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PL
W artykule przedstawiono wyniki zastosowania okna czasowego o płaskiej charakterystyce amplitudowej do obliczania fazora w sieciach elektroenergetycznych. Otrzymane wyniki porównano do wyników uzyskanych dla okna prostokątnego i okna Hanna. Do określenia właściwości porównywanych metod obliczeniowych wykorzystano niektóre z testów zgodności standardu IEEE Standard for Synchrophasor Measurements for Power Systems, oraz zdefiniowane tam błędy TVE (total vector error) i FE (frequency error). Otrzymane wyniki wskazują, że okna o płaskiej charakterystyce widmowej pozwalają istotnie poprawić dokładność estymacji fazora zwłaszcza w stanie ustalonym.
EN
This paper presents results of direct phasor estimation by DFT with application of flat-top windows. Results obtained with rectangular window and Hann window are also presented for comparison. The quality of the phasor estimation is evaluated by TVE (total vector error) and FE (frequency error) as defined in the IEEE Standard for Synchrophasor Measurements for Power Systems. The application of flat-top windows resulted in significant reduction of TVE in steadystate compliance tests. For actual frequency fin=50±2,5 Hz maximum TVE was reduced about 30 times as compare to Hann window. The smallest maximum FE errors were also obtained for flat-top window. In dynamic compliance tests flat-top windows performed only slightly better than Hann window and rectangular window in frequency estimation, and maximum TVE error is even slightly higher than for rectangular window for modulating frequency above 2,5 Hz. Straightforward computation of the phasor based on one DFT bin has computational complexity N. Application of FFT algorithms is not advised, because only one DFT bin is required. The phasor may be computed on sample by sample basis by discrete time convolution with FIR filter. In that case reporting frequency is the same as the sampling frequency of the signal.
PL
Omówiono definicje synchronicznego pomiaru fazorów określoną przez normę IEEE C37.118 w zakresie klas urządzeń realizujących funkcję pomiarową w stanach ustalonych.
EN
The paper discusses definition of synchronous measurement of phasors as specified by IEEE C37.118 standard in the scope of classes of equipment that carry out measurement function in steady state.
3
Content available Use of Phasors in Nonlinear Analysis
EN
In this paper, the well-known method of phasor analysis of linear ac circuits is extended in a rigorous mathematical way to nonlinear analysis. This fills the lack of such a theory in the literature. The results derived enable carrying out the needed corrections of some results published recently that regard harmonic distortion analysis of weakly nonlinear circuits.
EN
Increasing deniands for quality and reliability of electrical supply with rising complexity of electrical networks put emphasis on possibility to monitor and foresee behavior of these networks. One of the main aims of this monitoring is to prevent events that may cause failure or evcn datnages of the transmission network or the user side. This is the reason why units for synchrophasor measurements getting increased attention these days. Main function of PMU units is to measure and report the network status in predefincd locations. PMU features in terms of evaluation and reporting dcscribe the standard IEEE C37.188. As well as measurement, very important part is also a data transfer to higher systems. This article de- seribes standard IEEE C37.118 in terms of data frames transfer and structure of these frames between PMU and PDC systems. Part of this work also describes PMUGen software which simulate PMU data stream and cnables to study transmission in PMU networks. This software is dcveloped in graphical environment LabVIEW. This software enables creation of virtual PMU units without using of any spccial hardware and will be used as a tool for teaching students interested in this field.
PL
W nawiązaniu do tematyki obrad ubiegłorocznego Kolokwium Komitetu Studiów CIGRE B5 w Korei artykuł przedstawia problemy związane z wyznaczaniem fazorów w stanach dynamicznych oraz zagadnienia dotyczące testowania urządzeń do pomiaru fazorów. Testowanie przedstawiono w odniesieniu do wymagań wynikających z normy PC37.118, a dotyczących algorytmu obliczeniowego, sposobu obliczania błędu pomiaru fazora, sposobu synchronizacji czasu oraz protokołu przesyłania danych z PMU do koncentratora danych i systemu nadrzędnego. Artykuł recenzowany.
EN
In this paper both estimation synchrophasor problems in dynamic states and testing of phasor measurement units (PMUs) are described. Testing issues are presented with respect to IEEE-PC37.118 standard requirements including: estimation algorithms, phasor calculation error, time synchronization and protocol used to transmit data from a PMU to data concentrator and/or the master system.
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