2023 № 4 Електротехніка і Електромеханіка

Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/67296

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Enhancing power system security using soft computing and machine learning
(Національний технічний університет "Харківський політехнічний інститут", 2023) Venkatesh, Peruthambi; Visali, Nagalamadaka
To guarantee proper operation of the system, the suggested method infers the loss of a single transmission line in order to calculate a contingency rating. Methods. The proposed mathematical model with the machine learning with particle swarm optimization algorithm has been used to observe the stability analysis with and without the unified power flow controller and interline power flow controller, as well as the associated costs. This allows for rapid prediction of the most affected transmission line and the location for compensation. Results. Many contingency conditions, such as the failure of a single transmission line and change in the load, are built into the power system. The single transmission line outage and load fluctuation used to determine the contingency ranking are the primary emphasis of this work. Practical value. In order to set up a safe transmission power system, the suggested stability analysis has been quite helpful.
Theoretical determination of individual values of insulation four-element equivalent circuits elements parameters at technical diagnostics of insulation by absorption methods
(Національний технічний університет "Харківський політехнічний інститут", 2023) Kyrylenko, V. M.; Kyrylenko, K. V.
The aim of this article is to present a methodology of determining of the individual values of the parameters of four-element equivalent circuits for insulation with through conductivity. Methodology. The proposed method consists in the fact that at a time interval of more than 10 s, when the charge indicator no longer contributes to the leakage current, three points t1, t2 and t3 are selected, such that t2 – t1 = t3 – t2. To be able to determine the absorption coefficient R60/R15, it is recommended to take t1 = 15 s, t2 = 37.5 s and t3 = 60 s. At the same time, by subtracting I(t2) – I(t1) and I(t3) – I(t2), the constant component of the absorption curve is excluded and it becomes possible to determine the individual values of the parameters of the generalized equivalent circuit of insulation, additionally using its conductivity in operator form. Results. As calculations show, the correct determination of the parameters of insulation equivalent circuit according to the proposed method is possible only with a certain ratio of these parameters. The charge time of the geometric capacitance Cg(R0+Rd), where R0 and Rd are the resistance that forms the charging exponent, and the resistance of the sensor, should be within 0.2 s
Ensuring standardized parameters for the transmission of digital signals by twisted pairs at the technological stage of manufacturing cables for industrial operating technologies
(Національний технічний університет "Харківський політехнічний інститут", 2023) Bezprozvannych, G. V.; Pushkar, O. A.
In production control and control systems, buildings use many simple devices - sensors to detect light, heat, movement, smoke, humidity and pressure, mechanisms for activation and control of switches, closing devices, alarm, etc. - «operating technologies» (OT). Different communication protocols and field tire technologies, such as Modbus for conditioning systems, Bacnet for access control and Lonworks for lighting, have been traditionally used and used for their connection. Network fragmentation leads to the need to use gateways to transform protocols when creating a single automation system, which complicates the implementation of complex control systems for any object. At the same time, information networks are unified, but the Ethernet protocol used in them for operating technologies for various reasons (technological, cost) has not been widespread. Due to its high bandwidth compared to existing field tire networks, industrial Ethernet is significantly capable of increasing flexibility in the implementation of additional functions in OT. Modern industrial Ethernet networks are based on non-shielded and shielded twisted pair category 5e cables. The presence of additional metal screens in the structure of twisted pair causes the increase in electrical resistance of conductors due to the effect of closeness, the electrical capacity, and the ratio of attenuation in the range of transmission of broadband signals. Purpose. Substantiation of the range of settings of technological equipment to ensure standardized values of the extinction coefficient and immunity based on the analysis of the results of measurements in a wide frequency range of electrical parameters of shielded and unshielded cables for industrial operating technologies. Methodology. Experimental studies have been performed for statistically averaged electrical parameters of the transmission of pairs for 10 and 85 samples of 305 m long and shielded cables of category 5e, respectively. It is determined that in the frequency range from 1 to 10 MHz, unshielded cables have less values of the attenuation coefficient. In the range of more than 30 MHz, the shielded cables have smaller values of the attenuation due to the influence of the alumopolymer tape screen. It is established that the coefficient of paired correlation between asymmetries of resistance and capacity of twisted pairs is 0,9735 - for unshielded and 0,9257 - for shielded cables. The impact has been proven to a greater extent asymmetry of resistance the pairs on the increasing noise immunity of cables. The influence noise interference on the deviation of the diameter and electrical capacity of the isolated conductor from the nominal values in the stochastic technological process is analyzed. The strategy of technological process settings to ensure the attenuation and the noise immunity in the high-frequency range is substantiated. Practical value. Multiplicative interference, caused by random changes in the stochastic technological process, can lead to a deviation of diameter 2 times from the nominal value at level of probability at 50 %. The equipment settings of the technological equipment must guarantee the coefficient of variation capacity of the insulated conductor at 0.3 % for high level of noise immunity.
