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Search results for: HIGH VOLTAGE POWER CONVERTERS
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Marek Olesz dr hab. inż.
PeopleWydział Elektrotechniki i Automatyki, Prodziekan ds. rozwoju dr hab. inż. Marek Olesz, prof. PG data urodzenia 1966 wykształcenie Politechnika Gdańska, Wydział Elektryczny (1990) stopień / tytuł naukowy doktor habilitowany – Politechnika Gdańska, Wydział Elektrotechniki i Automatyki (2017), doktor – Politechnika Gdańska, Wydział Elektrotechniki i Automatyki (1998) zatrudnienie Politechnika Gdańska: asystent stażysta (1989 –...
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Distribution Transformer with Multi-Zone Voltage Regulation for Smart Grid System Application
PublicationThe article presents four concepts of the multi-zone voltage regulation (MZVR) system. It is a combination of a distribution transformer with an on-load tap-changer, for step voltage regulation, and a power electronic converter, dimensioned for a fraction of MZVR power, realizing continuous voltage regulation, supplemented by a special switch, the so-called bypass. This allows voltage regulation at high resolution, wide range and...
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TRANSFER OF ELECTRIC ENERGY [2023/24]
e-Learning CoursesCourse content: Basic information on the structure of the power system, the major devices (components) for generation, transmission and distribution of electricity. Active and reactive power generation and their sources. Power supply networks. Tasks, structure, parameters. AC and DC transmission of electricity. Equivalent diagrams of the components of the power system. Steady state load flow calculation: currents, voltage,...
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TRANSFER OF ELECTRIC ENERGY [2022/23]
e-Learning CoursesCourse content: Basic information on the structure of the power system, the major devices (components) for generation, transmission and distribution of electricity. Active and reactive power generation and their sources. Power supply networks. Tasks, structure, parameters. AC and DC transmission of electricity. Equivalent diagrams of the components of the power system. Steady state load flow calculation: currents, voltage,...
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TRANSFER OF ELECTRIC ENERGY [2024/25]
e-Learning CoursesCourse content: Basic information on the structure of the power system, the major devices (components) for generation, transmission and distribution of electricity. Active and reactive power generation and their sources. Power supply networks. Tasks, structure, parameters. AC and DC transmission of electricity. Equivalent diagrams of the components of the power system. Steady state load flow calculation: currents, voltage, power,...
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TRANSFER OF ELECTRIC ENERGY [2024/25]
e-Learning CoursesCourse content: Basic information on the structure of the power system, the major devices (components) for generation, transmission and distribution of electricity. Active and reactive power generation and their sources. Power supply networks. Tasks, structure, parameters. AC and DC transmission of electricity. Equivalent diagrams of the components of the power system. Steady state load flow calculation: currents, voltage,...
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Cavitation resistance of OH18N9 steel alloyed with vaidus amount of TiC or Mn by means of laser beam. XIV International Symposium on Gas Flow, Chemical Lasers and High Power Lasers.
PublicationPrzedstawiono badania odporności kawitacyjnej stali OH18N9T po laserowym stopowaniu jej powierzchni węglikiem TiC oraz manganem. Wykazano, że wzbogacenie obrabianej stali manganem powoduje przemiany fazowe pod wpływem działania obciążeń kawitacyjnych, co przyczynia się do wzrostu odporności kawitacyjnej. Wzmacnianie stali węglikiem TiC powoduje natomiast zanik zdolności stali do wzmacniania odkształceniowego.
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Multilevel Converters
PublicationThe newest Special Section is intended to focus on recent research and trends in application of multilevel converters. Multilevel converters have been extensively developed over the last two decades and show several important advantages of power electronic circuits, such as: operation at high voltages, harmonics reduction, higher efficiency, modularity, smaller size and lower cost. Also, thanks to increasing interest in renewable...
