Purpose. Finding dependence between reliability indexes and power quality. Working out methodology for calculation of reliability index reduction depending on poor power quality based on found dependency. Methodology. The method of harmonic analysis, the principle of superposition for instantaneous power and the methods of the theory of electric machines. The research objects are distribution processes, processes of transformation, transmitting and consumption of electrical energy in power systems of 6 and 0.4 kV with non-sinusoidal voltage in it. The subjects of the research are reliability indexes of separate power supply system units and its dependency of indexes of electromagnetic compatibility. Findings. Scientific explanation of equipment reliability index reduction depending on poor power quality in power system. Detection of the effect of non-sinusoidal voltage on the reliability of transformers and cable lines. Originality. The article analyzes the problems of electricity quality at the moment and describes the importance of solving these problems. The solutions are mainly based on the change in the level of harmonics affecting the power grids, thus improving the quality of electricity. In the work, the analysis of non-sinusoidal voltage influence on power system units reliability indexes is conducted based on typical city power supply scheme. Practical value. Finding of regularities of electromagnetic processes flaws in power system units of 6 and 0.4 kV depending on non-sinusoidal voltage level. Based on researched regularities, the process of reliability index change should be described depending on power quality. The research is conducted for such power system elements as transformers and cable lines. Based on the research, the characteristics of power system units reliability index change are built depending on the load level.
InforMAtIon technoloGIes In MoDelInG operAtIon MoDes of MInInG DewAterInG plAnt BAseD on econoMIc AnD MAtheMAtIcAl AnAlysIs purpose. To ensure the energy efficiency of coal mine power systems. This can be achieved by using rational modes of a sump plant under multifactor initial conditions. Methodology. The research technique is based on the theory of economic and mathematical analysis and the general theory of electrical engineering. findings. For the first time we suggested using the criterion for maximizing the mathematical expectation of the integral (total) profit (savings) P Σ (Y). The foregoing allows us to select an economically feasible diameter for the discharge pipelines of mine drainage plants. The value of the economically feasible diameter (when using this criterion) is greater than when using the crite rion of minimizing the production function P (Y). Therefore, it is possible to achieve maximum economic efficiency. Using reserve pipelines allows the value of the production function P (Y) to be decreased and the value of the integral (total) profit P Σ (Y) to be increased. For the first time, it has been noted that when using various criteria to determine the economically advantageous diam eters of the main pipelines of a mine drainage plant, the value of the economically advantageous diameter does not depend on the number of reserve pipelines used. originality. The research presents the theoretical substantiation of the feasibility of using economic and mathematical analysis in the search for optimal operating modes of drainage plants. We established the dependencies between the parameters of the drainage unit and the indicators of economic efficiency. This allows us to optimize the electromechanical system for energy con sumption. We proposed a method for selecting the number and diameter of pressure pipelines of a mine drainage plant, taking into account a set of technological parameters that provide maximum profit. practical value. We selected and justified the search criteria for the optimal mode of the electromechanical mine drainage. We also developed an algorithm and software package for determining the rational diameter and number of pipelines. Mathematical dependencies make it possible to optimize the operation of a drainage plant according to two criteria, which, taking into account 20 % of the electrical consumption by a drainage system in the mine's energy balance, creates additional opportunities for increas ing the energy efficiency of mining enterprises.
Purpose. To substantiate a technique of a choice of nominal power of power transformers for increase of their use efficiency in distributive electric networks of the cities Methods. Analytical processing of statistical data. Findings. The paper solves the problem of efficient use of the installed power of transformers, their rational choice in the design of urban electrical networks. It was found that the choice of transformers according to classical methods causes a significant error and an overestimation of the rated power at the design stage. The method of reducing this error was developed for selecting the power of transformers of urban electrical networks. This method takes into account the predicted indicators of the operating modes of the equipment, the type of consumers, the load capacity of the equipment, the parameters of the operating mode and the environment, constant heating time of existing types of transformers that can be accepted for installation, the appropriate level of reactive load compensation. Originality The scientific novelty lies in the development of the method for selecting the rated power of power transformers 6 (20) /0.4 kV urban distribution networks by comprehensive consideration of the parameters of typical consumers and their actual structure, which will effectively use transformer equipment for load capacity during the regulated period of their operation. Practical value. The obtained results show the increase in the efficiency of capital and operating costs by selecting a rational rated power of distribution transformers 6 (20) / 0.4 kV with ensuring the effective use of their load capacity in the conditions of electric grids of cities.
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