2022 № 5 Електротехніка і Електромеханіка
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Документ Method for assessing unevenness of cellulose insulation layers aging of power transformers winding(Національний технічний університет "Харківський політехнічний інститут", 2022) Poliakov, M. O.; Vasylevskyi, V. V.Improving the methods of estimating the insulation aging of the oil-immersed power transformer windings is an urgent task for transformer condition monitoring systems. The scientific novelty of the work is to take into account the uneven distribution of temperature and humidity along the vertical axis of the winding in modeling the aging of insulation and to develop methods for determining the conditions under which the aging rate of insulation in the intermediate layer will exceed aging rate in the hottest layer. The purpose of the work is to evaluate the wear unevenness of cellulose insulation based on modeling the distribution of temperature and humidity along the vertical axis of the power transformer winding. Methods. The transformer winding is mentally divided into horizontal layers of equal height, the reduction of service life is calculated in parallel for all horizontal layers. Layer with the maximum degree of aging for the entire period of operation and storage of the transformer is recognized as determining the reduction in the service life of the insulation of the transformer as a whole. A model of the interaction of winding layers is developed, with determination of temperatures, humidity, relative rate of aging of each layer due to temperature and humidity as a function of traditional design parameters such as load, cooling temperature, heat capacity and thermal resistance of transformer. The index of exceeding the aging rate by the layered method in comparison with this rate for the hottest layer is offered. The method of genetic algorithms determines the conditions for obtaining the maximum value of this index. Results. A computer model has been developed to predict the aging of the cellulose insulation of transformer windings. According to the proposed method, a layer with significantly shorter insulation aging time (in the example, time reduced by 39.18 %) than for the upper layer was determined, which confirms the feasibility of layer-by-layer monitoring and modeling of insulation aging processes of power oil-immersed transformer windings.Документ Approximate method for calculating the magnetic field of 330-750 kV high-voltage power line in maintenance area under voltage(Національний технічний університет "Харківський політехнічний інститут", 2022) Rozov, V. Yu.; Reutskyi, S. Yu.; Pelevin, D. Ye.; Kundius, K. D.In order to organize effective protection of working personnel from the action of strong electromagnetic influence when performing work on live high-voltage power lines (HVPL), the existing methods of calculating the magnetic field (MF) need to be developed in the direction of their simplification during operational use. Goal. The purpose of the work is to develop an approximate method and a simplified methodology for calculating the magnetic field flux density near the surface of the 330-750 kV HVPL wires for the prompt determination of the safe distance of the working personnel to the surface of the HVPL wires at the current value of their operating current. Methodology. A new approximate method of calculating the flux density of the MF in the area of work on live HVPL based on the Biot-Savart law and determining the maximum values of the flux density of the MF on the axes of symmetry N of the suspension of N wires, which are decisive for the protection of working personnel, is proposed. Results. Exceeding the maximum acceptable level of the MF for individual power lines at their nominal currents, adopted in the European Union, and the need to implement measures to reduce MF were revealed. Originality. It is shown that the distribution of the 330-750 kV HVPL near N of its split wires with an error of no more than 2.5 % can be determined by the current of only one of the phases of the HVPL. This distribution of MF, which is uneven, is determined by the order of axial symmetry N with the maximum values of the flux density of the MF lying on the axes of symmetry N of the suspension of the phase wires. Practical value. The development of an approximate method and a simplified methodology for calculating the flux density of the MF near the surface of the wires of 330-750 kV HVPL, which allows you to quickly, without the use of a computer, calculate the safe distance to the wires of a specific HVPL at the current value of its operating current, as well as determine the necessary measures for the protection of personnel from the MF, which can be implemented either by physically limiting the minimum distance from the worker's body to the surface of the wires to a dangerous one, or by necessary reduction of the HVPL operating current during repair work. Verification. An experimental verification of the proposed method and methodology was carried out on a laboratory installation with a mock-up of a phase of a 330 kV HVPL from AC 400 type wires at 1500 A current, which confirmed the correctness of the proposed calculation relationships.