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Impact of configuration of earth continuity conductor on induced sheath voltages in power cables
PublicationIn high voltage power cable systems a problem of induced sheath voltages exist. Due to these voltages electric shock and damage of non-metallic outer sheath of the cables may occur. Exposure to voltage of the outer sheath may be very high in case of earth fault with high value of earth current. In order to reduce induced sheath voltages an earth continuity conductor (conductors) along power cables is applied. Configuration of this...
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Impact of R/X ratio of distribution network on selection and control of energy storage units
PublicationThe interest in energy storage is still increasing. Energy storage units are installed in high voltage networks, medium voltage networks and low voltage distribution networks as well. These units are often used to improve power quality. One of the criteria for improving power quality is reducing voltage deviations. Depending on the type of network and specifying its R/X ratio, this criterion can be fulfilled by control of active...
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Problems of Connecting Wind Farms to the Power System with HV Cables
PublicationThis paper presents problems caused by connecting wind farms to a power system with high voltage cables. The author highlights possible problems with reactive power compensation, depending on the arrangement of the shunt reactor connection and settings of control systems for reactive power and voltage of the wind farm. The paper also discusses issues of increasing active power losses caused by a shunt reactor installation.
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Balancing energy consumption in limited power grid with active front-end and three phase dual active bridge system
PublicationPaper deals with simulation analysis of bidirectional power converters system for charging station of electric vehicle in condition of limited power source in city infrastructure. In case of incapability to provide additional power supply through the grid by virtue of historical, architectural and economic reasons it is possible to solve this issue by implementation of mobile battery-powered supply source. The proposed bidirectional...
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Janusz Nieznański prof. dr hab. inż.
PeopleJanusz Nieznański born in 1957 in Gdańsk. He received the M.Sc. degree in 1981, the Ph.D. degree in 1990, and the D.Sc. (‘habilitation’) degree in 1999, all from the Gdańsk University of Technology. Since 1981 he has been with the above university, where he is currently Professor of Electrical Engineering. His research and teaching interests include control, diagnostics, modeling and simulation of power electronic converters and...
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Estimation of the Maximum Permissible PV Power to be Connected to the MV Grid
PublicationIn recent decades, a significant increase in the share of renewable energy sources in power grids at various voltage levels has been observed. A number of articles have been published highlighting emerging problems in low-voltage grids with a large share of prosumers and in medium- and high-voltage grids to which photovoltaic (PV) plants are connected. The article analyzes the medium-voltage grid in terms of the possibility of...
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Nonlinear impedance as a function of A.C. voltage for fully crystallized 35Bi2VO5.5-65SrB4O7 glass measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrcial properties as a function of A.C. voltage for fully crystallized 35Bi2VO5.5-65SrB4O7 glass was measured by impedance spectroscopy method.
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Nonlinear impedance as a function of A.C. voltage of Bi2VO5.5 ceramic of thickness 1.63 mm was measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrical properties of Bi2VO5.5 ceramic of thickness 1.63 mm was measured by impedance spectroscopy method.
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Nonlinear impedance as a function of A.C. voltage of Bi2VO5.5 ceramic of thickness 4.03 mm was measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrical properties of Bi2VO5.5 ceramic of thickness 4.03 mm was measured by impedance spectroscopy method.
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Nonlinear impedance as a function of A.C. voltage of Bi2VO5.5 ceramic of thickness 2.91 mm was measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrical properties of Bi2VO5.5 ceramic of thickness 2.91 mm was measured by impedance spectroscopy method.
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Nonlinear impedance as a function of A.C. voltage for fully crystallized 45Bi2VO5.5-55SrB4O7 glass measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrcial properties as a function of A.C. voltage for fully crystallized 45Bi2VO5.5-55SrB4O7 glass was measured by impedance spectroscopy method.
