2023 № 2 Електротехніка і Електромеханіка

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Extended mixed integer quadratic programming for simultaneous distributed generation location and network reconfiguration
(Національний технічний університет "Харківський політехнічний інститут", 2023) Tami, Youcef; Sebaa, Karim; Lahdeb, Mohamed; Usta, Omer; Nouri, Hassan
Introduction. To minimise power loss, maintain the voltage within the acceptable range, and improve power quality in power distribution networks, reconfiguration and optimal distributed generation placement are presented. Power flow analysis and advanced optimization techniques that can handle significant combinatorial problems must be used in distribution network reconfiguration investigations. The optimization approach to be used depends on the size of the distribution network. Our methodology simultaneously addresses two nonlinear discrete optimization problems to construct an intelligent algorithm to identify the best solution. The proposed work is novel in that it the Extended Mixed-Integer Quadratic Programming (EMIQP) technique, a deterministic approach for determining the topology that will effectively minimize power losses in the distribution system by strategically sizing and positioning Distributed Generation (DG) while taking network reconfiguration into account. Using an efficient Quadratic Mixed Integer Programming (QMIP) solver (IBM ®), the resulting optimization problem has a quadratic form. To ascertain the range and impact of various variables, our methodology outperforms cuttingedge algorithms described in the literature in terms of the obtained power loss reduction, according to extensive numerical validation carried out on typical IEEE 33- and 69-bus systems at three different load factors. Practical value. Examining the effectiveness of concurrent reconfiguration and DG allocation versus sole reconfiguration is done using test cases. According to the findings, network reconfiguration along with the installation of a distributed generator in the proper location, at the proper size, with the proper loss level, and with a higher profile, is effective.
Super-twisting sliding mode control for brushless doubly-fed reluctance generator based on wind energy conversion system
(Національний технічний університет "Харківський політехнічний інститут", 2023) Oualah, O.; Kerdoun, D.; Boumassata, A.
Introduction. Recently, wind power generation has grown at an alarming rate in the past decade and will continue to do so as power electronic technology continues to advance. Purpose. Super-twisting sliding mode control for brushless doubly-fed reluctance generator based on wind energy conversion system. Methods. This paper deals with the robust power control of a grid-connected brushless doubly-fed reluctance generator driven by the variable speed wind turbine using a variable structure control theory called sliding mode control. The traditional sliding mode approach produces an unpleasant chattering phenomenon that could harm the system. To eliminate chattering, it is necessary to employ a high-order sliding mode controller. The super-twisting algorithm is one type of nonlinear control presented in order to ensure the effectiveness of the control structure we tested these controllers in two different ways reference tracking, and robustness. Results. Simulation results using MATLAB/Simulink have demonstrated the effectiveness and robustness of the super-twisting sliding mode controller.
Exploration and mitigation of power quality problems in radial distribution system by placing distributed generation through voltage stability index
(Національний технічний університет "Харківський політехнічний інститут", 2023) Manohara, M.; Veera Reddy, V. C.; Vijaya Kumar, M.
Introduction. Distributed generation has played an important role in many aspects of sustainability, such as improving voltage profiles and reducing power losses, in the distribution network. Problem. Frequent variation of loads causes many complications while placing and sizing of distributed generation in the radial distribution network, via quality of supply, and stability of the system. Goal of the paper is to investigate and mitigate the power quality issues towards stabilizing the system during distributed generations placed in the system under various loading conditions. Methodology. The line voltage stability index analyses and enhances the performance of the radial distribution network by effective sizing and location of distributed generation towards the objective function. Practical value. A standard test system IEEE-69 bus radial distribution network is used to understand through MATLAB environment.
Application of whale algorithm optimizer for unified power flow controller optimization with consideration of renewable energy sources uncertainty
(Національний технічний університет "Харківський політехнічний інститут", 2023) Laifa, Abdelaziz; Ayachi, Bilel
Purpose. In this paper an allocation methodology of Flexible Alternating Current Transmission Systems (FACTS) controllers, more specifically, the Unified Power Flow Controller (UPFC) is proposed. As the penetration of Renewable Energy Sources (RESs) into the conventional electric grid increases, its effect on this location must be investigated. Research studies have shown that the uncertainty of RESs in power generation influences the reactive power of a power system network and consequently its overall transmission losses. The novelty of the proposed work consists in the improvement of voltage profile and the minimization of active power loss by considering renewable energy sources intermittency in the network via optimal location of UPFC device. The allocation strategy associates the steady-state analysis of the electrical network, with the location and adjustment of controller parameters using the Whale Optimization Algorithm (WOA) technique. Methodology. In order to determine the location of UPFC, approaches are proposed based on identification of a line which is the most sensitive and effective with respect to voltage security enhancement, congestion alleviation as well as direct optimization approach. The optimum location of UPFC in the power system is discussed in this paper using line loading index, line stability index and optimization method. The objective function is solved using the WOA algorithm and its performance is evaluated by comparison with Particle Swarm Optimization (PSO) algorithm. Results. The effectiveness of the proposed allocation methodology is verified through the analysis of simulations performed on standard IEEE 30 bus test system considering different load conditions. The obtained results demonstrate that feasible and effective solutions are obtained using the proposed approach and can be used to overcome the optimum location issue. Additionally, the results show that when UPFC device is strategically positioned in the electrical network and uncertainty of RES is considered, there is a significant influence on the overall transmission loss and voltage profile enhancements of the network.