Numerical-field analysis of active and reactive winding parameters and mechanical characteristics of a squirrel-cage induction motor
(Національний технічний університет "Харківський політехнічний інститут", 2023) Milykh, V. I.
The active and reactive (inductive) winding resistances of three-phase inductions motors (IMs) are investigated. These important parameters are determined during design and are the basis for calculating a number of energy parameters and characteristics. Problem. In the classical design of IM, the winding resistances are determined with insufficient accuracy due to a number of assumptions and conventions. Especially it concerns the operation of IM with increased slip and it affects the accuracy of realization of its design data, starting parameters and characteristics. Goal. The paper aims to further develop the IM design system by numerical-field computational analysis of active and reactive resistances of the IM windings in the whole range of changes in its slip and calculation of the mechanical characteristic of IM to confirm the adequacy of the calculations of these resistances. Methodology. Resistances of the IM windings are determined by numerous calculations of the magnetic fields of dispersion with the FEMM program within stator and rotor teeth steps, and with current displacement in a squirrel-cage rotor core. Everything is done in the slip range when operating from start-up to idle with changing currents in the slots and the corresponding magnetic saturation of the core teeth. A Lua script has been created for the calculations, controlling the FEMM program and providing automation of all calculations. Results. The numerical-field method shows that the classical design method gives very large errors in determining the magnetic conductivities of IM slot dispersion, as well as current displacement in the bars of the squirrel-cage rotor winding. This is especially evident with increased slips in the start-up mode. Originality. Numerical estimates of the differences between the classical and numerical-field methods are given and the origin of errors is analyzed: the strong saturation of the teeth of the stator and rotor cores. This leads to a significant decrease in the magnetic conductivities of slot dispersion and the practical absence of current displacement in the rotor bars, on which the main emphasis was previously made. The obtained results made it possible to calculate the mechanical characteristic of the IM according to a transparent formula without the use of correction coefficients and reference graphical functions. Practical value. The provided technique of numerical-field analysis and the obtained results of the calculation of active and reactive winding resistances and mechanical characteristic are recommended as a basis for the improvement of the IM design system.
Optimization of spatial arrangement of magnetic field sensors of closed loop system of overhead power lines magnetic field active silencing
(Національний технічний університет "Харківський політехнічний інститут", 2023) Kuznetsov, B. I.; Nikitina, T. B.; Bovdui, I. V.; Voloshko, O. V.; Kolomiets, V. V.; Kobylianskyi, B. B.
Development of a method for optimization of spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active silencing canceling of the magnetic field generated by overhead power lines. Methodology. Spatial arrangement and angular position of magnetic field sensors of closed loop system of overhead power lines magnetic field active silencing determined based on binary preference relations of local objective for multi-objective minimax optimization problem, in whith the vector objective function calculated based on Biot–Savart law. The solution of this vector minimax optimization problem calculated based on nonlinear Archimedes algorithm of multi-swarm multi-agent optimization. Results. Results of simulation and experimental research of optimal spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active silencing of the magnetic field generated by overhead power lines with a barrel-type arrangement of wires. Originality. The method for optimization of spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active shielding of the magnetic field generated by overhead power lines is developed. Practical value. An important practical problem optimization of spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active silencing of the magnetic field generated by overhead power lines has been solved.
