PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems

Determination of permissible operating currents in conditions of non-stationary loads and changes in the number of cable channel lines, as well as in emergency modes, is accompanied by certain difficulties due to the large number of influencing factors. The issue of using numerical modeling in the operation and design of cable structures of complex construction is relevant. Purpose: development of a control system for the distribution of electrical energy in the cable channel to improve the efficiency of use and ensure safe operation of power cables. Results: a block diagram of the cable channel current loading control system using a mathematical model is constructed to check the validity of prospective load conditions. The problem of evaluating the thermal modes of cable channel operation under changing loads was studied. A mathematical model of thermodynamic processes in an underground cable channel that includes several cable lines located in pipes and loaded unevenly is constructed. The temperature field of the channel in the initial operating mode is obtained. The perspective mode of operation of the channel in the conditions of laying an additional two-chain line in the backup pipes has been studied. Temperature fields in the channel with additional lines are obtained. Emergency modes of operation of the cable channel that can lead to significant heating of cable lines are investigated. Temperature fields of the channel under emergency operating conditions were obtained. Changes in the temperature of the most heated cable lines in the initial mode were evaluated in order to control not exceeding the maximum permissible values. Practical relevance: the developed control system using a mathematical model can be used in the design and operation of complex cable structures.

The control of the operating modes of the booster pump station (BPS) is traditionally associated with the use of PID controllers. However, the uncertainty of the characteristics of the object, the nonlinearity of the object and the disturbances associated with a continuous change in the oil supply lead to fluctuations in flow and pressure in the pipeline and on the central control center. One of the effective ways to solve this problem is the use of intelligent systems. Continuous change in oil supply, change in the physicochemical composition of oil, ambient temperature, etc. leads to uncertainty in controlling the liquid level in the separator using a PID controller. In this case, it is advisable to use an adaptive fuzzy fluid level controller in the separator Purpose: to develop an adaptive fuzzy regulator of the level of crude oil in the separator. Methods: development of a mathematical model of automatic control of the liquid level in the separator, development of the architecture of a fuzzy controller, the use of sigmoidal membership functions in the adaptive fuzzifier with the correction of membership degrees by the method of sequential training, the use of Sugeno equations in a fuzzy inference block. Results: on the basis of the developed adaptive fuzzy level controller, the accuracy of maintaining the level with existing uncertainties has increased. The developed mathematical model of the separator confirmed the use of fuzzy control to solve the problem. The accuracy of maintaining the level of crude oil in the separator meets the specified requirements. Practical relevance: the research results were used to develop an adaptive fuzzy level controller for controlling the outflow of crude oil from the separator, which eliminated emergency situations when the separator was operated in the mode of variable inflow of crude oil from the rocking chair.

The article discusses the advantages of a hierarchical approach over standard recognition approaches: a decrease in the number of recognized pixels (by discarding image areas that do not carry useful information for the recognition process), and a decrease in the total image processing time. The essence of the hierarchical recognition method is that it adds preprocessing to the image, highlighting regions of interest in the image (ROI), and recognizes only them. To assess the influence of the hierarchical approach, it was decided to create an analytical model, the input parameters of which are the intensity of the appearance of objects in the recognition zone, the size of the object's image and the maximum possible speed of image processing by the system (under heavy load, the system performance decreases). The model calculates the intensity of servicing requests based on the permissible size of the region of interest (ROI), takes into account the possibility of parallelizing the object recognition process at the expense of the released computing resources. The results obtained during the simulation help to analyze the prospects for applying the hierarchical recognition method for each specific system and to perform a preliminary calculation of the average processing time for one request. Purpose: creating an analytical model for calculating parameters of a hierarchical object recognition system. For this, methods from the theory of mass service systems, the theory of teletrafics and statistical analysis were applied. Results: calculation of optimal characteristics of the system (recommended image size for coarse and accurate search) in conditions of a given image size and the time required by the algorithm for processing one pixel. A version of approximate calculation of object recognition time on an image by a hierarchical recognition system is proposed.