Документ Development and validation of enhanced fuzzy logic controller and boost converter topologies for a single phase grid system(Національний технічний університет "Харківський політехнічний інститут", 2022) Muthubalaji, Sankaramoorthy; Devadasu, Ghanta; Srinivasan, Sundararajan; Soundiraraj, NallasamySolar photovoltaic system is one of the most essential and demanding renewable energy source in the current days, due to the benefits of high efficiency, reduced cost, no pollution, and environment friendly characteristics. Here, the maximum power point tracking controller has been implemented for obtaining an extreme power from the photovoltaic array. For this purpose, there are different controller and converter strategies have been deployed in the conventional works. It includes perturb and observation, incremental conductance, fuzzy logic systems, and hill climbing, and these techniques intend to extract the high amount of power from the solar systems under different climatic conditions. Still, it limits with the issues like increased design complexity, high cost consumption, high harmonics, and increased time consumption. The goal of this work is to deploy an improved controlling and converter topologies to regulate the output voltage and power fed to the single phase grid systems. The novelty of the work aims to develop an enhanced fuzzy logic controller based maximum power point tracking mechanism with the boost DC-DC converter topology for a single phase grid tied photovoltaic systems. Practical value. Also, the higher order harmonics suppression and unbalanced current elimination are handled by the use of LCL filtering technique, which efficiently reduces the harmonics in the output of inverter voltage and current. Moreover, it helps to obtain the reduced total harmonics distortion value with improved accuracy and efficiency. Results. There are different performance indicators have been evaluated for validating the proposed enhanced fuzzy logic controller–maximum power point tracking controlling technique. Moreover, the obtained results are compared with some of the conventional controlling algorithms for proving the betterment of the proposed work.Документ Diagnosis and localization of fault for a neutral point clamped inverter in wind energy conversion system using artificial neural network technique(Національний технічний університет "Харківський політехнічний інститут", 2022) Abid, Mimouna; Laribi, Souad; Larbi, M'hamed; Allaoui, TayebTo attain high efficiency and reliability in the field of clean energy conversion, power electronics play a significant role in a wide range of applications. More effort is being made to increase the dependability of power electronics systems. Purpose. In order to avoid any undesirable effects or disturbances that negatively affect the continuity of service in the field of energy production, this research provides a fault detection technique for insulated-gate bipolar transistor open-circuit faults in a three-level diode-clamped inverter of a wind energy conversion system predicated on a doubly-fed induction generator. The novelty of the suggested work ensures the regulation of power exchanged between the system and the grid without faults, advanced intelligence approaches based on a multilayer artificial neural network are used to discover and locate this type of defect; the database is based on the module and phase angle of three-phase stator currents of induction generators. The proposed methods are designed for the detection of one or two open-circuit faults in the power switches of the side converter of a doubly-fed induction generator in a wind energy conversion system. Methods. In the proposed detection method, only the three-phase stator current module and phase angle are used to identify the faulty switch. The primary goal of this fault diagnosis system is to effectively detect and locate failures in one or even more neutral point clamped inverter switches. Practical value. The performance of the controllers is evaluated under different operating conditions of the power system, and the reliability, feasibility, and effectiveness of the proposed fault detection have been verified under various open-switch fault conditions. The diagnostic approach is also robust to transient conditions posed by changes in load and speed. The proposed diagnostic technique's performance and effectiveness are both proven by simulation in the SimPower /Simulink® MATLAB environment.Документ Sensors placement for the faults detection and isolation based on bridge linked configuration of photovoltaic array(Національний технічний університет "Харківський політехнічний інститут", 2022) Latreche, Samia; Khenfer, Amar; Khemliche, MabroukThe photovoltaic market has been increased over the last decade at a remarkable pace even during difficult economic times. Photovoltaic energy production becomes widely used because of its advantages as a renewable and clean energy source. It is ecofriendly, inexhaustible, easy to install, and the manufacturing time is relatively short. Photovoltaic modules have a theoretical lifespan of approximately 20 years. In real-life and for several reasons, some photovoltaic modules start to fail after being used for a period of 8 to 10 years. Therefore, to ensure safe and reliable operation of