonal variations in climate conditions on ecosystem-level evapotranspiration (ET) and water use efficiency (WUE) to determine key climatic drivers and anticipate the response of these ecosystems to climate change. We used daily climate and eddyflux data recorded at the Guyaflux site in French Guiana from 2004 to 2014. ET and WUE exhibited weak interannual variability. The main climatic driver of ET and WUE was global radiation (Rg), but relative extractable water (REW) and soil temperature (Ts) did also contribute. At the seasonal scale, ET and WUE showed a modal pattern driven by Rg, with maximum values for ET in July and August and for WUE at the beginning of the year. By removing radiation effects during water depleted periods, we showed that soil water stress strongly reduced ET. In contrast, drought conditions enhanced radiation-normalized WUE in almost all the years, suggesting that the lack of soil water had a more severe effect on ecosystem evapotranspiration than on photosynthesis. Our results are of major concern for tropical ecosystem modeling because they suggest that under future climate conditions, tropical forest ecosystems will be able to simultaneously adjust CO2 and H2O fluxes. Yet, for tropical forests under future conditions, the direction of change in WUE at the ecosystem scale is hard to predict, since the impact of radiation on WUE is counterbalanced by adjustments to soil water limitations. Developing mechanistic models that fully integrate the processes associated with CO2 and H2O flux control should help researchers understand and simulate future functional adjustments in these ecosystems.


2019 ◽  
Vol 44 (4) ◽  
pp. 355-362 ◽  
Author(s):  
Tasawar Hayat ◽  
Ikram Ullah ◽  
Ahmed Alsaedi ◽  
Hamed Alsulami

Abstract The present work models MHD three-dimensional flow in a rotating channel. The energy expression is characterized by heat generation/absorption and radiation effects. Homogeneous-heterogeneous features are also accounted for. The obtained non-dimensional systems are numerically computed via the NDSolve based Shooting technique. Graphs are plotted to visualize the impact of various influential variables on velocity, temperature and concentration. In addition, skin friction and the Nusselt number are numerically estimated. Here temperature increases for increasing estimations of heat generation/absorption and radiation parameters. Furthermore, skin friction is reduced in the case of large Reynold number and rotation parameter.


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