Model reference adaptive system speed estimator based on type-1 and type-2 fuzzy logic sensorless control of electrical vehicle with electrical differential
(Національний технічний університет "Харківський політехнічний інститут", 2023) Khemis, Abderrahmane; Boutabba, Tarek; Drid, Said
In this paper, a new approach for estimating the speed of in-wheel electric vehicles with two independent rear drives is presented. Currently, the variable-speed induction motor replaces the DC motor drive in a wide range of applications, including electric vehicles where quick dynamic response is required. This is now possible as a result of significant improvements in the dynamic performance of electrical drives brought about by technological advancements and development in the fields of power commutation devices, digital signal processing, and, more recently, intelligent control systems. The system’s reliability and robustness are improved, and the cost, size, and upkeep requirements of the induction motor drive are reduced through control strategies without a speed sensor. Successful uses of the induction motor without a sensor have been made for medium- and high-speed operations. However, low speed instability and instability under various charge perturbation conditions continue to be serious issues in this field of study and have not yet been effectively resolved. Some application such as traction drives and cranes are required to maintain the desired level of torque down to low speed levels with uncertain load torque disturbance conditions. Speed and torque control is more important particularly in motor-in-wheel traction drive train configuration where vehicle wheel rim is directly connected to the motor shaft to control the speed and torque. Novelty of the proposed work is to improve the dynamic performance of conventional controller used of model reference adaptive system speed observer using both type-1 and type-2 fuzzy logic controllers. Purpose. In proposed scheme, the performance of the engine is being controlled, fuzzy logic controller is controlling the estimate rotor speed, and results are then compared using type-1 and type-2. Method. For a two-wheeled motorized electric vehicle, a high-performance sensorless wheel motor drive based on both type-2 and type-1 fuzzy logic controllers of the model reference adaptive control system is developed. Results. Proved that, using fuzzy logic type-2 controller the sensorless speed control of the electrical differential of electric vehicle EV observer, much better results are achieved. Practical value. The main possibility of realizing reliable and efficient electric propulsion systems based on intelligent observers (type-2 fuzzy logic) is demonstrated. The research methodology has been designed to facilitate the future experimental implementation on a digital signal processor.
Voltage regulation using three phase electric spring by fuzzy logic controller
(Національний технічний університет "Харківський політехнічний інститут", 2023) Ikhe, Atul; Pahariya, Yogesh
The renewable energy sources such as solar and wind power have increased significantly in recent years. However, as the generation of renewable energy has become more integrated, its intermission and instability have a major impact on the power system’s stability, such as voltage instability and frequency flicker. Purpose. In order to address the different power quality issues brought on by intermittent and unreliable renewable energy sources, electric spring offers a novel solution. It was proposed as a technique for regulating load and adjusting output power. For the integration of electric springs with noncritical loads, a contemporary control mechanism is described in this paper. Novelty. The suggested work is innovative in that it presents an improved control technique that efficiently maintains voltage stability as voltage changes. Method. The proposed technique is based on an analysis of the initial conditions and input data for developing fuzzy rules for calculating compensating voltages in relation to the difficulties. Results. This suggested fuzzy controller will be able to maintain the regular operation of the electric spring of power output control stability as well as continuing to provide power factor improvement and voltage control for significant loads, including the home’s protection system. Practical value. A detailed study of typical voltage regulation is undertaken, supported by simulation results, to demonstrate the effectiveness of the applied control scheme in cancelling the corresponding issues with power quality.
