-
Date submitted2021-01-20
-
Date accepted2021-03-15
-
Date published2021-04-26
Improving the quality of electricity in the power supply systems of the mineral resource complex with hybrid filter-compensating devices
- Authors:
- Yurii A. Sychev
- Roman Yu. Zimin
The urgency and necessity of choosing and justifying the structures of hybrid filter-compensating devices based on series and parallel active filters to improve the quality of electricity in the power supply systems of enterprises of the mineral resource complex is shown. Mathematical models of hybrid filter compensating devices based on parallel and series active filters have been developed. Based on these mathematical models, computer simulation models of the indicated hybrid structures have been developed. The results of simulation showed the effectiveness of the correction of power quality indicators in terms of reducing the level of higher harmonics of current and voltage, as well as voltage deviations. The degree of influence of filter-compensating devices on the power quality indicators, which determine the continuity and stability of the technological process at the enterprises of the mineral resource complex, have been revealed. It has been established that a hybrid filter-compensating device based on a parallel active filter can reduce the level of higher harmonics of current and voltage by more than 90 and 70 %, respectively, and based on a series active filter, it can reduce the level of higher harmonics of voltage by more than 80 %. Based on the simulation results, the possibility of compensating for the reactive power of a hybrid structure based on parallel active and passive filters has been revealed. The possibility of integrating hybrid filter-compensating devices into more complex multifunctional electrical systems for the automated improvement of the quality of electricity is substantiated, as well as the expediency and prospects of their use in combined power supply systems based on the parallel operation of centralized and autonomous sources of distributed generation.
-
Date submitted2018-12-25
-
Date accepted2019-03-02
-
Date published2019-06-25
Non-linear electrical load location identification
- Authors:
- S. Pirog
- Ya. E. Shklyarskiy
- A. N. Skamyin
The article discusses the issues of identifying the location of non-linear loads in electrical networks which makes the main contribution to the distortion of the non-sinusoidal voltage and current in the distribution network of an industrial enterprise, including mining enterprises. The existing methods for determining the location of the source of higher harmonic components in voltage and current are considered, their advantages and disadvantages are revealed. The main disadvantages of the methods used include the low accuracy and incorrectness of their use in existing enterprises. When developing a new method, the authors were faced with the task of simplicity of its use in the conditions of industrial operation of electrical equipment and the absolute correctness of the results obtained. The proposed method of identifying the source of higher harmonics is based on the variation of the parameters of the power system, in particular, the change in resistance of power transformers taking into account their transformation ratio. It is shown that by varying the transformation ratio during regulation under load, the total coefficient of the harmonic components of the voltage changes. Based on the constructed dependencies, the variation of the derivative of this function with different variations of the parameters of sources of higher harmonics is analyzed and a method is developed that allows determining the share contribution of consumers to the total harmonic component of the voltage.
-
Date submitted2017-08-26
-
Date accepted2017-11-10
-
Date published2018-02-22
On enhancement of cooperation between universities for implementation of the program «Sustainable development–2030»
- Authors:
- P. Ochirbat
- B. Chinzorig
The article is focused on one of the pressing issues of our time – the international training of qualified personnel in higher education institutions with the aim of developing a stable economic system of the state, the main elements of which are interrelated stages of economic activity (exploration, prospecting, extraction, processing, and use of mineral resources). The question of the contribution and role of universities of different countries cooperating in the sphere of sustainable development of this sector is considered. The necessity of practical solution of this task for the implementation of UNESCO's program «Sustainable Development – 2030» is determined. In this relation, the concept of «sustainable development», its philosophical, scientific-theoretical and cultural aspects are considered, the special significance of the connection between the sustainable development of society and its individual fragments with modern education is emphasized. It is stated that education, in the context of sustainable development, should be anticipating, advancing and open. Given the current trends in higher education, it is possible to mention the work carried out by the Mining Institute of the Mongolian State University of Science and Technology in the direction of international cooperation.
-
Date submitted2009-10-28
-
Date accepted2009-12-25
-
Date published2010-09-22
Prediction of dynamic manifestations of rock pressure in the all over automated longwalls
- Authors:
- M. Roiter
- V. Kurfyurst
- K. Mairkhofer
- J. Veksler
The support control system «MARCO» has programs for the estimation of a geomechanical situation around the face by continuous measurements of pressure in the legs of support. The analysis of the face convergence allows to predict the possibility of a rock burst. The seam’s reaction on the shearer or plough influence may be the dangerous main roof collapse into the mine-out space of longwall.
-
Date submitted2009-10-18
-
Date accepted2009-12-17
-
Date published2010-09-22
Reuse of development workings as an element of providing the effective coal output
- Authors:
- M. A. Ilyashov
The article contains the results of application in a coal mine of a combined way for protection and support of development workings. This method combines a frame support, anchors and a cast support strip erected behind the longwale. The geomechanical substantiation of technological parameters, regulations and the field for efficient use of this method are given. Its introduction has allowed to increase the loads on longwale and to lower labour content and expenses for maintenance of butt entries.
-
Date submitted2009-10-26
-
Date accepted2009-12-27
-
Date published2010-09-22
Support of geodynamic safety in mining of the Khibini deposits
The paper deals with the problems of geodynamics in mining of the Khibini deposits. Description is given to the complex of organizational-technical arrangements for provision of geodynamic safety at the Apatit Co and to principal trends of its development.
-
Date submitted2009-07-25
-
Date accepted2009-09-09
-
Date published2010-04-22
The use of data on stress-strain state of rock mass in solutions of mining-and-technical tasks on the example of the Tishin ore mine
The Permion State Technical University and ASE «VNIItsvetmet» have carried out in situ measurements of stress-strain state at the Tishinsky lead-zinc ore deposit. Measurements and interpretation of deformations and stresses caused by excavation were used. Complex of researches made it possible to solve some important problems for safeguarding effective and secure ore production ore on deep level.
-
Date submitted1951-07-01
-
Date accepted1951-09-16
-
Date published1952-12-23
On the calculation of eigenvalues by the method of steepest descent
- Authors:
- M. Sh. Birman
L. V. Kantorovich proposed a new direct method for solving problems of the calculus of variations, which he called the steepest descent method. As L. V. Kantorovich showed, the method can be successfully used for the approximate solution of linear functional equations in a Hilbert space. In addition, L. V. Kantorovich applied the steepest descent method to the problem of eigenvalues of completely continuous operators. In application to this problem, the method consists of the following. In this note, a proof of the convergence of the process is given without the assumption of closeness of x0 to x*. In addition, a comparison of the steepest descent method with the known iterative method for calculating eigenvalues is made, and a multi-step version of the method under consideration is investigated. In what follows, the assumption that m = 0 is not used.