Modified discrete Fourier transform algorithm for protection of shunt compensated distribution line
(Національний технічний університет "Харківський політехнічний інститут", 2023) Jani, A.; Makwana, V. H.
Introduction. The response time of the relay plays vital role when fault occurs on the line. Various algorithms are adopted to increase the sampling rate of the relay which, in turn, improves the response time. Methods. Discrete Fourier transform and modified discrete Fourier transform are the two algorithms used to calculate the fundamental frequency phasor of the signal required by the relay to initiate trip command. It is known that discrete Fourier transform takes four to five cycles to produce the fundamental frequency phasor but it fails to deal with the decaying DC component. On the other hand, modified discrete Fourier transform improves the response time by removing the decaying DC component along with the other harmonics in just one cycle and a few samples. The aim of this paper is to cover discrete Fourier transform and modified discrete Fourier transform algorithms to analyze the performance of the three overcurrent and one earth fault relaying scheme for different types of faults occurring in the distribution system. Methodology. The concept of three overcurrent and one earth fault scheme is also explained in this paper for protection of shunt-compensated distribution system. The scheme is designed for variable power factor. MATLAB/Simulink is used as the software tool to validate the results obtained for various types of faults occurring in the system. The results are represented graphically to illustrate the time of response of the protection scheme when shunt compensators are connected at the receiving end of distribution network.
Bipolar DC output fed grounded DC-AC converter for photovoltaic application
(Національний технічний університет "Харківський політехнічний інститут", 2023) Sindhuja, R.; Padma, S.
Introduction. In recent years the usage of electricity has increased tremendously as the electrical needs and loads got increased. Hence the researchers focused on the electricity generation from renewable sources in order to promote sustainable green environment. Owing to the lesser cost and more reliable high efficiency system with reduced use of equipments became prominent for the grid connected photovoltaic single phase systems. The novelty of this proposed converters are to reduce total power loss and to analyze the performance of the converter under various modulation index and to have lesser harmonics using sinusoidal pulse width modulation technique for both T-type and F-type inverter. Interest of the work is to merge two DC-DC converters which have same output voltage in order to have transformer less utilization of power. This has given pathway to develop a new DC-DC converter network by merging the common input nodes of CUK and SEPIC converter. Purpose. This similar structure of both converters made it easy to combine the input stages of and to get bipolar output. Methods. Here we can get bipolar output without the utilization of transformer which minimizes the overall size of the proposed system. In this paper, a combined CUK-SEPIC based grid connected transformerless inverter for photovoltaic application is suggested. Results. The suggested converter is simulated using MATLAB and the results were discussed. Further the circuit is extended with a 1 kW F-type inverter to demonstrate grid connection of the converter. Practical value. This converter can be implemented for photovoltaic applications for obtaining the bipolar DC output from the DC source.
Sliding mode approach for control and observation of a three phase AC-DC pulse-width modulation rectifier
(Національний технічний університет "Харківський політехнічний інститут", 2023) Sakri, Djamel; Laib, Hichem; Farhi, Salah Eddine; Golea, Noureddine
Introduction. For AC-DC conversion systems, the electrical systems typically use thyristor or diode bridge rectifiers, which have relatively poor performance. Nowadays, three-phase pulse-width modulation rectifiers are widely applied in various applications for their well-known intrinsic benefits, such as adjustable DC link voltage, unity power factor, bidirectional power flow and very low total harmonic distortion. Purpose. The objective of this work is to achieve better stability and dynamic performance using sliding mode strategy for control and observation. Methods. For that purpose, first a sliding mode controller is introduced on the DC-link side to ensure a fast and accurate response of the output load voltage. Then, the sliding mode approach is employed to control the quadrature and direct components of power to maintain the input power factor at unity. Finally, this approach is used to design two observers for grid voltage estimation and online variation of load resistance. To overcome the problem associated with the use of the classical low-pass filter, an adaptive compensation algorithm is used to compensate the attenuation of the amplitude and phase delay of the observed grid voltages. This algorithm is based on the use of the two low-pass filters in cascade and ensures the minimization of chattering. Results. Comparative studies have been carried out between sliding mode control method for controlling the three-phase AC-DC pulse-width modulation rectifier and other conventional techniques. The validation by simulation and the tests carried out gave very satisfactory results and proved the effectiveness and feasibility of the sliding mode for both control and observation of three phase pulse-width modulation rectifier.