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Research of Emergency Modes of Wind Power Plants Using Computer Simulation
PublicationThe aim of this study is to investigate changes in the wind power plant energy production parameters under the conditions of sudden wind changes and voltage drop. To achieve these goals, a simulation of operation of wind power plants was performed. Twelve wind turbines with variable rotational speed equipped with a Fuhrländer FL 2500/104 asynchronous double-fed induction generator (DFIG) were used, each with an installed capacity...
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High frequency test measurements on physical model of power transformer with use of FRAX analyzer Streszczenie. W niniejszym artykule przedstawiono pomiary testowe SFRA wykonane na modelu fizycznym transformatora elektroenergetycznego
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Voltage Transients Transfer over Medium Voltage Instrument Transformers
PublicationThis paper presents voltage harmonic transfer accuracy problems through voltage transformers which are used in power quality monitoring systems in medium and high voltage grids. A simplified lumped parameters circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number voltage transformers typically used in medium voltage grid has been tested in the conducted disturbances...
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Voltage Harmonics Transfer through Medium Voltage Instrument Transformers
PublicationVoltage transformers are widely used in power quality monitoring systems in medium and high voltage grids. This paper presents accuracy problems related to voltage harmonics transfer through instrument transformers. A simplified lumped-parameters wideband circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number of voltage transformers have been tested in the frequency...
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Four level inverter's DC bus voltage balancing with 3-terminal DAB converter
Publication—Multilevel inverters become more and more popular, especially in the medium or high voltage and high power applications. Unfortunately, some of inverter topologies require additional DC bus voltage balancing systems. This paper presents a novel approach to such systems, which is based on a multiple terminal DAB converter. Along with the voltage balancing function the proposed solution enables the connection of energy storage devices...
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Measurements of no-load and short-circuit parameters of power transformers with taps
Open Research Data1) The Laboratory LINTE^2 is a large research infrastructure operated by the Faculty of Electrical and Control Engineering at Gdańsk University of Technology, to be found in Gdańsk, Poland (54.3690 N, 18.6130 E).
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On the use of a charge balancing method for low energy measurements
PublicationThe paper presents the method for the estimation of the energy consumption of the low-power microcontroller-based devices. Due to high dynamics of the changes of the supply current of the tested devices during the operational cycle, the consumed energy estimation is not easy. In order to avoid disadvantages of known methods, the charge balancing method was employed similarly like in some types of A/D converters.
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Muhammad Jamshed Abbass Phd in Electrical Engineering
PeopleMuhammad Jamshed Abbass received the M.S. degree in electrical engineering from Riphah International University, Islamabad. He is currently pursuing the Ph.D. degree with the Wrocław University of Science and Technology, Wroclaw, Poland. His research interests include machine learning, voltage stability within power systems, control design, analysis, the modeling of electrical power systems, the integration of numerous decentralized...
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Nonlinear impedance as a function of A.C. voltage for annealed and next fully crystallized 50Bi2VO5.5-50SrB4O7 glass measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrcial properties as a function of A.C. voltage for annealed and next fully crystallized 50Bi2VO5.5-50SrB4O7 glass was measured by impedance spectroscopy method.
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Risk of power cables insulation failure due to the thermal effect of solar radiation
PublicationLow-voltage, as well as high-voltage power cable lines, are usually buried in the ground. The ampacity of the power cables in the ground mainly depends on the thermal resistivity of the soil, which may vary in a wide range. A common practice in power cable systems performance is to supply them from a pole of an overhead line. If so, a section of the line is located in free air and can be directly exposed to solar radiation. In...
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Metrological analysis of an computerized system of protection against electric shock in circuits with variable speed drives
PublicationDrive systems, that can be operated at variable speed, are equipped with power electronics converters. This causes distortion of the earth current, and consequently the need to take into account the use of proper protective devices in relation to earth current harmonics. This paper presents a system for protection against electric shock in circuits with power electronics converters and metrological analysis indicating the requirements...
