Renewable energy sources are gradually becoming useful in mining industry. They are actively used in remote, sparsely populated areas to power shift settlements, geological and meteorological stations, pipeline equipment, mobile cell towers, helicopter pads lighting, etc. In comparison with diesel generators, systems with renewable sources do not require fuel transportation, have short payback periods and flexible configuration for different categories of electrical loads. The main obstacles to their spread are instability of generation and high cost of produced electricity. One of the possible ways to solve these problems is to develop new technologies, increase power density of generators and energy storage systems. The other way represents energy saving and rational use of affordable resources. The new solutions for implementation of the second method are proposed in this work. The object of the study is autonomous DC electrical complex with photovoltaic and wind power sources. In such systems the generated power from renewable sources is transferred to consumers via intermediate DC bus, the voltage level of which affects the power losses in the process of power transmission. The vast majority of complexes have a problem that their DC bus voltage is constant, while the optimum voltage level with lowest losses varies depending on the generated and consumed power. Therefore, electrical complexes potentially lose a part of the transmitted energy. To avoid this, a special algorithm was added to automatically adjust DC bus voltage to optimum level according to changes in working conditions. An additional contribution to efficiency improvement can be made by dynamic change of operating frequency in power converters depending on their load. The evaluation based on results of computer simulation showed that in a complex with rated power 10 kW active power losses during its lifetime can be reduced by 2-5 %.
A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal technologies. The application of electrothermal processes offers many advantages from technological, ecological and economical point of view. Although the technology level of the electro heating and melting installations and processes used in the industry today is very high, there are still potentials for improvement and optimization due to the increasing complexity of the applications and the strong requirements regarding the performance and quality of the products but also regarding the reduction of time and costs for the development of new processes and technologies. In this paper recent applications and future development trends for efficient heating and melting by electrothermal technologies in metallurgical processes are described along selected examples like induction heating for forging or rolling of billets, heat treatment of strips and plates, press-hardening processes, induction surface hardening of complex geometries, induction welding as well as induction melting processes.
The possible options for the integration of telecommunications and electrical systems of mining enterprises are considered. Based on an analysis of the current state and prospects for the development of telecommunications systems, various technical solutions are proposed for sharing the power supply networks available in mines and underground structures in order to solve the problems of telecommunication, automate process control and ensure the safety of operations. The analysis of the possibilities of applying the PLC technology in underground structures and mines for solving specific telecommunication problems has been carried out, and examples of their possible technical and hardware implementation are given.
Subjects of the research are industrial electric drives, witch maintain the operation of main actuating units of production machines and installations during the development of mineral resource deposits. The goal is to research the possibility to ensure the energy decoupling of industrial electric drives and electric grid by means of structural implementation of active rectifiers into frequency converters. The main purpose of energy decoupling is to eliminate the negative impact of low quality electric energy and changes in energy parameters on electric drive operation. In order to accomplish energy decoupling of electric drive with active rectifier, methods of mathematical and simulation modeling with mathematical application software package were used. The integrated simulation model with two electric drives, including active rectifier (energy decoupled electric drive) and diode rectifier (standard type electric drive), were created. Simulation model is provided with tools for oscillographic testing and analysis of the impact of power quality parameters on frequency converters and drive motors operation. The analysis of effectiveness of energy decoupling by means of active rectifier of frequency converter shows that drive motor completely retains the stability and controllability of rotation frequency and torque during the changes of power quality parameters in electric grid. The use of active rectifier allows to ensure the operation of electric drive in required mode in case of voltage decrease by 30 % with normative value of 5-10 %, i.e. energy decoupling provides high stability margin for voltage. Electric drive with active rectifier ensures energy decoupling in case of asymmetry of supply voltage. The control of mechanical variables of induction motor during offsets in amplitude and frequency in all phases of electric grid is ensured to be on required level.
The article describes the main methodological aspects of designing multispectral optoelectronic devices intended for remote sensing of overhead power lines. Based on proposed indicators and detection criteria a method for selecting operating spectral zones for these devices is suggested, methods of researching into their efficiency and the results of simulating the process of their operation are described.
