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Date submitted2024-04-11
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Date accepted2024-11-07
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Date published2025-01-17
Thyristor booster device for voltage fluctuation reduction in power supply systems of ore mining enterprises
The article is devoted to solving the problem of voltage fluctuations in the power supply systems of ore mining enterprises. The connection of high-power consumers with abruptly variable operating mode (for example, high-voltage mining excavators) causes voltage fluctuations and sags, disabling electrical equipment, communication, and automation devices in the 6-10 kV distribution network, which disrupts technological processes, etc. The use of existing solutions and methods to reduce voltage variations caused by dynamic loads is not effective. To solve the problem, booster transformers with high-speed thyristor switches can be used to work out switching the control steps towards increasing or decreasing the voltage. The authors offer a new circuitry solution for a thyristor booster device (TBD) with a pulse-phase control method. The purpose of the research is to determine the control laws of TBD, which enable to effectively reduce voltage fluctuations from dynamic load in the power supply systems of mining enterprises. The article provides a schematic diagram of the TBD and describes the principle of operation of the device. Some modes of increasing and decreasing the output voltage of the TBD, as well as the basic mode (without voltage addition) are provided. Mathematical modeling of TBD control processes was carried out and adjustment characteristics were set taking into account the load power factor. On a simulation computer model of a 6 kV electric network with a dynamic load, the verification of the adjustment characteristics of TBD obtained during mathematical modeling was carried out. Based on the research results, the laws for regulating the output voltage of TBD were established. The TBD effective control range with normal permissible limits of odd harmonics have been determined. The conducted research will make it possible to implement the device control system.
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Date submitted2022-10-26
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Date accepted2023-02-13
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Date published2023-07-19
Determination of the grid impedance in power consumption modes with harmonics
The paper investigates the harmonic impedance determination of the power supply system of a mining enterprise. This parameter is important when calculating modes with voltage distortions, since the determined parameters of harmonic currents and voltages significantly depend on its value, which allow the most accurate modeling of processes in the presence of distortions in voltage and current. The power supply system of subsurface mining is considered, which is characterized by a significant branching of the electrical network and the presence of powerful nonlinear loads leading to a decrease in the power quality at a production site. The modernization of the mining process, the integration of automated electrical drive systems, renewable energy sources, energy-saving technologies lead to an increase in the energy efficiency of production, but also to a decrease in the power quality, in particular, to an increase in the level of voltage harmonics. The problem of determining the grid harmonic impedance is solved in order to improve the quality of design and operation of power supply systems for mining enterprises, taking into account the peculiarities of their workload in the extraction of solid minerals by underground method. The paper considers the possibility of determining the grid impedance based on the measurement of non-characteristic harmonics generated by a special nonlinear load. A thyristor power controller based on phase regulation of the output voltage is considered as such a load. Simulation computer modeling and experimental studies on a laboratory test bench are used to confirm the proposed method. The recommendations for selecting load parameters and measuring device connection nodes have been developed.
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Date submitted2021-11-17
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Date accepted2022-04-06
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Date published2022-11-10
Method for predicting the stress state of the lining of underground structures of quasi-rectangular and arched forms
- Authors:
- Maksim A. Karasev
- Tien Tai Nguyen
A method for predicting the stress-strain state of the lining of underground structures, the shape of the cross-section of which is different from the circular outline, is considered. The main task of the study is to develop a methodology for assessing the influence of the parameters of the cross-section shape of underground structures on the stress state of the lining. To solve this problem, a method for calculating the stress state of the lining for arched tunnels with a reverse arch and quasi-rectangular forms is substantiated and developed. The methodology was tested, which showed that the accuracy of the prediction of the stress state of the lining is sufficient to perform practical calculations. An algorithm for multivariate analysis of the influence of the cross-sectional shape of underground structures of arched and quasi-rectangular shapes on the stress state of the lining is proposed. Parametric calculations were performed using the developed algorithm and regularities of the formation of the stress state of the lining of underground structures for various engineering and geological conditions, as well as the initial stress state field, were obtained. A quantitative assessment of the influence of geometric parameters of tunnels on their stress-strain state was performed.
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Date submitted2021-01-20
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Date accepted2021-03-15
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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.