photovoltaic power plants in a timely manner, a monitoring system must be established in order to detect, isolate and resolve faults. The novelty of the proposed work consists in the development of a new model of sensors placement for faults detection in a photovoltaic system. The fault can be detected accurately after the analysis of changes in measured quantities. Purpose. Analysis of the possibility of the number and the position of the sensors into the strings in function of different faults. Methods. This new method is adapted to the bridge linked configuration. It can detect and locate failure points quickly and accurately by comparing the measured values. Results. The feasibility of the chosen model is proven by the simulation results under MATLAB/Simulink environment for several types of faults such as short-circuit current, open circuit voltage in the photovoltaic modules, partially and completely shaded cell and module.Документ Single phase transformerless inverter for grid connected photovoltaic system with reduced leakage current(Національний технічний університет "Харківський політехнічний інститут", 2022) Janardhan, Gurram; Surendra Babu, N. N. V.; Srinivas, G. N.Transformerless inverters are of vital importance in the field of grid connected solar photovoltaic systems offering higher efficiency than the conventional one. i.e., using transformer. General grid connected inverters are constituting of transformers requires more area besides the loss in them. Problem. Eliminating transformers can cause leakage current due to the variation of common mode voltage which in turn due to parasitic capacitance effect. Research literature in transformerless inverters has addressed the problems of common mode leakage current issues by offering the study of different inverter topologies like H4, H5, H6 and HERIC etc. utilizing variety of modulation strategies like unipolar, bipolar pulse width modulations. Goal. The paper significantly presents a new transformerless inverter topology, analyzes common mode voltage and leakage current behavior of the system. The simulation is carried out for comparing the leakage current profiles with other transformerless inverter topologies in literature. Novelty. This paper gives an impression of the efficient transformerless inverter for grid connected photovoltaic system. Results. The various inverter topologies full bridge with different pulse width modulation techniques are analyzed and to determine the common mode voltages and leakage currents.Документ Direct torque control based on second order sliding mode controller for three-level inverterfed permanent magnet synchronous motor: comparative study(Національний технічний університет "Харківський політехнічний інститут", 2022) Guezi, Abderrahmane ; Bendaikha, Abdelmalik; Dendouga, AbdelhakimThe permanent magnet synchronous motor (PMSM) has occupied a large area in the industry because of various benefits such as its simple structure, reduced moment of inertia, and quick dynamic response. Several control techniques have been introduced for the control of the PMSM. The direct torque control strategy associated to three-level clamped neutral point inverter has been proven its effectiveness to solve problems of ripples in both electromagnetic torque and stator flux with regard to its significant advantages in terms of fast torque response. Purpose. The use of a proportional integral speed controller in the direct torque control model results in a loss of decoupling with regard to parameter fluctuations (such as a change in stator resistance value induced by an increase in motor temperature), which is a significant drawback for this method at high running speeds. Methods. That is way a second order sliding mode controller based on the super twisting algorithm (STA) was implemented instead of PI controller to achieve a decoupled control with higher performance and to insure stability while dealing with parameter changes and external disturbances. Results. The simulation results carried out using MATLAB/Simulink software show that the model of direct torque control based on a three-level inverter-fed permanent magnet synchronous motor drive has better performance with second order sliding mode speed controller than the proportional integral controller. Through the response characteristics we see greater performance in terms of response time and reference tracking without overshoots. Decoupling, stability, and convergence toward equilibrium are all guaranteed.