Ruslan Vlasenko’s research while affiliated with Donetsk National University of Economics and Trade named after Mykhailo Tugan-Baranovsky and other places

Purpose. The purpose of the article is to investigate the modes of operation of a three-phase active power filter in the composition of an autonomous electrical network when connected to a network of three-phase nonlinear load of different spectral character. Methodology. For the purposes of the research, we used the provisions of pq-theory of power, theory of electric circuits, theory of automatic control, mathematical modeling in the Matlab package. Findings. The obtained graphs and spectral composition of the network voltage, load current, which allows to evaluate the efficiency of the use of a active power filter in the filtering mode in the autonomous electric network, which is a synchronous generator. Originality. Efficiaty parallel operation of a active power filter in the filtering mode with a synchronous genera-tor under sharply variable non-linear loading is proved. Practical value. Using the proposed method will allow to create a three-phase active power filter for its applica-tion in autonomous electrical networks, represented by a synchronous generator with automatic control of the excita-tion voltage.

Arc furnace is a common smelting furnace for metallurgical production. At the same time, there is a stochastic operating mode in the arc furnace, that widespread in the industry. The combustion arc in the arc furnace is accompanied by a generation to the power supply network of reactive power, higher harmonics and there is asymmetry of currents. This leads to fluctuations not only in reactive power, but also causes fluctuations in active power. Static compensating devices such as condenser batteries, power passive filters, synchronous compensators do not have time to react to the sharply variable operating mode of the arc furnace. The latest advances in the compensation of inactive components power are the use of three-phase active power filters, which do not have the phenomenon of resonance of voltages and currents, as well as they react to change the load during their work. In the work the model of the three-phase active power filter with an arc furnace to the visual modeling environment is synthesized. The parameters of the arc fur-nace substitution scheme are brought to the low side of the electric transformer the furnace. Parameters of three-phase active power filter are calculated for this type of arc furnace. In the course of the study, ob-tained the data of the consumption of active and reactive power of the load and the network, as well as the coefficient of distortion of the sinusoidality of the current load curve and the network. The received oscillo-gram of network voltage, load current, current active power filter, network current and spectral diagram of higher harmonics of load current and network. All the results obtained were analyzed and perform conclu-sions for them.

Purpose. Determination of the analytical interrelation of Clarke and Fortescue transformation for an asymmetric sinusoidal system of currents of a three-phase four-wire network. Methodology. To find the way for the use of the direct, reverse and zero sequences as components of the power circulating in the intersection of the four-wire current line, a problem is set to determine the interrelation of Clarke (α-β-0) and Fortescue (1-2-0) transformations. An analysis of the order of calculation of the direct, reverse and zero sequences components is carried out for the general case and for every separate phase. Comparison of Clarke transformation for separate sequences is performed using Euler formulae in an exponential form. Analytical relations determining the components of the current and voltage of direct and reverse sequences in domain α-β-0 are obtained. The said relations are used as the basis for instantaneous power decomposition in the use of p-q theory. The performed numerical calculation of current and voltage components, as well as power according to p-q theory, confirms the obtained analytical results. Findings. Interrelation of direct and reverse sequence conversion of voltages (currents) in domain 1-2-0 (Fortescue transformation) with voltages (currents) in domain α-β-0 (Clarke transformation) is analytically substantiated, which makes it possible to separate in the latter the components caused by the action of direct and reverse sequences. Originality. Analytical determination of direct, reverse sequence components in domain α-β is proposed to use these components during calculation of instantaneous power according to p-q theory for four-wire lines. Practical value. The obtained results present a part of the analysis of electric power components in electrical four-wire networks with asymmetric parameters of the mode and they can be developed for networks with nonsinusoidal voltages and currents.

ua Purpose. Development of a subsystem of the previous phase capacitor charging power of parallel active filter as part of the control system. Methodology. Based on the analysis set out in known publications implement subsystem previous charge the capacitor, which provides support and control DC voltage in a given range of compensation provided in the inactive components of power. On the basis of the order of formation current power active filter selected parameter is used to set the intensity of battery-power. The algorithm of compensation, further comprising adjusting the current power active filter equivalent to the value of charging power under conditions of capacitor voltage deviation limits specified range. Results. Based on an algorithm taking into account the known technical solutions developed active filter circuit of the power subsystem charge the capacitor. Through modeling experiments implemented in algorithm modes and the correct conclusions. It is noted that at the beginning of the scheme is unmanageable because of counter-diode circuit, causing the current cast, which limited inductance range of network power active filter. Originality. When using SAF quality testing given current vary depending on the power circuit and the voltage level of the ca-pacitor. The voltage capacitor for handling should be higher than the voltage, in some cases-much higher. In a famous study dedicated modes SAF authors examined the scheme processes and modes of position provide the necessary current levels SAF network, but the formation of the charge in the capacitor DC link remains unexplored. There are technical solutions that provide the capacitor charging process with certain conditions and requirements, but the use of additional circuitry to implement a charge capacitor when SAF leads to complications schematics and accordingly the use of appropriate controls. Practical value. In the course of an experiment for the following modes: charge the capacitor SAF mode of compensation for the load conditions, compensation for increased load conditions. References 13 Figure 3. Key words: active power filter, battery capacity, charge level of the capacitor, pq-power theory.

The paper deals with assessment of power components according to ІЕЕЕ 1459-2010 standard during operation of a three-phase active power filter in complex with a nonlinear unbalanced load under the conditions of balanced and unbalanced network voltage. Correction of the algorithm of Fryze theory taking into consideration the cases of load currents' and network voltage unbalance has been proposed. Fryze algorithm correction is performed with determination of power and currents values according to ІЕЕЕ 1459-2010 standard. A comparative assessment of the quality of operation of the active power filter has been carried out with the use of algorithms based on different power theories (pq-theory, Fryze theory). OCENA KOMPONENTÓW MOCY SIECI ELEKTRYCZNEJ PODCZAS PRACY AKTYWNEGO FILTRA WEDŁUG IEEE 1459-2010 STANDARD Streszczenie. Praca dotyczy oceny składników energetycznych, zgodnie z normą ІЕЕЕ 1459-2010 podczas działania trójfazowego filtru aktywnego w kompleksie z nieliniowym o obciążeniu niesymetrycznym w warunkach zrównoważonego i niezrównoważonego napięcia sieci. Autorzy zaproponowali algorytm korekcji oparty na teorii Fryzego. Algorytm ten został opracowany z określeniem wartości mocy i prądów ,zgodnie z normą ІЕЕЕ 1459-2010. Porównawcze oceny jakości działania filtru aktywnego zostały przeprowadzone z wykorzystaniem algorytmu na podstawie teorii mocy (pq-teorii, teoria Fryzego).

Power active filters are widespread devices and attract the attention of researchers due to their multifunctional properties, such as reactive power compensation, filtering of higher current harmonics and load balancing. The IGBT modules as a switches of converter are used to build the modern power filter. An important aspect in designing the device is the system for forming the control pulses for these switches. The paper deals with the most common systems for forming control pulses, which are based on the relay control methods and pulse-width modulation control methods. A comparative study of two control systems was carried out and the time diagrams of the filter currents and their spectrums were obtained. According to the performed research the conclusions with the recommendations are presented.