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Date submitted2020-06-02
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Date accepted2020-12-15
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Date published2020-12-29
Method for calculating dynamic loads and energy consumption of a sucker rod installation with an automatic balancing system
The efficiency of sucker rod pump installations, which have become widespread in mechanized lift practice, is largely determined by the balance of the drive. During the operation of sucker rod installations, the balance of loads acting on the rod string and the drive can change significantly due to changes in the dynamic fluid level, which leads to a decrease in balance and an increase in loads on the pumping equipment units. The increase and decrease in the dynamic level in accordance with the pumping and accumulation cycle occurs in wells operating in the periodic pumping mode. It is shown that during the operation of equipment in a periodic mode, fluctuations in the dynamic level and, accordingly, in the loads acting on the nodes occur. This leads to the need for dynamic adjustment of the balancing weights to ensure the balance of the pumping unit. A system for automatic balancing of the rod drive has been developed, including a balancing counterweight, an electric motor that moves the load along the balance beam, a propeller and a computing unit. To study the effectiveness of the proposed device, a complex mathematical model of the joint operation of the reservoir - well - sucker rod pump - rod string – pumping unit has been developed. It is shown that due to the dynamic adjustment of the balance counterweight position, the automatic balancing system makes it possible to significantly reduce the amplitude value of the torque on the crank shaft (in comparison with the traditional rod installation) and provide a more uniform load of the electric motor. Equalization of torque and motor load reduces the power consumption of the unit.
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Date submitted2019-11-04
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Date accepted2020-01-12
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Date published2020-10-08
PDC cutter pressure on plastic-brittle rock in the process of its destruction
- Authors:
- Oleg B. Trushkin
- Hamzja I. Akchurin
Presently, there are no methods for calculating the parameters of the drilling practices with rock-cutting tools equipped with polycrystalline diamond composite (PDC cutters). To create such a method requires the studying their work. The article presents the results of bench studies of the PDC cutters in the process of a rock sample breakdown when reproducing the actual layout of the cutters on the working surface of the bit. An important parameter of PDC cutters operation, which is necessary for the bit load analysis, is the pressure of the cutters on the rock during its breakdown. The total pressure of a cutter on the rock can be broken into two mutually perpendicular components: the forcing pressure and the cutting pressure. It is proposed to evaluate the PDC cutters loading at breakage of rocks of different hardness using relative values of forcing and cutting pressures, which are calculated relative to the yield strength of the rock by the die. It is established that the variability of the average relative pressures of forcing and cutting is significantly influenced by drifting per bit turnover and the radius of the cutter on the bit. The dependences of the maximum relative pressures of PDC cutters at the plastic-brittle rock breakdown on the drifting per bit turnover and the radius of the cutter location on the bit are obtained. It has been established that when drifting up to 0.4 mm per turn, the main mechanism of breakdown is cutting, and with the increase of the breakdown depth, the process of forcing becomes decisive.
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Date submitted2018-12-25
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Date accepted2019-03-02
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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.
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Date submitted2010-07-29
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Date accepted2010-09-27
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Date published2011-03-21
Efficiency increasing of condenser batteries operation in mining enterprise`s electric circuits
- Authors:
- A. N. Skamin
This work contains the method of effective reactive power compensation at the expense of high harmonics reduction. The decrease of condenser batteries overloading from the high harmonics is based on variation of condenser power depending on current and voltage spectral structure, electric network parameters and load power.
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Date submitted2010-07-10
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Date accepted2010-09-15
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Date published2011-03-21
Reduction methods of high harmonics influence on the electric equipment operation
- Authors:
- Ya. E. Shklyarsky
- A. N. Skamin
This work contains brief analysis of high harmonics reduction methods. It is offered to make a choice between reduction methods of high harmonics influence on condenser batteries depending on factors of harmonics occurrence. Definition algorithm for the most effective method of high harmonics reduction on condenser batteries operation is created.
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Date submitted2010-07-20
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Date accepted2010-09-01
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Date published2011-03-21
Experimental and theoretical studies and justification of geotechnology of stock pile formation from pelletized gold-bearing ores in order to enhance its filtration properties
- Authors:
- S. B. Tataurov
Optimal parameters of geotechnology of stock pile formation from pelletized gold-bearing ores were established basing on experimental and theoretical studies in order to enhance its filtration properties. In particular, exponential dependence was established of permeability coefficient on the stock pile height and the ultimate strength of the pelletized ore, its bulk weight and content of coarse particles +2 mmin combination with sandy-loamy and loamy fine grained soil. Without account of this data loss of gold within the stock pile can increase over 2 or 3 times. Basing on the results obtained application of the combined geothechnology of heap leaching of gold-bearing clayey materials of natural and man-made origin was justified.
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Date submitted2008-10-21
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Date accepted2008-12-12
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Date published2009-12-11
Assessment of stress-strain state of temporary support during constructhion of station tunnels of the metro
- Authors:
- V. A. Maslak
In-situ testing technique of temporary support is given. The values of stress and normal force in arch and sides of steel support are shown. Determination of vertical load magnitude is done. It was determined that vertical load on support decreases by 1,54 times, if lag of support installation from the face is16 m.