Temat: system impedance - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Assessing system impedance based on data regrouping
Autorzy:: Xu, Shuangting
Xiao, Xianyong
Wang, Yang
Wu, Jun
Tematy:: system impedance
passive method
Thevenin equivalent
power system; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/1848954.pdf Link otwiera się w nowym oknie
Opis:: In recent years, assessing supply system impedance has become crucial due to the concerns on power quality and the proliferation of distributed generators. In this paper, a novel method is shown for passive measurement of system impedances using the gapless waveform data collected by a portable power quality monitoring device. This method improves the overall measurement accuracy through data regrouping. Compared with the traditional methods that use the consecutive measurement data directly, the proposed method regroups the data to find better candidates with less flotation on the system side. Simulation studies and extensive field tests have been conducted to verify the effectiveness of the proposed method. The results indicate that the proposed method can serve as a useful tool for impedance measurement tasks performed by utility companies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Assessing system impedance based on data regrouping
Autorzy:: Xu, Shuangting
Xiao, Xianyong
Wang, Yang
Wu, Jun
Tematy:: system impedance
passive method
Thevenin equivalent
power system; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/1848965.pdf Link otwiera się w nowym oknie
Opis:: In recent years, assessing supply system impedance has become crucial due to the concerns on power quality and the proliferation of distributed generators. In this paper, a novel method is shown for passive measurement of system impedances using the gapless waveform data collected by a portable power quality monitoring device. This method improves the overall measurement accuracy through data regrouping. Compared with the traditional methods that use the consecutive measurement data directly, the proposed method regroups the data to find better candidates with less flotation on the system side. Simulation studies and extensive field tests have been conducted to verify the effectiveness of the proposed method. The results indicate that the proposed method can serve as a useful tool for impedance measurement tasks performed by utility companies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Analysis of the neutral grounding modes influence on the reliability characteristics of local systems with renewable energy sources
Autorzy:: Ostapchuk, Oleksandr
Kuznetsov, Valeriy
Kruczek, Włodzimierz
Kuznetsov, Vitaliy
Tsyplenkov, Dmytro
Tematy:: electric networks
protection
reliability
ground failure current
electrical safety
system with isolated neutral
system with resonant grounding
system with low-impedance neutral grounding
sieć elektryczna
ochrona
niezawodność
bezpieczeństwo; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Powiązania:: https://bibliotekanauki.pl/articles/1840882.pdf Link otwiera się w nowym oknie
Opis:: When comparing the performance indicators of electrical networks with different types of neutral grounding, along with the fulfilment of the requirement to ensure reliability of power supply to consumers, serious attention is drawn to the main network parameters influencing the performance of power supply systems. Analysis of research and its results, reported above, on the influence of the neutral ground of power networks on the reliability and electrical safety conditions of the power supply systems as a whole, on the damage of distribution networks and electrical equipment as well as on the working capacity of relay protection devices, provides an opportunity to estimate each specific operation mode of the neutral and to develop recommendations aimed at strengthening the positive indicators of the corresponding modes. Other things being equal, reliability of power supply to electrical receivers or reliability of distribution networks is mainly determined by the damage to network elements and the performance of relay protection devices. The degree of influence of these factors on the reliability of distribution networks depends on the neutral mode, which in turn determines the level of internal overvoltages and the nature of transient processes at earth fault.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Power grid impedance tracking with uncertainty estimation using two stage weighted least squares
Autorzy:: Borkowski, D.
Barczentewicz, S.
Tematy:: power system
utility impedance tracking
uncertainty estimation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/220406.pdf Link otwiera się w nowym oknie
Opis:: The paper presents a new method for simultaneous tracking of varying grid impedance and its uncertainty bounds. Impedance tracking consists of two stages. In the first stage, the actual noise estimate is obtained from least squares (LS) residua. In the second stage, the noise covariance matrix is approximated with the use of residual information. Then weighted least squares (WLS) method is applied in order to estimate impedance and background voltage. Finally uncertainty bounds for impedance estimation are computed. The robustness of the method has been verified using simulated signals. The proposed method has been compared to sliding LS. The results have shown, that the method performs much better than the LS for all considered cases, even in the presence of significant background voltage variations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Integrated impedance scanner in selected biomeasurement applications - control circuit
Autorzy:: Przeniosło, Ł.
Walków, M.
Krzeszewska, S.
Pisarek, S.
Biedka, A.
Jaskuła, M.
Matias, D.
Penkala, K.
Tematy:: bioelectrical impedance
impedance spectroscopy
tissue
analysis of body composition
BIA
bioelectrical impedance analysis
impedance scanner
microprocessor system
SoC
simulation
impedancja bioelektryczna
spektroskopia impedancji
tkanki
analiza składu ciała
analiza impedancji bioelektrycznej
skaner impedancyjny
system mikroprocesorowy
symulacje; Pokaż więcej
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Powiązania:: https://bibliotekanauki.pl/articles/118374.pdf Link otwiera się w nowym oknie
Opis:: In the paper the results of preliminary experiments concerning bioelectrical impedance measurements using integrated impedance scanner AD5933 (Analog Devices) are described. Results of performed simulations are also presented. Design of a control circuit based on ARM microprocessor is described. Possible applications of the bioelectrical impedance spectroscopy method in measurements of selected characteristics of the human organism are discussed as well as plans for future development of dedicated, specialized equipment.
W pracy przedstawiono wyniki wstępnych eksperymentów dotyczących pomiarów impedancji bioelektrycznej przy użyciu zintegrowanego skanera AD5933. Zaprezentowano wyniki przeprowadzonych symulacji oraz konstrukcję układu sterowania w oparciu o mikroprocesor. Omówiono możliwe zastosowania tej metody spektroskopii impedancji bioelektrycznej w pomiarach wybranych cech ludzkiego organizmu, a także możliwości przyszłego rozwoju dedykowanego urządzenia specjalistycznego.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Simple Wide Frequency Range Impedance Meter Based on AD5933 Integrated Circuit
Autorzy:: Chabowski, K.
Piasecki, T.
Dzierka, A.
Nitsch, K.
Tematy:: impedance
converter
AD5933
system-on-a-chip
measurement; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221804.pdf Link otwiera się w nowym oknie
Opis:: As it contains elements of complete digital impedance meter, the AD5933 integrated circuit is an interesting solution for impedance measurements. However, its use for measurements in a wide range of impedances and frequencies requires an additional digital and analogue circuitry. This paper presents the design and performance of a simple impedance meter based on the AD5933 IC. Apart from the AD5933 IC it consists of a clock generator with a programmable prescaler, a novel DC offset canceller for the excitation signal based on peak detectors and a current to voltage converter with switchable conversion ratios. The authors proposed a simple method for choosing the measurement frequency to minimalize errors resulting from the spectral leakage and distortion caused by a lack of an anti-aliasing filter in the DDS generator. Additionally, a novel method for the AD5933 IC calibration was proposed. It consists in a mathematical compensation of the systematic error occurring in the argument of the value returned from the AD5933 IC as a result. The performance of the whole system is demonstrated in an exemplary measurement.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Evaluation of quality of heterogeneous mechanical systems using impedance method
Autorzy:: Volkovas, V.
Gulbinas, R.
Slavickas, E. S.
Tematy:: diagnostyka
jakość
impedancja
metoda
heterogeneous mechanical system
quality
impedance
diagnostics; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Powiązania:: https://bibliotekanauki.pl/articles/329300.pdf Link otwiera się w nowym oknie
Opis:: The paper analyzes methodology for investigation of dynamic characteristics of heterogeneous systems: honeycomb optical tables and pipelines with sediments, applying mechanical impedance. The developed methodology may be used to assess the quality of plate or cylindrical heterogeneous structures, according to the dynamic characteristics and parameters established in the methodology. It was shown that impedance characteristics are informative to determine some parameters of the quality of honeycomb optical tables and are correlated with the thickness of the pipe's inner sediment layer. Therefore it is possible to choose typical resonance frequencies and according to their changes, the decision about inner layer presence and its value can be made.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Impedance cardiography – Old method, new opportunities. Part II. Testing of cardiovascular response to various factors of work environment
Autorzy:: Siedlecka, Jadwiga
Siedlecki, Patryk
Bortkiewicz, Alicja
Tematy:: impedance cardiography
cardiovascular system
work environment
occupational stress
physical activity
drivers’ health; Pokaż więcej
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Powiązania:: https://bibliotekanauki.pl/articles/2177030.pdf Link otwiera się w nowym oknie
Opis:: Impedance cardiography seems to be a very good, although underappreciated diagnostic method. What may distinguish it from among the many research methods is the fact that it enables non-invasive monitoring of cardiac output, stroke volume and systemic vascular resistance. Holter recording of the hemodynamic parameters makes it possible to study them not only in stationary (hospital, outpatient clinic) conditions, but also during household or professional activities, e.g., during road vehicle driving. Assessment of the trends of changes in the circulatory system of the employee at work makes it possible to judge whether the type of work performed by the worker is well tolerated – whether it is not too hard or too stressful. This is important, therefore, impedance cardiography can be extensively used in occupational medicine. Provision of preventive care to workers according to current standards requires, on the one hand, the use of the latest diagnostic methods while, on the other hand, the methods must be inexpensive, because otherwise the employer would not be able or willing to pay the associated costs. Impedance cardiography meets those criteria; however, few data is available in literature worldwide on the use of this method in the research on the impact of occupational work on cardiovascular responses of the employees. This work reports the use of impedance cardiography in studies on the various aspects of work environment.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Sposoby nastawiania impedancyjnych blokad przeciwkołysaniowych stosowanych w zabezpieczeniach odległościowych
Autorzy:: Smolarczyk, A.
Tematy:: impedancyjna blokada przeciwkołysaniowa
kołysanie mocy
system elektroenergetyczny
zabezpieczenie
impedance
rocking lock
rocking power
power system
protection; Pokaż więcej
Wydawca:: ENERGA
Powiązania:: https://bibliotekanauki.pl/articles/397342.pdf Link otwiera się w nowym oknie
Opis:: W artykule opisano sposoby nastawiania impedancyjnych blokad przeciwkołysaniowych typu Z(t). Blokady tego typu są powszechnie wykorzystywane do blokowania działania stref zabezpieczeń odległościowych podczas kołysań mocy. Opisane zostały sposoby nastawiania podstawowych parametrów, do których należą: zasięgi rezystancyjne i reaktancyjne, nastawa timera związanego z pobudzeniem blokady i nastawa timera związanego z deblokadą (czas deblokady).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Stability and adaptability analysis of the traction power supply system with photovoltaic and energy storage under two access structures
Autorzy:: Wei, Chunyu
Li, Xin
Tematy:: energy storage system
impedance model
photovoltaic
railway power conditioner
stability analysis
traction power supply system; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59345884.pdf Link otwiera się w nowym oknie
Opis:: The integration of photovoltaic and the energy storage system into traction power supply systems under railway power conditioner (RPC) or voltage source converter (VSC) access structures changes the original pure AC system into a hybrid AC/DC system. At the same time, which access structure of photovoltaic and the energy storage system has higher system stability and which has better adaptability are rarely mentioned in the stability analysis of traction power supply systems with photovoltaic and the energy storage system. Firstly, in this paper, impedance models for the two types of access structures of photovoltaic and energy storage systems are established, and the port impedance characteristics and stability influencing factors are analyzed from the aspects of system parameters and controller parameters. Second, combining the two typical working conditions of PV and the ESS access traction power system, from the perspective of stability, the robustness of the two access structures under the influence of negative impedance characteristics and the adaptability of access are compared. Compared to traditional stability analysis methods, the GMPM (Gain Margin and Phase Margin) criterion employed in this paper integrates both the dynamic characteristics and frequency response of the system, making it particularly suitable for small-signal stability analysis. Keeping the rest of the conditions the same under two typical working conditions, the RPC access structure has higher system stability when the two access structures input and output 35kW of active power, respectively. Finally, the simulation results in the MATLAB/Simulink simulation platform also confirm the better adaptability of the RPC access structure.
Dostawca treści:: Biblioteka Nauki

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