Operation mode selection algorithm development of a wind-diesel power plant supply complex

The power supply system is affected by external disturbances, so it should be stable and operate normally in compliance with power quality standards. The power supply system goes into abnormal modes operation when, after a short-term failure or disturbance, it does not restore normal mode. The electrical complex, which includes a wind power plant, as well as a battery and a diesel generator connected in parallel, is able to provide reliable power supply to consumers which meets the power quality indicators. The article develops an algorithm that is implemented by an automatic control system to select the operating mode depending on climatic factors (wind) and the forecast of energy consumption for the day ahead. Forecast data is selected based on the choice of the methods, which will have the smallest forecast error. It is concluded that if the energy consumption forecast data is added to the automatic control system, then it will be possible to increase the efficiency of the power supply complex. In the developed algorithm the verification of normal and abnormal modes of operation is considered based on the stability theory. The criteria for assessing the normal mode of operation are identified, as well as the indicators of the object’s load schedules for assessing the load of power supply sources and the quality standards for power supply to consumers for ranking the load by priority under critical operating conditions and restoring normal operation are considered

Energy efficiency in the mineral resources and raw materials complex

Energy efficiency and energy saving at all times and especially at the present stage of development of industry and economy have played an extremely important role. Regardless of which countries and according to what criteria they build energy development plans, energy efficiency and energy saving are always a priority. This fully applies to the mineral resources complex, in which energy consumption as a whole makes up a large share of total consumption. The resources mined in the mineral resources complex are themselves a source of energy. The energy sector is evolving in many ways. Many scientific works, the results of which are reflected in publications, confirm the relevance of research in the energy efficiency field. But the approach to individual decisions in the mineral resource industry is specific and it is worth of separate consideration. Recently, much attention has been paid to “green energy” and renewable energy sources. However, energy efficiency in the field of traditional generation and consumption remains an urgent problem and its solution is in constant development. One of the main directions for improving energy efficiency is the development of autonomous systems for the electrical and thermal power engineering. All these problems are reflected in a special volume of the Journal of the Mining Institute, the articles are divided into four sections: energy efficiency of the electric drive in the mineral resources complex (MRC); energy efficiency of industrial plants and enterprises in MRC; power quality and renewable sources in MRC; autonomous power supply systems in MRC. The presented articles contain valuable material from the scientific and practical points of view and can form the basis for further research in the energy efficiency field

Multi-terminal dc grid overall control with modular multilevel converters

This paper presents a control philosophy for multiterminal DC grids, which are embedded in the main AC grid. DC transmission lines maintain higher power flow at longer distances compared with AC lines. The voltage losses are also much lower. DC power transmission is good option for Russian north. Arctic seashore regions of Russia don't have well developed electrical infrastructure therefore power line lengths are significant there. Considering above it is possible to use DC grids for supply mining enterprises in Arctic regions (offshore drilling platforms for example). Three different control layers are presented in an hierarchical way: local, primary and secondary. This whole control strategy is verified in a scaled three-nodes DC grid. In one of these nodes, a modular multilevel converter (MMC) is implemented (five sub-modules per arm). A novel model-based optimization method to control AC and circulating currents is discussed. In the remaining nodes, three-level voltage source converters (VSC) are installed. For their local controllers, a new variant for classical PI controllers are used, which allow to adapt the values of the PI parameters with respect to the measured variables. Concerning the primary control, droop control technique has been chosen. Regarding secondary level, a new power flow technique is suggested. Unbalance conditions are also verified in order to show the robustness of the whole control strategy

The influence of solar energy on the development of the mining industry in the Republic of Cuba

Cuba is traditionally considered a country with an underdeveloped industry. The share of the mining and metallurgical industries in the gross industrial production of the republic is small – about 3 % of GDP. The development of deposits and the extraction of nickel ores is an important sector of the economy of the Republic of Cuba, since the largest reserves of nickel and cobalt on the North American continent are located on the territory of the country. The development of the country energy system can serve as a growth factor in this sector of the economy. Due to climatic features and impossibility of integrating new capacities into the energy system through the construction of hydroelectric power plants, solar energy is a promising direction. Determining the feasibility of using solar tracking systems to increase the generation of electricity from solar power plants is one of the main challenges faced by engineers and renewable energy specialists. Currently, there are no solar tracking systems in Cuba that can provide information to assess the effectiveness of this technology in the country. The lack of the necessary technologies, as well as the high cost of developing solar power plants with tracking systems, limit the widespread introduction of such complexes. Hence follows the task of creating an inexpensive experimental model that allows assessing the effectiveness of tracking systems in specific weather conditions of the Republic of Cuba. This model will allow in future to increase the efficiency of electrical complexes with solar power plants, which provide power supply to the objects of the mineral resource complex and other regions