Fixed and mobile energy storage coordination optimization method for enhancing photovoltaic integration capacity considering voltage offset

Mobile energy storage has the characteristics of strong flexibility, wide application, etc., with fixed energy storage can effectively deal with the future large-scale photovoltaic as well as electric vehicles and other fluctuating load access to the grid resulting in the imbalance of supply and demand. To this end, this paper proposes a coordinated two-layer optimization strategy for fixed and mobile energy storage that takes into account voltage offsets, in the context of improving the demand for local PV consumption. Among them, the upper layer optimization model takes into account the minimum operating cost of fixed and mobile energy storage, and the lower layer optimization model minimizes the voltage offset through the 24-h optimal scheduling of fixed and mobile energy storage in order to improve the in-situ PV consumption capacity. In addition, considering the multidimensional nonlinear characteristics of the model, the interaction force of particles in the Universe is introduced, and the hybrid particle swarm-gravitational search algorithm (PSO-GSA) is proposed to solve the model, which is a combination of the individual optimization of the particle swarm algorithm and the local search capability of the gravitational search algorithm, which improves the algorithm’s optimization accuracy. Finally, the feasibility and effectiveness of the proposed model and method are verified by simulation analysis with IEEE 33 nodes

Whole-genome resequencing of 472 Vitis accessions for grapevine diversity and demographic history analyses

Despite the importance of grapevine cultivation in human history and the economic values of cultivar improvement, large-scale genomic variation data are lacking. Here the authors resequence 472 Vitis accessions and use the identified genetic variations for domestication history, demography, and GWAS analyses

Coupled modeling of hydromechanical behavior of quasi-brittle porous rocks

Cette étude porte sur une modélisation micromécanique du comportement poromécanique des roches poreuses quasi-fragiles endommagées par une distribution de microfissures. Le cadre général retenu est celui de l'approche par changement d'échelles dans le cadre de la thermodynamique des processus irréversibles. Les propriétés mécaniques effectives sont déterminées par une technique d'homogénéisation linéaire en se basant sur la solution du problème d inclusion d'Eshelby. Le glissement frottant le long des surfaces de microfissures fermées est considéré comme un processus de dissipation irréversible et responsable de l'évolution de l'endommagement. Un critère de frottement de type Coulomb est utilisé et un critère d'endommagement basé sur le taux de restauration d'énergie est proposé. La deuxième partie du mémoire vise à étendre la modélisation micromécanique à la description du couplage poromécanique des roches saturées. L'influence de la pression du fluide sur le glissement est prise en compte en introduisant une notion de contrainte effective au niveau microscopique. Nous démontrons que le glissement frottant peut engendrer une dilatance volumique conduisant à une réduction de la pression du fluide. Les résultats numériques sont comparés aux données expérimentales dans les essais drainés et non drainés en compression triaxiale. La dernière partie de cette thèse porte sur la modélisation hydromécanique des fractures rocheuses sous contrainte normale. Des études expérimentales et des modélisations numériques sont effectuées. Un coefficient de Biot généralisé, fonction de l'ouverture de fractures, est introduit pour décrire le comportement poromécanique couplé.This study concerns a micromechanics-based modeling of poromechanical behaviors of quasi-brittle porous rocks. The general framework adopted is that of up-scaling technique combined with irreversible thermodynamics. We first determine the effective property of quasi brittle rocks weakened by microcracks via the rigorous Eshelby-based homogenization method. The frictional sliding along surfaces of closed microcracks is interpreted as an irreversible dissipation process and responsible for the induced damage. An elastoplastic damage model is formulated with the inelastic strain inherently coupled with damage evolution. A Coulomb-type friction criterion serving as plastic yielding function and a strain energy release rate based damage criterion are proposed. The second part aims at extending the micromechanical modeling to poromechanical behavior of saturated porous rocks. The influence of fluid pressure is taken into account in the friction criterion through the concept of local effective stress. It is also manifested that the frictional sliding between crack surfaces generates volumetric dilatancy and causes reduction in fluid pressure. Applications of the proposed model to typical brittle rocks are presented and compared with experimental data in both drained and undrained triaxial tests. The last part of this dissertation deals with the hydromechanical modeling of single fracture subject to normal stress. Both experimental studies and theoretical modeling are carried out. The generalized Biot coefficient, in the form of a function of the fracture displacement, is introduced to describe the coupled behavior between fracture deformation and pore fluid pressure.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

A dual-porosity model for analysis of temperature effects on hydro-mechanical behaviour of GMZ bentonite under confined conditions

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