Документ Solar flat plate collector enhanced by two reflectors: optimum tilts of reflectors(Національний технічний університет "Харківський політехнічний інститут", 2022) Rachedi, Mohamed Yacine; Bechki, Djamel ; Marif, Yacine; Bouguetaia, HamzaIn some solar concentrating system applications, in which the incoming sunlight is augmented by using commercial flat plate reflectors placed on different sides of the planar collector, it is very important to choose the optimum tilts of boosters (attached edge-to-edge on the top and bottom sides of the solar collector) for each month, to enhance their received solar irradiation over the year in the southern Algeria. The novelty of the proposed work consists of the development of a novel mathematical model in which the reference of the reflector’s tilt angles is the collector plane, and optimal tilts are optimized on the average day of each month. Purpose. This paper proposes a novel analytical model of two identical planer reflectors, placed on the top and bottom of a latitude tilted flat plate solar collector, for optimizing their optimal inclination angles during the daytime throughout the year in Ouargla city, southeast of Algeria. Methods. Optimal tilt angles of reflectors were obtained by searching for the optimum captured solar irradiation on the collector’s surface from each reflector in the representative day of each month of the year. After that, the obtained tilts were used for calculating incoming solar irradiation on the received area and comparing them to the solar collector without reflectors. Results. The findings of this paper showed that the reflector’s inclination angles were variable from one month to another in which the upper reflector’s tilts reached its maximum in June and minimum in December, contrarily for the lower reflector. Again, an increase of 28.05 % in the daily received solar irradiation on the collector surface with reflectors compared to the conventional one.Документ Impact of fractional filter in PI control loop applied to induction motor speed drive(Національний технічний університет "Харківський політехнічний інститут", 2022) Hassainia, Saida ; Ladaci, Samir; Kechida, Sihem; Khelil, KhaledOne of the main problems of electrical machine control systems is to obtain a satisfactory performance in the rejection of load disturbances, as well as in the set-point tracking tasks. Generally, the development of control algorithms does not take into account the presence of noise. Appropriate filtering is, therefore, essential to reduce the impact of noise on the output of the controller, in addition to the machine output. Recently, there has been a great tendency toward using fractional calculus to solve engineering problems. The filtering is one of the fields in which fractional calculus has received great attention. The importance of filters in signal processing and other engineering areas is unquestionable Novelty. The proposed work is intended to be a contribution in the recent works conducted on the influence of the fractional filtering on the control robustness of induction machines control. Purpose. The main contribution of this research is the application of fractional filtering to the standard PI control loop for an induction motor speed drive. Methods. In order to assess its impact and benefit, different structures for introducing the filters are investigated, A first order filter is considered in different positions, whether before or after the controller or even in both positions at the same time, with a noise source. A review of the index performance evolution (the Integral Square Error, Integral Absolute Error and Integral Time Absolute Error) has allowed a configuration design of the filter. Results. Intensive simulations were performed with a control setup using integer and fractional order filters, which permitted to conclude that the fractional filters give better performance indices compared to the integer one and thus improve the dynamic characteristics of the system.Документ The method of multi objective synthesis of stochastic robust control by multimass electromechanical systems under non-gausian random external disturbances(Національний технічний університет "Харківський політехнічний інститут", 2022) Kuznetsov, B. I.; Nikitina, T. B.; Bovdui, I. V.; Voloshko, O. V.; Kolomiets, V. V.; Kobylianskyi, B. B.Development of the method of multi objective synthesis of stochastic robust control by multimass electromechanical systems to satisfy various requirements for the operation of such systems in various modes under non-gausian random external disturbances. Methodology. The problem of multi objective synthesis of stochastic robust control by multimass electromechanical systems to satisfy various requirements for the operation of such systems in various modes under non-gausian random external disturbances solved based on the choosing of weight matrices in the robust control goal vector.The calculation of the target vector is performed based on the solution of the zero-sum vector antagonistic game. The components of the game payoff vector are variable quality indicators that are applied to the system operation in various modes. The calculation of the components of payoff vector game are performed based on the simulation of the initial system closed by the synthesized stochastic controllers in various operating modes and under various external influences and variations in the parameters of the uncertainty of the initial plant. Results. The results of multi objective synthesis of stochastic robust twomass electromechanical servo systems modes under non-gausian random external disturbances in which differences requirements for the operation of such systems in various modes were satisfied are given. Based on the results of modeling and experimental studies it is established, that with the help of synthesized robust nonlinear controllers, it is possible to improve of quality indicators of two-mass electromechanical servo system in comparison with the system with standard regulators. Originality. For the first time the method of multi objective synthesis of stochastic robust control by multimass electromechanical systems to satisfy various requirements for the operation of multimass systems in various modes is developed. Practical value. From the point of view of the practical implementation the possibility of solving the problem of multi objective synthesis of stochastic robust control systems to satisfy various requirements for the operation of multimass electromechanical systems in various modes is shown.