MATLAB-Simulink environment based power quality improvement in photovoltaic system using multilevel inverter
(Національний технічний університет "Харківський політехнічний інститут", 2023) Priyanka, G.; Surya Kumari, J.; Lenine, D.; Srinivasa Varma, P.; Sneha Madhuri, S.; Chandu, V.
Introduction. In this world of technical advancement, conventional resources are at the stage of destruction. To avoid such problems, we are going to use an alternative energy source namely solar by photovoltaic effect. The demand for multilevel inverters increased as they are used for different dynamic (high) voltage and dynamic (high) power appliances as they are capable of producing the output wave shape with low total harmonic distortion. Novelty. A new multilevel inverter is used in adding a (bidirectional) two way switch in between the capacitor and a traditional H-bridge module. This produces a better sine wave. By series connection of these two H-bridge modules, nine levels output voltage including zero is possible. The purpose of the proposed topology is reduction in the number of switches and it gives the good result with comparatively less power loss when it is compared with the other normal basic traditional inverters of the same output quality. Methods. In this paper, sinusoidal pulse width modulation technique is used for the working of the switches in the multilevel inverter. The results are verified by using simulation and also experimental setup is done. From the results it is observed that the proposed topology with reduced number of switches gives lower electromagnetic interference, lower harmonic distortion. Practical value. The total harmonic distortion value in the simulation is 14.4 % and practically it is 13.8 %.
Implementation of a new flux rotor based on model reference adaptive system for sensorless direct torque control modified for induction motor
(Національний технічний університет "Харківський політехнічний інститут", 2023) Saifi, R.
Introduction. In order to realize an efficient speed control of induction motor, speed sensors, such as encoder, resolver or tachometer may be utilized. However, some problems appear such as, need of shaft extension, which decreases the mechanical robustness of the drive, reduce the reliability, and increase in cost. Purpose. In order to eliminate of speed sensors without losing. Several solutions to solve this problem have been suggested. Based on the motor fundamental excitation model, high frequency signal injection methods. The necessity of external hardware for signal injection and the adverse influence of injecting signal on the motor performance do not constitute an advantage for this technique. Fundamental model-based strategies method using instantaneous values of stator voltages and currents to estimate the rotor speed has been investigate. Several other methods have been proposed, such as model reference adaptive system, sliding mode observers, Luenberger observer and Kalman filter. The novelty of the proposed work consists in presenting a model reference adaptive system based speed estimator for sensorless direct torque control modified for induction motor drive. The model reference adaptive system is formed with flux rotor and the estimated stator current vector. Methods. The reference model utilizes measured current vector. On the other hand, the adjustable model uses the estimated stator current vector. The current is estimated through the solution of machine state equations. Practical value. The merits of the proposed estimator are demonstrated experimentally through a test-rig realized via the dSPACE DS1104 card in various operating conditions. The experimental results show the efficiency of the proposed speed estimation technique. Experimental results show the effectiveness of the proposed speed estimation method at nominal speed regions and speed reversal, and good results with respect to measurement speed estimation errors obtained.
The method of multi-objective parametric design of magnetic field active canceling robust system for residential multy-story buildings closed to double-circuit overhead power lines
(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.
Aim. Development the method of multi-objective parametric design for robust system of active canceling of magnetic field based on binary preference relations of local objective for multi-objective minimax optimization problem. Methodology. Spatial location coordinates of the compensating winding and the current in the shielding winding were determined during the preference-based multi-objective parametric design of systems of active canceling based on solution of the vector minimax optimization, in whith the vector objective function calculated based on Biot-Savart's law. The solution of this vector minimax optimization problem calculated based on nonlinear Archimedes algorithm. Components of Jacobi matrix and Hesse matrix calculated based on multi-swarm multi-agent optimization. Results. Theoretically and experimentally confirmed the effectiveness of reducing the level of the magnetic field in residential multy-storey old building of a doublecircuit overhead power transmission lines with a barrel-type arrangement of wires by means of active shielding with two compensation winding. Originality. The method of multi-objective parametric design for robust system of active canceling of magnetic field based on binary preference relations of local objective for multi-objective minimax optimization problem is developed. Practical value. It is shown the possibility to reduce the level of magnetic field in residential multy-storey old building closed to double-circuit overhead power transmission lines with a barrel-type arrangement of wires by means of system of active canceling with two canceling winding to a level safe for the population with an induction of 0.5 μT.