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Voltage Harmonic Distortion Measurement Issue in Smart-Grid Distribution System
PublicationThis paper presents the investigation results ofvoltage harmonic transfer accuracy problems through voltagetransformers which are widely used in power quality monitoringsystems in medium and high voltage grids. A simplified lumpedparameters circuit model of the voltage transformer is presentedand verified by simulation and experimental investigations. Anumber voltage transformers typically used in medium voltagegrid has been tested...
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Starter for Voltage Boost Converter to Harvest Thermoelectric Energy for Body-Worn Sensors
PublicationThis paper examines the suitability of selected configurations of ultra-low voltage (ULV) oscilla-tors as starters for a voltage boost converter to harvest energy from a thermoelectric generator (TEG). Important properties of particularly promising configurations, suitable for on-chip imple-mentation are compared. On this basis, an improved oscillator with a low startup voltage and a high output voltage swing is proposed. The applicability...
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VSC converters control for offshore wind farms HVDC grid connection
PublicationThe paper proposes a voltage sourced converter (VSC) new control method. A well-known in the electric power systems correlation between voltage angle and active power and correlation between voltage and reactive power is used instead of feedforward control. This allows for a fast and almost independent control of active and reactive power flow.
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Nonlinear impedance as a function of A.C. voltage for glass 40Bi2VO5.5-60SrB4O7 annealed at 593 K and next fully crystallized measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrcial properties as a function of A.C. voltage for annealed at 593 K and next fully crystallized 40Bi2VO5.5-60SrB4O7 glass was measured by impedance spectroscopy method.
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Frequency Diagnostics of Transformer Insulating Parameters
PublicationIn the article is presented experimental analysis and diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. In the 1-st part of the article is described base theory about measurement and diagnostics insulating part (oil and paper) of power transformers. In the 2-nd part of article is described measuring method of insulating frequency diagnostics - frequency...
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Selection of energy storage units by genetic algorithm for mitigating voltage deviations
PublicationIn recent years, energy storage units have become very popular. They are applied both for economic and technical purposes. Unfortunately, the cost of such devices is still high and selecting their proper location and rated power have to be performed precisely. In this paper, a Genetic-Algorithm-based optimization method for selecting the best configuration of energy storage units in the power network is proposed. The presented...
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Failure analysis of a high-speed induction machine driven by a SiC-inverter and operating on a common shaft with a high-speed generator
PublicationDue to ongoing research work, a prototype test rig for testing high-speed motors/generators has been developed. Its design is quite unique as the two high- speed machines share a single shaft with no support bearings between them. A very high maximum operating speed, up to 80,000 rpm, was required. Because of the need to minimise vibration during operation at very high rotational speeds, rolling bearings were used. To eliminate...
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A Single-Carrier-Based Pulse-Width Modulation Template for Cascaded H-Bridge Multilevel Inverters
PublicationMultiplicity of the triangular carrier signals is a criterion for the extension of sinusoidal pulsewidth modulation, SPWM, to a number of output voltage levels per phase-leg in cascaded H-bridge (CHB) multilevel inverter (MLI). Considering medium and high voltage applications where appreciable number of output voltage levels from CHB MLI is needed, commensurate high number of carrier signals in either classical level- or phase-shifted...
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High Efficiency Dual-Active-Bridge Converter with Triple-Phase-Shift Control for Battery Charger of Electric Vehicles
PublicationAn optimal modulation scheme with triple-phase-shift (TPS) control could increase the efficiency in the entire load range for a dual-active-bridge (DAB) converter under wide output voltage range conditions. Therefore, this study proposes a convergent approach to TPS mode selection, coupled with an optimal modulation scheme, ensuring the circuit’s efficiency over the entire range in the realm of a high-power and high-efficiency...
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The effect of current delay angle on tripping of residual current devices
PublicationPower electronics converters applied in domestic or similar installations may utilize current delay (phase) angle control to change the level of transferred power. Due to application of such types of converters, earth fault current in the installation may be strongly distorted. The current distortion level depends on a value of current delay angle. This delay angle also influences the tripping threshold of residual current devices....