Experimental study of electromagnetic disturbances in common and differential modes in a circuit based on two DC/DC boost static converter in parallel
(Національний технічний університет "Харківський політехнічний інститут", 2023) Benazza, Baghdadi; Bendaoud, Abdelber; Slimani, Helima; Benaissa, Mohamed; Flitti, Mohamed; Zeghoudi, Abdelhakim
An electronic control and closing control at the switch (MOSFET) will allow a parallel connection of two DC/DC boost converters. The reason for paralleling converters is to increase the efficiency of the power conversion process. This means that the overall power loss on the main switches is half the power loss on the main switch of a converter. It has been proven that DC-DC converters operating in parallel have different dynamics than a single converter. In this paper, the study is based on a system of two boost converters operating in parallel under current mode control. Although two converters operating in parallel increase the efficiency of the system, if the control parameters are not chosen correctly, the system becomes unstable and starts to oscillate. Purpose of this work is to present the analysis of high frequency electromagnetic disturbances caused by the switching of power switches in DC/DC boost static converters mounted in parallel in the presence of cables. We will study the improvement of the electromagnetic compatibility performances which can be brought by the choice of a static converters for industrial use. Methods. For the study of the path of the currents in common mode and in differential mode, it was possible to evaluate experimentally the electromagnetic compatibility impact in common mode and in differential mode of two boost converters connected in parallel in an electric circuit in connection with the source through a printed circuit board of connection between the source and the load, while using the two basic methods, namely the prediction of the conducted electromagnetic interference, the temporal simulation and the frequency simulation. Results. All the obtained results are validated by experimental measurements carried out at the Djillali Liabes University Sidi-Bel-Abbes in Laboratory of Applications of Plasma, Electrostatics and Electromagnetic Compatibility (APELEC). The experimental results obtained in common mode and in differential mode at low, medium and high frequencies are compared between the parallel boost test with and without electromagnetic compatibility filter.
Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects
(Національний технічний університет "Харківський політехнічний інститут", 2023) Kuchynskyi, Kostiantyn Arturovich; Kensytskyi, O. H.
An analysis of incidents linked to power units’ emergency disconnecting from network as a result of turbogenerators’ malfunction on the NPP of Ukraine is conducted. It is identified, that the reason of the majority of incidents is an insufficient reliability of the stator winding’s direct cooling system. Problem. The most problematic point in winding for today is the frontal parts, where, while cooling is reduced, there are not only thermal, but also thermomechanical loadings on an insulation appearing. The level of these loading depends on structural design of frontal parts and a character of violation of coolant agent circulation in a bar. In some cases they can exceed limit values. The spread and the quality of research on this issue for today are insufficient. Goal. The aim of the completed research is to determine the thermomechanical loading of insulation of stator winding bar in a powerful turbogenerator with a direct liquid cooling under condition when coolant circulation is malfunctioned. Methodology. A complex mathematical model of thermomechanical processes in an insulation of stator winding bar of a powerful turbogenerator is developed. It takes into account the real geometry of the winding bar, variable thermal loading of core elements in radial and axial directions, as well as ways of fixation of slot and frontal winding parts. Studies of thermomechanical processes in an insulation of stator winding bar of turbogenerator are conducted. Results. Values of mechanical displacement and stress for the different modes of malfunction are obtained. Areas of bar, where mechanical loading may exceed the boundaries of mechanical durability of material of insulation of stator winding are identified. With decline of coolant liquid consumption the radial displacement and stress in the winding insulation bar in the area, where the bar exits from the slot are increasing along with that the values of radial stress of insulation of the winding bar in places of frontal parts’ fixation exceed limit values. Practical significance. The offered mathematical models allow to realize calculation experiments and can be used in practice for development and validation of diagnostic systems, analysis, design and investigation of emergency situations during exploitation of turbogenerators on power stations of Ukraine.
Photovoltaic fault diagnosis algorithm using fuzzy logic controller based on calculating distortion ratio of values
(Національний технічний університет "Харківський політехнічний інститут", 2023) Lahiouel, Younes; Latreche, Samia; Khemliche, Mabrouk; Boulemzaoud, Lokmane
The efficiency of solar energy systems in producing electricity in a clean way. Reliance on it in industrial and domestic systems has led to the emergence of malfunctions in its facilities. During the operating period, these systems deteriorate, and this requires the development of a diagnostic system aimed at maintaining energy production at a maximum rate by detecting faults as soon as possible and addressing them. Goal. This work proposes the development of an algorithm to detect faults in the photovoltaic system, which based on fuzzy logic. Novelty. Calculate the distortion ratio of the voltage and current values resulting from each element in the photovoltaic system and processing it by the fuzzy logic controller, which leads to determining the nature of the fault. Results. As show in results using fuzzy logic control by calculating the distortion ratio of the voltage and current detect 12 faults in photovoltaic array, converter DC-DC and battery.