Wyniki 1-4 spośród 4 dla zapytania: authorDesc:"Fyodor ROMANYUK"

Digital filters to separate the first and second harmonics of signals in microprocessor-bases protection of electrical installations equipped with transformers DOI:10.15199/48.2018.07.11

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In electrical installations equipped with power transformers when they are turned on with no load under voltage, an inrush of the magnetizing current (IMC) occurs in some cases of voltage recovery after disconnection of external short circuits (SC) and in some other cases. Under the influence of mentioned inrush overcurrent protection of electrical installations might falsely trigger. Prevention is possible either by means of an increase of the current of protection operation (that is not always acceptable), or by the implementation of the protection blocking at the IMC occurrence. The classic way of locking protection when IMC takes place is based on tuning-out by harmonics content. The content of low harmonics in the current can be the criterion for protection actuation, and the presence of the current harmonics of a higher order can indicate the appearance of the IMC and their use to block the action of protection. Various options of the lock, based on the above provision, are presented in [1]. Herewith, one of these implementations involves the use of the amplitude of the second harmonic current of negative sequence and of the amplitude of the current of the first harmonic of direct sequence, according to which a lock parameter is determined [2]. In order to obtain the necessary information, from the corresponding currents with the aid of frequency filters the harmonics with frequencies of 100 and 50 Hz are separated, according to which their sine and cosine orthogonal components (OC) are formed. In accordance with the specified OC or with the readouts of instantaneous values of one of them [3] amplitudes of currents of the first and second harmonics for the subsequent determining of the lock parameter are calculated. The article describes the principle of implementation of the respective filters that makes it possible to obtain eventually current amplitudes of the first and the second harmonics currents and examines [...]

Validation of mathematical model of differential protection DOI:10.12915/pe.2014.03.042

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Comparison of results of mathematical modeling and field tests of a transformer differential protection is presented in this paper. An inrush current mode, external two-phase and three-phase faults are considered. Proposed mathematical model can be used to test differential protection in different modes of transformer operation. Streszczenie. W artykule przedstawiono porównanie wyników badań i rezultatów modelowania matematycznego zabezpieczeń różnicowych transformatorów. Rozpatrzono przypadki prądów rozruchowych oraz zwarć dwufazowych i trójfazowych. Zaproponowany model matematyczny może być używany do testowania zabezpieczeń różnicowych w różnych trybach pracy transformatorów. (Walidacja modelu matematycznego zabezpieczenia różnicowego). Keywords: relay protection, transformer differential protection, mathematical model, field experiment. Słowa kluczowe: przekaźnik, zabezpieczenie różnicowe transformatora, model matematyczny, pole doświadczalne. doi:10.12915/pe.2014.03.42 Introduction Differential stage is one of the main protections of power transformers. Problems of a choice of analog and digital filters, a type of operating characteristic, offsetting algorithms from inrush current, from overexcitation of the transformer core, from external faults accompanied with current transformers (CT) saturation have to be solved during the development of a transformer differential protection [1]. An important step of differential protection device development is a complex testing of protection algorithms in a wide range of transformer operation conditions. Testing methods include:  laboratory tests with some special test equipment (for example, Omicron CMC 356 or RETOM-61), which generates currents corresponding to different operation modes of power transformer. It is possible to check operation characteristic and the second and fifth harmonics restrain in laboratory. Also using test equipment allows checking differential prot[...]

Wye-connected current transformers simplified model validation in MATLAB-Simulink DOI:10.15199/48.2015.11.67

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This paper presents the wye-connected current transformers (CTs) simplified mathematical model with the initial data based on nominal parameters (nameplate data) of the simulated CT. Designed user-friendly graphical interface allows to specify the CT data (nominal parameters, remanence and burdens) in convenient form. Results of the carried out experiments confirmed the CT model validity. Streszczenie. Niniejszy artykuł przedstawia uproszczony model matematyczny układu przekładników prądowych połączonych w gwiazdę, w którym dane źródłowe oparte zostały o parametry znamionowe (tabliczkę znamionową) symulowanych przekładników. Przyjazny dla użytkownika interfejs graficzny pozwala na określenie danych przekładników prądowych (parametry znamionowe, magnetyzm szczątkowy, obciążenia) w wygodny sposób. Wyniki przeprowadzonych eksperymentów potwierdziły poprawność modelu przekładnika prądowego (Weryfikacja eksperymentalna uproszczonego modelu połączenia gwiazdowego przekładników prądowych w programie MATLAB-Simulink). Keywords: current transformer model, relay protection, magnetization curve, saturation, Simulink, Matlab, SimPowerSystems. Słowa kluczowe: model przekładnika prądowego, przekaźniki zabezpieczeniowe, krzywa magnesowania, nasycenie, Simulink, Matlab, SimPowerSystems. Introduction Information sources about the currents of the protected object are current transformers (CTs), which secondary currents are transmitted to the digital relay protection analog inputs. Because of CT core saturation in emergency mode secondary current waveform may substantially differ from the primary current waveform. To evaluate the digital relay behavior nowadays are widely used test sets which allow to deliver current signals (that are equivalent in form and capacity of the CT secondary currents) to the digital relay analog inputs. One way to obtain such data signals is the mathematical modeling method. It allows with the help of computer simulation usi[...]

Application of a software package for transmission line digital overcurrent protection testing in the MATLAB-SIMULINK environment DOI:10.15199/48.2017.05.31

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The article proves the possibility of implementing a software package for digital overcurrent protection testing in the Matlab-Simulink environment. A comparison of simulation results obtained with the use of the proposed software package with the results obtained with the use of the other software, as well as with the calculations of transient processes has been performed. The parameters calculation methods of the proposed software package are presented. Streszczenie. Artkuł udowadnia możliwość implementacji pakietu oprogramowania przeznaczonego do badania cyfrowego zabezpieczenia nadprądowego w środowisku Matlab-Simulink. Przeprowadzono porównanie wyników uzyskanych za pomocą proponowanego pakietu oprogramowania i innego oprogramowania, jak również obliczeń stanów przejściowych. Zaprezentowano metody wyznaczania parametrów proponowanego pakietu oprogramowania. (Zastosowanie pakietu oprogramowania przeznaczonego do badania cyfrowego zabezpieczenia nadprądowego linii przesyłowej w środowisku MATLAB-SIMULINK). Keywords: software package, Simulink, Matlab, SimPowerSystems, digital overcurrent protection, model, current transformer Słowa kluczowe: pakiet oprogramowania, Simulink, Matlab, SimPowerSystems, cyfrowe zabezpieczenie nadprądowe, Introduction Digital protection testing at the stage of their development is being performed with the help of software packages (SP) that simulates the digital protection analogue inputs supplying with the currents and voltages that are similar in volume and waveform to the actual secondary signals of current and voltage under the conditions of real exploitation of the protected object. A comprehensive mathematical model, that calculates the input signals of relay protection, is being prepared for the generalized electric power object (GEO). Model of GEO can be realized either on the basis of mathematical descriptions of electric and magnetic circuits of the modeled elements, or in systems of dynamic [...]

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