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Selected results of signal measurements in a ship power station with two generators working in parallel with the use of the Estimator/Analyzer instrument
Open Research DataThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/ Analyser (A/E v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering, of Gdynia Maritime University. The instrument performs a set of measurement functions that...
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Voltage variations and their reduction in a rural low-voltage network with PV sources of energy
PublicationRenewable sources of energy (RES), especially photovoltaic (PV) micro-sources, are very popular in many countries. This way of clean power production is applied on a wide scale in Poland as well. The Polish legal regulations and tariffs specify that every prosumer in a low-voltage network may feed this network with a power not higher than the maximum declared consumed power. In power networks with RES, the voltage level changes...
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Nonlinear impedance as a function of A.C. voltage for glass 40Bi2VO5.5-60SrB4O7 annealed at 473 K for 3h and next fully crystallized measured with impedance spectroscopy method at high temperature region
Open Research DataThe nonlinear electrcial properties as a function of A.C. voltage for annealed at 473 K for 3h and next fully crystallized 40Bi2VO5.5-60SrB4O7 glass was measured by impedance spectroscopy method.
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Multi-pulse VSC arrangements with coupled reactors
PublicationThis paper presents a novel approach to the multipulse VSC (Voltage Source Converter) arrangements based on several conventional inverter modules connected in parallel by using coupled reactors. This solution reduces the THD of the output voltage, despite the low switching frequency of transistors. The advantage of the proposed solution is also a relatively small rated power of the reactors. Proposed new arrangements for different...
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Przekształtniki tranzystorowe działające w trybie prądu trójkątnego
PublicationPrzekształtniki oparte na węgliku krzemu mogą być analizowane jako źródła napięcia lub prądu niezależnie od topologii przy odpowiednich parametrach filtru wyjściowego. Szczególnie interesujące są falowniki napięcia działające w trybie prądu trójkątnego. W referacie przedstawiono sterowanie trójfazowym falownikiem napięcia posiadającym właściwości źródła prądu. Pokazano, jak dobrać parametry filtru wyjściowego falownika. Oceniono...
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Harmonics produced by traction substations – computer modelling and experimental verification
PublicationVoltage and current harmonics have a detrimental effect on the components of a power system. Current harmonics may result in the overload and damage to power transformers. Voltage harmonics may result in, for example, damage to capacitor banks used to compensate reactive power. Devices which contribute to both current and voltage distortion include traction rectifiers. This paper presents results of the computer investigation of...
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Sensorless predictive control of three-phase parallel active filter
PublicationThe paper presents the control system of parallel active power filter (APF) with predictive reference current calculation and model based predictive current control. The novel estimator and predictor of grid emf is proposed for AC voltage sensorless operation of APF, regardless of distortion of this voltage. Proposed control system provides control of APF current with high precision and dynamics limited only by filter circuit parameters....
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Design of Intelligent Low-Voltage Load Switch for Remote Control System in Smart Grid
PublicationCurrent low-voltage load switches do not support remote disconnect/connect and real-time monitoring of a disconnect/connect state. Addressing to these issues, this paper presents a low-voltage load switch for a smart remote control system, which uses a one-chip microcontroller board and a DC step motor drive mechanism and provides the feedback on the switch status also. Arrears disconnect and full-pay connect control is implemented...
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An Ultra-Low-Energy Analog Comparator for A/D Converters in CMOS Image Sensors
PublicationThis paper proposes a new solution of an ultra-low-energy analog comparator, dedicated to slope analog-to-digital converters (ADC), particularly suited for CMOS image sensors (CISs) featuring a large number of ADCs. For massively parallel imaging arrays, this number may be as high as tens-hundreds of thousands ADCs. As each ADC includes an analog comparator, the number of these comparators in CIS is always high. Detailed analysis...
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Induced sheath voltages in 110 kV power cables – case study
PublicationThis paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse...