• Energy Research
• 2016-2025close
• other engineering and technologies close
• UA close
• EC close
• KE close

The most severe failures in power grids are often characterized as cascading failures where an initial event triggers consequent failures all along the grid often leading to blackouts. Upon identifying a failure and its cascade potential, timely control actions should be performed by the grid operators to mitigate the effect of the cascade. These actions have to be delivered to one or more control devices, creating a dependency between the power grid and its control network. This paper examines the dependency of the operation of the power grid on the control network. Different from literature studies on failure control, our dependency model captures the impact of networking parameters. We formulate an algorithmic model that describes the impact of this dependency on cascade control. Based on this model, we propose an efficient cascade control algorithm using load shedding with consideration of delays in the communication network for power grids. Finally, we evaluate the impact of the power-communication network dependency with uncontrolled grids, ideal/simple control grids and our proposed control scheme. The results demonstrate that the proposed algorithm can significantly reduce the failure of power lines while sustaining larger power demand for users.

This paper reports the generalized results of computer simulation of physical processes at a rotor-disk film evaporating plant. Optimization of the operation mode cannot be achieved without establishing patterns in the course of physical processes. We have proposed a computer model of hydrodynamics that accounts for all the features, initial and boundary conditions. The results of computer simulations make it possible to adequately assess the effectiveness of using a rotor-disk film evaporating plant (RDFVP) for the concentration of heat-labile materials. We have established patterns in the course of physical processes within a structure of RDFVP by using computer simulation of hydrodynamics in the programming environment ANSYS and applying a k-e turbulence model. The result of simulation is the derived velocity fields of the concentrated fluid (w max =0.413 m/s) and the gas phase (w max =8.176 m/s), as well as the magnitude of values for shear stress τ=0.94·10 -6 Pa. It was established that the gas heat-carrier is characterized by the highly-turbulent flows with maximum values for kinetic energy TKE max =8.985·10 -1 m 2 /s 2 . The reliability of results is ensured by the correctness, completeness, and adequacy of physical assumptions when stating the problem and while solving it using the computer aided design system ANSYS. It has been established that the proposed structure is an effective alternative to equipment for the concentration of solutions. The data obtained could be used when designing heat-and-mass-exchange equipment for the highly efficient dehydration of thermolabile materials

The problems of environmental pollution in the conditions of high dust content in the air during the development of coal mines in the territory of the Czech Republic are considered. A mechanism for making managerial decisions was developed using an integrated approach using the new technological process Nastup Tušimice (DNT) aimed at eliminating pollutant emissions and managing workers in dusty conditions in mining operations. The recommendations of active and passive measures aimed at reducing dustiness in the process of coal mining have also been developed.

This research presents a 100% renewable energy (RE) scenario by 2050 with a high share of electric vehicles on the grid (V2G) developed in Ecuador with the support of the EnergyPLAN analysis tool. Hour-by-hour data iterations were performed to determine solutions among various features, including energy storage, V2G connections that spanned the distribution system, and long-term evaluation. The high participation in V2G connections keeps the electrical system available; meanwhile, the high proportions of variable renewable energy are the pillar of the joint electrical system. The layout of the sustainable mobility scenario and the high V2G participation maintain the balance of the electrical system during most of the day, simplifying the storage equipment requirements. Consequently, the influence of V2G systems on storage is a significant result that must be considered in the energy transition that Ecuador is developing in the long term. The stored electricity will not only serve as storage for future grid use. Additionally, the V2G batteries serve as a buffer between generation from diversified renewable sources and the end-use stage.

Abstract Protection devices are designed to provide high sensitivity to transients produced by undesirable conditions like lightning stroke, avoiding their operation under all tolerable events like switching operations. The problem of incorrect operation due to transient phenomena can be handled by two means, one is to allow the transients and provide additional logics in the relay, other means is to damp the oscillation from source side. Protection relays’ not always must trip or send a trip signal and sometimes, only an alarm is necessary. In this context, this research presents a fast and reliable formulation for transmission lines (TLs) switching operations and lightning strokes detection and identification. The proposed methodology is based on Principal Component Analysis (PCA) and Euclidean Norm (EN); by using PCA it is possible to determine that normal operation signals describe a very well defined Ellipsoidal Pattern (EP). In this manner, by calculating the Euclidean Norm (EN) among Principal Components (PCs) for each sample and the origin of the reference Ellipsoidal Pattern, switching operations and lightning strokes are detected and identified. Test results show that the proposed algorithm presents high success on phenomena detection and identification, presenting a high potential for online applications.

