LUBLIN UNIVERSITY OF TECHNOLOGY
Faculty of Electrical Engineering and Computer Science
Institute of Fundamentals of Electrical Engineering and Electrotechnology
MSc. Grzegorz Komarzyniec
ANALYSIS OF THE OPERATION OF A FIVE-COLUMN TRANSFORMER
IN THE POWER SYSTEM OF THE ARC PLASMA REACTOR
dissertation
Promoter: prof. emergency PL, Ph.D. engineer Henryka Danuta Stryczewska
Lublin 2008
1. Introduction
The history of the use of plasma in technology begins around 1800, when Sir Humphry Bartholomew Davy began research on arc discharge in the air. Eight years later, Davy develops the arc lamp, and in 1878, Ernst Werner von Siemens invents and patents an arc furnace for melting steel. In 1901, Guglielmo Marconi used an electric arc to transmit radio across the Atlantic. At the same time, research work on discharges in gases is ongoing. The first ionized gas was examined and described in 1839 by Michael Faraday, and in 1879 Sir William Crookes pointed out that discharges in gases can be treated as the fourth state of matter. Many years later, in 1923, Irving Langmuir introduced the term plasma. Since Langmuir's time, the concept of plasma has changed and now plasma is understood as an ionized gas that is a quasi-neutral mixture of free ions, electrons and neutral particles. The energy of plasma particles can range in a very wide range from 0.2 eV to 2 MeV, which is why it can vary greatly in the degree of ionization and properties. Due to the fact that plasma can occur in a wide range of temperatures and pressures, it is divided into low-pressure and high-pressure plasma, as well as low-temperature (cold) and high-temperature (hot) plasma. Low-temperature plasma is usually considered to be a partially ionized gas located in the temperature range from 2,000 K to 30,000 K. High-temperature plasma is an almost completely ionized gas in which most of the ions are multiply ionized and some may be free nuclei stripped of all electrons. This plasma covers the temperature range from 10 million K to 1,000 million K. High-pressure plasma covering the pressure range above 100 kPa is similar to high-temperature plasma in terms of thermodynamic equilibrium. However, at pressures lower than 100 Pa, a low-pressure plasma occurs, characterized by thermodynamic imbalance.
There is no clear boundary between gas and plasma, hence the transition from gas to plasma is considered to be the moment when a small amount of charged particles of matter changes its properties and electrical conductivity appears. Plasma is the normal state of matter at temperatures of 10,000 K and higher. Stars and interstellar gas are made of plasma, which makes it the most common
the state of matter found in the Universe. In terrestrial conditions, it occurs in the aurora borealis and lightning. For technical and laboratory purposes, low-temperature plasma is produced, most often by electric discharges in the gas, in devices called plasma reactors. Plasma generated in this way is becoming more and more widely used in many fields of science and industry. New types of plasma reactors are being created, and existing ones are being improved and improved. Currently, plasma is used in metallurgy and foundry, machine construction, microelectronics industry, plasma chemistry, space research, medical laboratories and environmental protection. Protection of the natural environment is a priority area in the development of civilization. Modern technologies offer many solutions that can be or are used in environmental protection, but particular attention has been paid to plasma methods [1], [2], [3], [4]. One of the more promising technologies is the use of low-temperature plasma generated at atmospheric pressure in sliding arc discharge reactors [30], [31]. In these reactors, at the moment of ignition, the discharge takes the form of a short arc, which is in a state of thermodynamic equilibrium. Under the influence of electrodynamic and gas-dynamic forces acting on the arc column occurring in the discharge chamber, the discharge moves along the electrodes. As a result of a several-fold increase in length and volume, the discharge reaches the state of a long arc in a non-equilibrium state. The arc develops as long as the power supply system is able to cover the discharge energy losses to the environment. The duration of one reactor operation cycle is influenced by many factors, including: the dimensions and shape of the electrodes, the flow rate of the gaseous medium through the discharge chamber, the chemical compositionof the gas in which the discharge takes place, the voltage and current of the electrodes, and the frequency of the supply voltage.
The advantages of plasma and the wide range of applications of plasma reactors mean that interest in plasma is increasing, and currently this issue is being studied by research centers in Japan, the United States, France and Russia. In Poland, research in this field has been conducted for several years at the Institute of Fundamentals of Electrical Engineering and Electrotechnology of the Lublin University of Technology and many other research centers in Częstochowa, Gdańsk, Łódź, Poznań, Szczecin, Warsaw and Wrocław.
Conducting any process using plasma should be based on knowledge of its properties and mastering the methods of obtaining it, because plasma cannot be stored and transported. Therefore, plasma research around the world focuses on achieving controlled plasmachemical reactions. The repeatability of processes carried out with its participation largely depends on the stability of the parameters of the generated plasma. The plasma parameters necessary for the correct course of the reaction are obtained by controlling the conditions in which the discharge burns, i.e. the chemical composition of the plasma-forming gas, its pressure and humidity, and by controlling the parameters of the material subjected to plasma treatment. A properly selected power system is of great importance for generating plasma with appropriate parameters. Its solutions must meet the requirements of plasma reactors [65], [66], which are special electrical energy receivers with non-linear characteristics and rapid changes in the instantaneous values of currents, voltages and conductance of the discharge space.
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