Grzegorz Komarzyniec

Inrush Current of Superconducting Transformer

Inrush current in superconducting transformers is a little-known phenomenon. Because of its high values and long time, it may lead to loss of superconductivity in transformers windings. In the article, we present results of inrush current measurements in two superconducting transformers of the same power but different winding geometries. The results were confronted with inrush current registered for a transformer with copper windings. The results suggest different parameters of inrush current for superconducting transformers as compared to transformers with copper windings. This article is an introduction to a series of studies on the phenomenon of superconducting transformer inrush current.

Modeling of the Temperature Distribution in Arc Discharge Plasma Reactor

Abstract For pollution control the non-thermal plasma seems to be the most convenient source of energetic electrons and chemically active species. In the electrical discharges the non-thermal plasma condition at atmospheric pressure can be obtained with fast gas flow through the discharge chamber volume, like in DC glow discharge or AC gliding arc discharge. The electrons temperature and its volumetric distribution is one of the fundamental parameters that should be study if we want to obtain the non-equilibrium low temperature plasma conditions in given geometry of the plasma reactor. These conditions depend on the kind of plasma gas and its velocity, geometry of the gliding arc reactor and on parameters of the power supply system. Paper presents a simplified mathematical model of the two -electrode gliding arc reactor to determine electron temperature and its distribution. Results of calculations are useful for selection of the power supply systems parameters and their design as to ensure the non-equilibrium state of gliding arc discharge plasma. Further calculations aim at three-and multielectrode reactors and three-dimension temperature distribution.

Arc Plasma Reactor Power System with 5-Limb Transformer

Abstract The arc plasma reactors are especially suitable for treatment of big volumes of exhaust gases emitted to the atmosphere during various technological processes. They can operate at three-phase power system and can be connected in series or in parallel to the gas flow. Their proper operation require power supply systems that should ionize the inter-electrode zone and maintain the cyclic and non-equilibrium operation of the arc discharge after ignition while presenting stable and reliable operation. Transformers of special construction are the basic elements of all of arc discharge plasma reactors power systems. Paper presents results of investigation of 5-limb transformer as a power supply for the arc plasma reactor. The possibility to take advantage of the voltage induced in the yokes of this kind of transformer for ignition of the discharge is also discussed.

Solar energy for soil conditioning

Constant increase of energy consumption by growing population and shortening of natural resources will impose greater limitations of electric energy consumption by various treatment technologies. Shifting from large-scale treatment facilities powered from conventional sources to autonomic, small, and medium size installations supplied from renewables is one of the possible solutions. Results of ozone soil treatment are presented. PV panels supplied, on-site installation for soil treatment is proposed.

Autonomous Water Treatment Installation Energized from PV Panels

Abstract Low temperature plasma generated by dielectric barrier discharge is well known source of active specious that can be applied in processes of water, air and soil treatment. Ozone generators can be energized from solar energy. The solution is specially advantageous in the regions with satisfactory solar radiation situated in remote terrains far from power network. Paper presents results of research carried out at the experimental stand as well as at the prototype of autonomous water treatment installation for domestic purposes, energized from photovoltaic panels.

Properties of gliding arc (GA) reactors energized from AC/DC/AC power converters

Industrial plasma reactors design requires knowledge of their characteristics at different conditions of power supply system. Gliding arc plasma (GAD) characteristics are very sensitive either on these parameters or the properties and dynamic of the plasma gas (velocity, kind of gas and its composition). Paper presents the results of investigations of the atmospheric pressure low temperature GAD plasma properties controlled by a power electronic inverter and by a transformer type power supply system. Measurements are performed for discharges in argon, nitrogen and their mixtures in three-electrode plasma reactor. AC/DC/AC inverter has operated as a current and voltage source.

Temperature increase of the primary winding of a 14 kVA HTS transformer during the flow of the switching current

When switching on the HTS transformer, through its windings flows an electric current exceeding the value of the critical current of the superconductor. This current deprives the primary winding of its superconducting property, which can result in the winding’s thermal damage. The temperature reached by the winding during the flow of the inrush current was calculated. For this purpose, measurements of a 13.8 kVA HTS transformer and derived formulae were used. Streszczenie. Przy włączaniu transformatora HTS przez jego uzwojenia przewodzony jest prąd elektryczny o wartości przekraczającej wartość prądu krytycznego nadprzewodnika. Prąd ten powoduje utratę stanu nadprzewodzenia uzwojenia pierwotnego, co może skutkować jego termicznym uszkodzeniem. Obliczono temperaturę jaką osiąga uzwojenie w trakcie przepływu prądu włączania. Posłużono się w tym celu pomiarami transformatora HTS o mocy 13,8 kVA i wyprowadzonymi wzorami. (Wzrost temperatury uzwojenia pierwotnego transformatora HTS o mocy 14 kVA w czasie przepływu prądu włączania)

The influence of the geometry and resistance of the high voltage winding of the HTS transformer on the inrush current parameters

In this work we have analysed the inrush current of superconducting transformers. The value and time of decay of the inrush current depend on the radial and axial dimensions of the high voltage winding. In the case of superconducting transformers, these parameters also depend on the state of the superconductor. Analysis was made on the basis of measurements of the superconducting transformer inrush current of 8 kVA and 13.8 kVA with different winding geometries. Słowa kluczowe: transformator, nadprzewodnictwo, transformator nadprzewodnikowy, prąd włączania

13,8 kVA transformer with windings made of YBCO HTS tapes

This paper presents the design of one-phase transformer with the windings made of second generation of HTS tapes. The no-load operation and transformer short-circuit measurement characteristics were deleted from the measurements. The values of short-circuit impedance, its components and power losses were specified. In closing remarks comments were made on the designing of superconductor transformers and operational conclusions. Słowa kluczowe: transformator, nadprzewodnictwo, taśma nadprzewodnikowa.

Impact of critical current values in HTS transformer winding on decay time of inrush current

This paper presents mathematical analysis of the first inrush current pulse for transformers with windings made of superconducting materials. Formulas are derived hereby, allowing for calculation of pulse duration. Moreover, dependences are shown which allow for specifying the time when transformers primary winding is in the resistive state. Streszczenie. W artykule przedstawiono analize matematyczną pierwszego impulsu prądu wlączania transformatora z uzwojeniami wykonanymi z materialu nadprzewodnikowego. Wyprowadzono wzory umozliwiające wyliczenie czasu trwania impulsu. Podano rowniez zalezności umozliwiające określenie czasu przez jaki uzwojenie pierwotne transformatora znajduje sie w stanie rezystywnym. (Wplyw wartości prądu krytycznego uzwojenia transformatora HTS na czas zaniku prądu wlączania)