Weather data errors analysis in solar power stations generation forecasting

The paper presents a short-term forecasting model for solar power stations (SPS) generation developed by the authors. This model is based on weather data and built into the existing software product as a separate short-term forecasting module for the SPS generation. The main problems associated with forecasting the SPS generation on cloudy days were revealed in the framework of authors' research, which is due not to the error of the developed model but to the use of the same learning sample for both solar and cloudy days. This paper contains analysis of the main problems related to the learning sampling, samples pattern, quality and representativeness for forecasting the SPS generation on cloudy days. Besides, the paper includes a calculation example performed for the existing SPS and a detailed analysis of the forecast generation on cloudy days based on the actual weather provider data. © The Authors, published by EDP Sciences

Siting and sizing of distributed generation with integrated project feasibility analysis

Научно-исследовательская работа выполнена по договору № 1.2.1.5./10 от 27 мая 2013 г. В ходе выполнения была разработана методика оценки целесообразности строительства объекта малой генерации, позволяющая качественно и количественно оценить влияние генерирующего источника на энергосистему, а также оценить опти-мальную точку подключения и мощность генерирующего источника в соответствии с перечнем разработанных технико-экономических критериев.The research work was carried out under contract № 1.2.1.5./10 of 27 May 2013. The final report contains the detailed description of the methodology, developed for distributed generation implementation feasibility assessment. Proposed approach makes it possible to provide quantitative and qualitative assessment of distributed generation influence on the power system, as well as to assess the optimal point of power generation unit connection in accordance with the list of technical and economic criteria.Программа развития УрФУ на 2013 год (п.1.2.2.3

An experience of distant consumers power supply by means of the renewables given specific conditions

Local renewable energy resources (RES) are often considered as an alternative to the conventional power supply by means of power lines. This is an urgent approach for rural electrification if there are long distances from main substations, and distribution feeders’ construction and service is not cost-effective for grid companies. Nevertheless, the real potential for RES implementation at some regions could be limited by economic, geographical and climatic factors especially. The paper gives a review of the experience of power supply type selection for distant consumers given the specific northern continental conditions. The main goal of the paper is the methods estimating technical and economical efficiency of power supply system alternatives including centralized power supply and standalone microgrid implementation to select suitable power supply variant. © 2016, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved.Ministry of Education and Science of the Russian Federation, Minobrnauka: 13.1928.2014/KThe work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006 and the Ministry of Education and Science of the Russian Federation (in the framework of state assignment, №13.1928.2014/K (project №1928))

Remnants of dark matter clumps

What happened to the central cores of tidally destructed dark matter clumps in the Galactic halo? We calculate the probability of surviving of the remnants of dark matter clumps in the Galaxy by modelling the tidal destruction of the small-scale clumps. It is demonstrated that a substantial fraction of clump remnants may survive through the tidal destruction during the lifetime of the Galaxy if the radius of a core is rather small. The resulting mass spectrum of survived clumps is extended down to the mass of the core of the cosmologically produced clumps with a minimal mass. Since the annihilation signal is dominated by the dense part of the core, destruction of the outer part of the clump affects the annihilation rate relatively weakly and the survived dense remnants of tidally destructed clumps provide a large contribution to the annihilation signal in the Galaxy. The uncertainties in minimal clump mass resulting from the uncertainties in neutralino models are discussed.Comment: 13 pages, 6 figures, added reference

Electrical load forecasting

Some long-term design activities are based on electrical load forecasting. Forecasting errors result in the wrong decisions being made in the future. At present there are three widely used methods of forecasting: the method based on enlarged specific indexes (ESI), the econometric method and the self-sufficient method. All of these methods have their own disadvantages and errors in estimation. The main reasons for errors in areas such as objective reasoning, changes in production technology, the lack of reliable long-term forecasting for economy development and consumer infraction of load schedule are determined in this paper and an objective estimation for the forecasted error of different spheres of application is made. This work aims to determine a sphere of application for each of these methods and to develop a principal of combined application, so that they may decrease forecasting error. The purpose of this work consists of the creation of an electrical load forecasting method to obtain more reliable data for the different time periods and territory. A new method is presented, based on calculations carried out. Recommendations for all existing methods are given with reference to the calculations and the way that the combined application of several methods was introduced to increase the reliability of a forecast. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Fuzzy neural networks' application for substation integral state assessment

This paper addresses the problems connected with fuzzy neural networks' application in equipment technical state assessment problems at electrical substations. This paper discusses the main principles of fuzzy neural network formation and its construction algorithm. Also, the case study for the determination of fuzzy neural network synaptic weights for the unit "disconnector" on the basis of technical diagnostic statistical data and tests is presented. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

PMU-based informational support of power system control tasks

Up-to-date wide area measurement systems (WAMS) based on phasor measurement units (PMU) appeared at the very end of the 20th century. Under present-day conditions, WAMS serve as the basis for information-measuring systems, which significantly improve power system control and operation. In practice, WAMS are mostly used for power system stability control and transient monitoring and visualization. This paper discusses the new opportunities for power system control quality improvement, resulting from PMU application for power system steady-state parameters' assessment. Firstly, better control is provided by online equivalent circuit parameters' identification using PMU measurement data and taking into account FACTS and other shunt and series compensation equipment. Secondly, the paper addresses the problems of "nodal" identification, which have taken on great importance recently due to the intensive development of small-scaled distributed generation. Based on PMU measurements of nodal voltages and incident transmission lines' electric currents, one can obtain online steady-state load characteristics, which can be used for dispatch control applications. Moreover, PMUs provide superaccelerated power flow calculations, which are of crucial importance for emergency automation, adjusted for prior operation. Such principles of emergency automation consist of the quick determination of control actions, aimed at power system stability maintenance in cases of any programmed faults' occurrence. It is known that such control is carried out by means of power flow calculations based on remote metering data. The proposed application and allocation of PMUs in the power system by means of combinatorial matrix transformation to triangle form give the possibility to perform accelerated node-voltage analysis without equivalent circuit simplification. All the calculations are verified using IEEE test networks. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Effect of grain refinement on deformation behavior of technical grade titanium under tension

The paper deals with the study on the impact of grain refinement by severe plastic deformation upon the microstructure, as well as deformation and fracture behavior under tensile loading of technical grade titanium. The microstructure of coarse- and ultra-fine grain technical grade titanium was investigated by optical, transmission electron microscopy and X-ray diffraction. In situ monitoring of deformation behavior was conducted by means of acoustic emission and digital image correlation. Scanning electron microscopy was employed for fracture surface observation. The results of the tensile tests have revealed significant growth in ultimate strength and decrease of ductility due to grain-boundary strengthening. The experimental data obtained allow one to get the appropriate understanding of the mechanisms responsible for variation of mechanical properties and fracture patterns as well as to attain quantitative estimation of strain localization induced by the grain refinement