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Date submitted2018-10-27
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Date accepted2019-01-04
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Date published2019-04-23
Application of an active rectifier used to mitigate currents distortion in 6-10 kV distribution grids
The paper addresses issues of using the active rectifier in partially loaded variable frequency drive as active filter in the conditions of non-sinusoidal current and voltage disturbances caused by the presence of high-power non-linear load in the grid. The topology of transformless three-level converter for 6-10 kV suitable for proposed solution has been presented and its mathematical model has been de-rived. Based on the model, the direct power control algorithm with ability to compensate non-linear currents has been designed. The investigation of active rectifier efficiency was performed depending on the relation between linear and non-linear load currents of the grid node, as well as on active power load of the active rectifier. Efficiency analysis was based on the developed computer model of the grid node with connected non-linear load simultaneously with the variable frequency drive with active rectifier.
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Date submitted2015-08-13
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Date accepted2015-10-29
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Date published2016-04-22
Multicriteria estimation of bearing capacity of geomaterials
- Authors:
- I. A. Brigadnov
In the article the problem of an estimation of bearing capacity of geomaterials as a deform-able solid is considered in the current configuration, which may be as the reference (undeformed) or the actual (deformed). We propose an original variational approach to the problem for stresses in selected subdomains, in which, depending on different engineering considerations, average in-tegral values of different component of stresses are estimated and from their aggregate the bearing capacity of the current configuration of the solid is estimated regarding to given external influ-ences. In each of the selected subdomain the weakest stress field is obtained which is globally bal-anced with external influences. For example, the assessment of the average integral hydrostatic pressure is needed for study of bearing capacity of geomaterials.
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Date submitted2009-10-21
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Date accepted2009-12-16
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Date published2010-09-22
Geomechanical foundations of the safe extraction in joint mining of rich, coppery and ore patches in deep ore mines at Тalnakh
- Authors:
- V. A. Zvezdkin
- A. A. Andreev
The paper deals with the specific formation of stress fields in ore-bearing intrusions at the Oktiabrsky and Talnakh ore deposits with due account of depth of occurrence and formation of tectonic disturbances. The authors have investigated the influence of mining works on stress state of ore-bearing portion of the intrusion. The relationships were obtained in terms of the formation of stress fields in the intrusion during its undermining, overmining and joint mining of several ore deposits. Some recommendations are given for mining of series of ore formations at the Oktiabrsky and Talnakh deposits.
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Date submitted2009-10-29
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Date accepted2009-12-26
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Date published2010-09-22
Control system of rock pressure at the «Antey» deposit
- Authors:
- B. A. Prosekin
- E. A. Ilin
The paper deals with the geomechanical monitoring system of the Antey deposits of uranium ores. Characteristics of the methods and means for rock pressure control are given.
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Date submitted2009-10-14
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Date accepted2009-12-11
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Date published2010-09-22
Investigation of present-day stress-strain state of rock mass by the results of observations at geodynamic polygons
- Authors:
- S. N. Savchenko
- E. V. Kasparyan
- Yu. G. Smagina
The methods are suggested for treatment of the results of optical distance and levelling measurements at the underground geodynamic polygons involving in their calculation the tensors of additional stresses and deformations, component of rotation and specific energy of deformability. As an example, consideration is given to changes in time of movements, deformations and specific energy of deformability at one of geodynamic polygons of the Kola peninsular.
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Date submitted2009-10-18
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Date accepted2009-12-09
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Date published2010-09-22
Influence of blocky-hierarchy structure of geological medium on the forming of natural and technogenic geodynamic fields in the North-West part of the Amur geoblock
- Authors:
- I. Yu. Rasskazov
- B. G. Saksin
On the example of the South-Argun uranium ore district of Zabaikalie consideration is given to the interaction of regional and local fields of stresses. The district includes a number of deposits prone to rock bursts. The performed analysis contains data on recent geodynamics of the explored part of the Amur geoblock as well as on geomechanical and geologo-structural materials of Tulukuev caldera and of Antey deposit. It is shown that with the use of the M.A. Sadovsky relationship the indices of local structural forms of a row are subjected to unified laws of deformation and fracturing. Conclusion was made that at the beginning of deposit exploitation the direction of action of stress field within rock mass conformed to regional one, and then it considerably changed under influence of large-scale mining operations.
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Date submitted2009-07-25
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Date accepted2009-09-09
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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.
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Date submitted2009-07-12
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Date accepted2009-09-16
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Date published2010-04-22
Numerical assessment of stress-strain field in vicinity of large open pit mine taking into account geomechanical, geological and mining factors
The results of modeling of rock mass stress state in the vicinity of large open pit mine using finite-elements method are represented. The model allows to take into account the influence of large-scale fractures. The initiation of boundary conditions is based on the results of determination of stress parameters in situ. The locations of risk areas near the slope are defined.