Документ Development and study of a microprocessor automatic control system for a mono-switch tie type with a linear inductive electric motor and a discrete speed controller(Національний технічний університет "Харківський політехнічний інститут", 2022) Buriakovskyi, S. G.; Asmolova, L. V.; Maslii, An. S.; Maslii, Ar. S.; Obruch, I. V.The article is devoted to the development of the microprocessor automatic control system for a gearless controlled electric drive of a mono-switch tie based on a linear inductor electric motor. This solution provides control the position of the switch point, to carry out the transfer process with a smooth drive of shanks to the frame rail, to protect electric motor elements from overloads. Goal. Development and study of the behavior of microprocessor automatic control system for mono-switch tie type with linear inductive electric motor and discrete PID speed controller which coefficients are adjusted according to Chien-Hrones-Reswick method to meet modern traffic safety requirements and improve operational reliability factors. Methodology. On the basis of electric drive theory, a kinematic line of a mono-switch tie type with nonlinear friction characteristic is presented. Using differential equation theory and Laplace transformation, a mathematic description of a linear inductor electric motor has been made. Using the z-transform method, a difference equation for describing a discrete PID speed controller is obtained, the coefficients of which are derived using the Chien-Hrones-Reswick method. A simulation mathematical model of the electric drive mono-switch tie type as the microprocessor automatic control system with linear inductive electric motor and discrete PID speed controller and nonlinear friction characteristic was built in MATLAB. Results. Simulation modelling of a mathematical model of the microprocessor automatic control system of the electric drive mono-switch tie type with the linear inductive electric motor and discrete PID speed controller and nonlinear friction characteristic have been developed and performed. Studies of dynamics of switch point movement have shown that, a drive time of less than 0.7 s at a constant speed motor armature of 0.2 and 0.3 m/s provides to meet modern requirements for railway switch points. The application of discrete PID speed controller has shown improved dynamics of switch point. Originality. First for the electric drive of the mono-switch tie type with linear inductive electric motor a mathematical model of the discrete PID speed controller and nonlinear friction characteristic as an object of speed control of switch point movement, has been developed. Practical value. Mathematical model of a railway track switch of the mono-switch tie type with linear inductive electric motor and discrete PID speed controller has been developed to carry out the control of the position of the switch point, process with a smooth drive them to the frame rail, to protect electric motor elements from overloads.Документ Design of single switch-boosted voltage current suppressor converter for uninterrupted power supply using green resources integration(Національний технічний університет "Харківський політехнічний інститут", 2022) Chandramouli, Bethi; Vijayaprabhu, Arumugam; Arun Prasad, Deenadayalan; Kathiravan, Kannan; Udhayaraj, Natarajan; Vijayasanthi, MaineniUninterrupted power supply is the major requirement in the areas since it involves human lives. In the current scenario the demand and price of fossil fuels is increasing rapidly and availability also is not sufficient to the needs, an alternative identification to power generation is solar and wind energies. The purpose of designing an aimed, single switch boosted voltage and current suppressor (SS-BVCS) converter topology that interfaces both the wind and solar hybrid model. The method involves in the proposed chopper converter is derived by simply merging a switch and a pair of diodes and CLC filter which is used in realization of zero voltage switching for the main switch and a reversing diode to extract high voltage gain. The designed SS-BVCS converter topology can able to have a tight self-control on two power-processing paths. The novelty of the SS-BVCS converter module is designed to ensure maximum throughput, feeding to the load with high quality uninterrupted output, by boosting the DC voltage to a required amount and thereby supressing the current. Practical value obtained by the developed model utilizes both the sources for supply to the load individually or combined based on the extraction availability of the feeder. Also, the proposed SS-BVCS module delivers with efficient lesser component count and gaining maximum power from the harvest of green energy.