Analysis of Prosumer Behavior in the Electrical Network

This article deals with the prosumer behavior, specifically on an on-grid electrical network that is connected to a larger synchronous electrical network, as well as an off-grid system. In the Simulink (Matlab) application, two models were constructed for this purpose. The modeling of the operation of the electrical network’s on-grid system takes place in one of the models. The simulation of the operation of the electrical network’s off-grid system takes place in the other. We examined the model’s behavior in the provided simulated period from the standpoint of transient states and qualitative indicators of electrical energy under various connection configurations in both systems. The simulations resulted in the possibility of incorporating new sources of energy accumulation, such as pumped storage hydropower plants based on energy storage systems (ESSs), and modifying the model to the user’s needs.

Probabilistic Long-Term Resilience of Bridges under Seismic and Deterioration Processes

Accurate long-term risk and resilience assessment of bridges are of paramount importance to aid rational decision-making under seismic hazards. There exist time-varying features within both earthquakes and structural deterioration. It has been found that the occurrence of large earthquakes is dependent on time due to energy accumulation, whereas the widely adopted homogeneous Poisson process assumes the time-independent occurrence of hazards. Besides, bridges can deteriorate over time due to environmental exposure, resulting in increased seismic vulnerability. The time-varying characteristics associated with both earthquakes and deterioration, which cause compound effects to structures, should be incorporated in long-term seismic risk and resilience assessment. In this paper, an approach for assessing the long-term resilience of bridges incorporating time-varying characteristics of earthquakes and deterioration is proposed. The Brownian Passage Time (BPT) model capturing energy accumulation and release is used to model time-varying characteristics of earthquakes. The bridge seismic vulnerability is computed in a time-variant manner considering deterioration. Subsequently, long-term bridge resilience is computed by considering earthquakes and deterioration occurring during the entire service life of bridges. The proposed approach is illustrated on a highway bridge under time-dependent seismic hazard and structural deterioration.

Acoustic Emission Features of Anthracite under the Influence of Loading Rate

Loading rate is an important impactor of the mechanical properties, as well as the deformation and failure mode of coal and rock. Using an RMT-301 rock mechanics tester and a Soft Island acoustic emitter, uniaxial compression and acoustic emission (AE) tests were carried out on coal samples under different loading rates. The results show that uniaxial compressive stress-strain curves of the rock samples each consist of four segments: compaction, elasticity, yield, and failure. As the loading rate increased from 0.01mm/s to 0.02mm/s, the peak strength rose, the post-peak deformability dropped, the brittle failure features of anthracite became more obvious, more AE events took place, and AE frequency increased. Energy analysis shows that, the faster the loading rate, the larger the AE count, the faster the energy accumulation, but the fewer the total energy accumulation.

Optimisation of Energy Accumulation for Renewable Energy Sources

This project focuses on optimisation of energy accumulation for various types of distributed renewable energy sources. The main goal is to prepare charging – discharging strategy depending on actual power consumption and prediction of consumption and production of utilised renewable energy sources for future period. The simulation is based on real long term data measured on photovoltaic system, wind power station and meteo station between 2004 – 2021. The data from meteo station serve as the input for the simulation and prediction of the future production while the data from PV system and wind turbine are used either as actual production or as a verification of the predicted values. Various parameters are used for trimming of the optimisation process. Influence of the charging strategy, discharging strategy, values and shape of the demand from the grid and prices is described on typical examples of the simulations. The main goal is to prepare and verify the system in real conditions with real load chart and real consumption defined by the model building with integrated renewable energy sources. The system can be later used in general installations on commercial or residential buildings.

Effects of Accumulated Energy on Nanoparticle Formation in Pulsed-Laser Dewetting of AgCu Thin Films

Ag50Cu50 films were deposited on glass substrates by a sputtering system. Effects of accumulated energy on nanoparticle formation in pulse-laser dewetting of AgCu films were investigated. The results showed that the properties of the dewetted films were found to be dependent on the magnitude of the energy accumulated in the film. For a low energy accumulation, the two distinct nanoparticles had rice-shaped/Ag60Cu40 and hemispherical/Ag80Cu20. Moreover, the absorption spectra contained two peaks at 700 nm and 500 nm, respectively. By contrast, for a high energy accumulation, the nanoparticles had a consistent composition of Ag60Cu40, a mean diameter of 100 nm and a peak absorption wavelength of 550 nm. Overall, the results suggest that a higher Ag content of the induced nanoparticles causes a blue shift of the absorption spectrum, while a smaller particle size induces a red shift.