Nail polish, in particular gel nail polish, is the most used cosmetic product. The components of the gel polish, which determine both toxicity and consumer color properties, are pigments. Zn-Al layered double hydroxides intercalated with anionic food dyes are promising pigments for use in gel polish. The parameters of the samples of Orange Yellow S-intercalated Zn-Al (Zn:Al=4:1 and Zn:Al=2:1) hydroxides synthesized at pH=8 and pH=11 were studied. The crystal structure of the samples was studied by X-ray phase analysis and thermogravimetry, and the pigment properties – by the method of measuring and calculating color characteristics in the CIELab and XYZ systems. The color characteristics of gel nail polish samples prepared using synthesized pigments were studied in a similar way. X-ray phase analysis and thermogravimetry showed that Zn-Al-Orange Yellow S pigments synthesized at both Zn:Al ratios and pH were layered double hydroxides with the α-Zn(OH) 2 structure. The phenomenon of the decomposition of Zn-Al LDH to ZnO during the synthesis was revealed. As a result, all Zn-Al-Orange Yellow S pigment samples contained both layered double hydroxide and zinc oxide. It was shown that all samples of the Zn-Al-Orange Yellow S pigment obtained at pH 8 and 11 and the ratios Zn:Al=4:1 and Zn:Al=2:1 had high pigment characteristics and are promising for use in gel polish. The samples of gel nail polish with synthesized pigments have a red-orange color (сolor tone 595–604 nm) with high monochromaticity (color purity 63–75 %) and color saturation (48.7–58.3)

The assessment of greenhouse gases (GHGs) and air pollutants emitted to and removed from the atmosphere ranks high on international political and scientific agendas. Growing international concern and cooperation regarding the climate change problem have increased the need to consider the uncertainty in inventories of GHG emissions. The approaches to address uncertainty discussed in this special issue reflect attempts to improve national inventories, not only for their own sake but also from a wider, system analytic perspective. They seek to strengthen the usefulness of national emission inventories under a compliance and/or global monitoring and reporting framework. The papers in this special issue demonstrate the benefits of including inventory uncertainty in policy analyses. The issues raised by the authors and featured in their papers, along with the role that uncertainty analysis plays in many of their arguments, highlight the challenges and the importance of dealing with uncertainty. While the Intergovernmental Panel on Climate Change (IPCC) clearly stresses the value of conducting uncertainty analyses and offers guidance on executing them, the arguments made here in favor of performing these studies go well beyond any suggestions made by the IPCC to date. Improving and conducting uncertainty analyses are needed to develop a clear understanding and informed policy. Uncertainty matters and is key to many issues related to inventorying and reducing emissions. Considering uncertainty helps to avoid situations that can create a false sense of certainty or lead to invalid views of subsystems. Dealing proactively with uncertainty allows for the generation of useful knowledge that the international community should have to hand while strengthening the 2015 Paris Agreement, which had been agreed at the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC). However, considering uncertainty does not come free. Proper treatment of uncertainty is demanding because it forces us to take the step from “simple to complex” and to grasp a holistic system view. Only, thereafter, can we consider potential simplifications. That is, comprehensive treatment of uncertainty does not necessarily offer quick or easy solutions for policymakers. This special issue brings together 13 papers that resulted from the 2015 (4th) International Workshop on Uncertainty in Atmospheric Emissions, in Cracow, Poland. While they deal with many different aspects of the uncertainty in emission estimates, they are guided by the same principal question: “What GHGs shall be verified at what spatio-temporal scale to support conducive legislation at local and national scales, while ensuring effective governance at the global scale?” This question is at the heart of mitigation and adaptation. It requires an understanding of the entire system of GHG sources and sinks, their spatial characteristics and the temporal scales at which they react and interact, the uncertainty (accuracy and/or precision) with which fluxes can be measured, and last but not least, the consequences that follow from all of the aforementioned aspects, for policy actors to frame compliance and/or global monitoring and reporting agreements. This bigger system context serves as a reference for the papers in the special issue, irrespective of their spatio-temporal focus, and is used as a guide for the reader.