In the production of medium and high voltage cables, insulation is most often cross-linked by the peroxide method. This process of crosslinking is technically complex and to obtain high-quality insulation, it is necessary to correctly select and control the technological mode, so there is a problem in the production of selecting parameters such as the temperature of the sections, the speed of movement of the billet. These parameters can be determined empirically or by calculation. Since the experimental path involves a large expenditure of material and time, it is preferable to use the calculated method of determination. Purpose: development of a mathematical model of heat and mass transfer processes in an inclined line of cable insulation vulcanization. The definition of rational modes of operation of the equipment. Results: an axisymmetric problem of heat and mass transfer in a vulcanization tube is implemented using the finite element method, temperature fields are obtained along the entire length of the vulcanization line, and parameters of the optimal operating mode of the vulcanization line are determined. To solve the problem, a regression expression is used to determine the degree of cross-linking in cross sections and along the length of the insulation coating. The model geometry was implemented using the ANSYS ICEM CFD grid generator, and the calculation was performed by the ANSYS Fluent solver. To confirm the adequacy of the developed model, a full-scale experiment was conducted to determine the maximum temperature in isolation, and a comparison was made with the results of numerical calculation. The convergence of the developed model is evaluated, as well as the adequacy of the model is evaluated by comparing it with similar studies. The study obtained temperature distribution curves on the surface of the core and insulation along the length of the vulcanization line. The influence of such production factors as the insulation rate and the heating mode of the line on the temperature distribution is estimated. Based on the data obtained, the degree of insulation cross-linking was calculated and the optimal technological mode of cross-linking was presented. Practical relevance: the possibility of using the proposed mathematical model to describe vulcanization processes for a wide range of type of medium and high voltage cables, the choice of rational parameters of the vulcanization mode for the designed lines and correction of existing technological modes, which will increase the productivity of the line without losing the quality of manufactured products.

The development of the country's economy is focused on the priority technologies, including those that ensure high energy efficiency of production facilities. The oil production efficiency presupposes a complex consideration of factors affecting the power consumption of oil production facilities, including methods of equipment operation and maintenance, technological modes of operation, various physical, geographical, climatic and other conditions of their functioning. To assess the influence of climatic factors, it is advisable to use mathematical modeling methods that allow to analyze the current data on the facility condition and identify the most critical indicators that should be taken into account when predicting electricity consumption and planning the oil production process. Purpose: formation and testing of a methodology for assessing the influence of climatic factors on the oil production facilities power consumption using the available statistical information on their functioning. Methods: regression analysis of statistical data on the oil fields operation, including data on the power supply system configuration, existing electricity consumers and consumption volumes, operating modes of facilities, as well as data from meteorological services. Results: based on the analysis of the peculiarities of the oil fields operation, a procedure for assessing the influence of climatic factors on its power consumption was proposed. The method is based on the use of regression analysis and formalization of analytical dependences of consumption on various climatic factors, taking into account the detailing of the object structure, changes in its operating modes and seasonality. Recommendations regarding the formation and processing of the initial data for analysis have been formed. Practical testing of the method on the example of an oil field located in the Perm region has been carried out. The procedure for increasing the objectivity of the regression analysis results is described and analytical dependences of power consumption on meteorological factors of temperature, pressure, air humidity and wind speed were obtained. Practical relevance: the method is universal and can be applied at typical facilities, as well as in related industries. The developed analytical dependencies allow taking into account the influence of key climatic factors on the oil production facilities power consumption, which can be an important stage in planning and managing the operating modes of facilities to improve the oil production process economic efficiency.

The issues of rational use, control and saving of energy resources are considered as relevant both at the current moment of time and in the long term. A comprehensive solution to the problems of reducing energy costs and increasing energy efficiency presupposes a competent enterprises energy policy through the construction and development of energy management systems. The basis of such systems is made up of mechanisms for collecting, processing and analyzing data obtained using various information and analytical solutions, monitoring and control means that allow determining key indicators that characterize the production activities efficiency. The presence of a large number of factors associated with a change in the parameters of the electric power system necessitates the use of mathematical modeling methods of power consumption to assess and predict such indicators. Purpose: development of a methodology for calculating the consumption and distribution of electricity based on the matrix-topological method in the power supply system of oil fields using information from existing monitoring systems. Methods: linearization of data in a time series to filter the original array of information. Filtered arrays of information are used as the basis for a combined dataset for matrix-topological calculations. Results: a method and an algorithm for matrix-topological calculation of power consumption of oil production facilities was developed. The method allows to form an initial set of analytical data using a minimum amount of information coming from monitoring systems in the process of oil production, to create a single dataset of an enterprise power supply system using mathematical models of its individual elements, and also to carry out, according to the generated dataset, the calculation of the distribution (consumption) of electrical energy within the entire field using the matrix-topological method. On the basis of the proposed method of matrix-topological calculation, an assessment of electricity consumption was made using the example of the Sukharev field of the company LLC LUKOIL-PERM. Practical relevance: the developed methodology can be used to simulate various production situations, form balance orders, simplify the process of selecting equipment or making decisions.