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1

The best scheduling model of wind power pumped-storage power station based on improved harmony search algorithm

Zeng M., Chen L., Ma M., Xue S., Cheng M.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

74--77

EN

For the problem of integrating wind power in a large scale, constructing an objective function which minimize the total production cost of the pumped storage and thermal power unit. Improved harmony search algorithm with examples are applied in solving the objective function,and the case analysis the change of the operation cost of wind storage system and greenhouse gas emission with different power demand and wind speed forecasting scenes. The results show that the increase of wind power installed capacity can reduce the operation cost of wind storage system and reduce greenhouse gas emission. At the same time,it also can effectively smooth wind power output and lower the volatility of the wind power integration.

PL

Artykuł dotyczy zagadnienia tworzenia dużych ferm wiatrowych i kontroli kosztów wytwarzania energii. Proponowany algorytm minimalizacji strat, poddaje analizie czynniki taki jak koszty magazynowania energii, emisja gazów cieplarnianych przy różnym stopniu zapotrzebowania energetycznego i prędkości wiatru. Przedstawiono wyniki badań oraz wnioski.

2

Short-term Wind Speed Prediction Based on Grey System Theory Model in the Region of China

Zhang J., Cheng M., Cai X.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7a

67-71

EN

Short-term wind speed forecasting is useful for power system to regulate power dispatching plan, decrease reserve power needed and increase the reliability of system. The method of the short-term wind speed prediction is proposed in this paper. The data of wind speed in Dafeng, Jiangsu Province of China is predicted by the model combined with the grey system theory (GST). A grey system model consists of accumulating generation operation of original wind speed sequence data, data processing and wind speed forecasting. The hourly mean wind speed data at 85 meters above ground level of one year is generated by meteorological tower operated by the local bureau of meteorology. In this paper, the hourly average wind speed measured every an hour of 24 hours on Jan.1st, 2008 are the initial dataset for predicting. The result of wind speed is predicted by the grey system theory model with 0.14% of minimum relative percentage error (MRPE) and 7.22% of maximum mean absolute percentage error. The wind speed predicted values are given by the graphs and tables, which can be used easily for assessment of short-term wind energy in the different regions within China.

PL

W artykule zaproponowano metodę krótkookresowego prognozowania szybkości wiatru. Do prognozowania zastosowano teorię GST (Grey system theory). System składa się z panelu zbierania i przechowywania danych, przetwarzania danych i prognozowania. Zbierane są dane prędkości wiatru 85 metrów nad powierzchnią ziemi.

3

Investigation of Transient Torque during a Power System Fault in Wind Power Turbines Having a DFIG and Crowbar Circuit

Cheng M., Cai X., Wu G.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 11

245-250

EN

To study the influence of power system voltage drop on the doubly-fed induction generator (DIFG) shaft, this paper analyzes the electromagnetic torque change of the DFIG through approximated analytical expression of the stator fault current and rotor fault current obtained by the superposition between transient current based on vector method and steady-state current based on equivalent circuit method, and then the DFIG torque change situations under the following circumstances: the three-phase symmetrical voltage dip of stator terminal, the converter of the rotor side is cut off, and the crowbar circuit is put into the operation, will be analyzed through the method. Furthermore, on the basis of theoretical analysis, a 2MW DFIG model is established by PSCAD, and the simulation results validate that the torque changes of the DFIG shaft could be analyzed by the expression of the DFIG torque during the grid voltage drops through the superposition of the transient current and steadystate current. At last, the optimizing value of the crowbar resistance is given.

PL

W artykule analizuje się zmiany momentu elektromagnetycznego podwójnie zasilanego generator indukcyjnego DFIG poprzez ocenę prądów wirnika i stojana otrzymaną przez superpozycję prądów przejściowych (metoda wektorowa) i prądu stanu ustalonego (metoda obwodów zastępczych). Badania symulacyjne potwierdziły słuszność metody.