Cobalt-free oxides GdxBal-xFeO3-σas（0.01 _〈 x _〈 0.1 ） were achieved by a solid state reaction method. It is found that GdxBal-xFeO3-σas（0.025 _〈 x _〈 0.1） exhibits the cubic perovskite structure. Among GdxB...Cobalt-free oxides GdxBal-xFeO3-σas（0.01 _〈 x _〈 0.1 ） were achieved by a solid state reaction method. It is found that GdxBal-xFeO3-σas（0.025 _〈 x _〈 0.1） exhibits the cubic perovskite structure. Among GdxBal-xFeO3-σas （0.025 -〈 x -〈 0.1 ）, the GdxBal-xFeO3-σas （GBF2.5） membrane shows the outstanding phase structure stability and the highest oxygen permeation, which can reach 1.44 ml. cm- 2. rain- 1 at 950 ℃ under air/He oxygen partial pressure gradient. The GBF2.5 membrane was successfully operated for more than 100 h at 800 ℃ and the oxygen permeation flux through the membrane is 0.62 ml. cm- 2. rain- 1. After 100 h oxygen permeation experiment at 800℃, X-ray diffraction （XRD） and energy dispersive X-ray spectrometer （EDXS） demonstrate that the GBF2.5 exhibits phase structure stability even at intermediate temoerature.展开更多
The increased level of penetration of wind generators into modern power system has significant effect on network operation. The time varying nature of wind speed has significant effect on performance of wind generator...The increased level of penetration of wind generators into modern power system has significant effect on network operation. The time varying nature of wind speed has significant effect on performance of wind generator, therefore efficient mechanism for stabilizing the output of the wind generator is very much needed. Self-excited induction generators （SEIG） already existing in the network are sensitive to wind speeds. In this paper, a new method for voltage control of SEIG utilizing reactive power enhancing capabilities of doubly-fed induction generator （DFIG） is simulated and its effect on the network is analyzed for varying wind speeds. The choice of placing DFIG adjacent to SEIG or at another bus is also addressed in this paper with simulation results. The results show that this method of utilizing the reactive power capabilities of DFIG enhances voltage stability of SEIG as well as system stability.展开更多
基金Supported by the National Science Fund for Distinguished Young Scholars of China(21225625)the National Natural Science Foundation of China(21176087)the Specialized Research Fund for the Doctoral Program of Higher Education(20110172110013)
文摘Cobalt-free oxides GdxBal-xFeO3-σas（0.01 _〈 x _〈 0.1 ） were achieved by a solid state reaction method. It is found that GdxBal-xFeO3-σas（0.025 _〈 x _〈 0.1） exhibits the cubic perovskite structure. Among GdxBal-xFeO3-σas （0.025 -〈 x -〈 0.1 ）, the GdxBal-xFeO3-σas （GBF2.5） membrane shows the outstanding phase structure stability and the highest oxygen permeation, which can reach 1.44 ml. cm- 2. rain- 1 at 950 ℃ under air/He oxygen partial pressure gradient. The GBF2.5 membrane was successfully operated for more than 100 h at 800 ℃ and the oxygen permeation flux through the membrane is 0.62 ml. cm- 2. rain- 1. After 100 h oxygen permeation experiment at 800℃, X-ray diffraction （XRD） and energy dispersive X-ray spectrometer （EDXS） demonstrate that the GBF2.5 exhibits phase structure stability even at intermediate temoerature.
文摘The increased level of penetration of wind generators into modern power system has significant effect on network operation. The time varying nature of wind speed has significant effect on performance of wind generator, therefore efficient mechanism for stabilizing the output of the wind generator is very much needed. Self-excited induction generators （SEIG） already existing in the network are sensitive to wind speeds. In this paper, a new method for voltage control of SEIG utilizing reactive power enhancing capabilities of doubly-fed induction generator （DFIG） is simulated and its effect on the network is analyzed for varying wind speeds. The choice of placing DFIG adjacent to SEIG or at another bus is also addressed in this paper with simulation results. The results show that this method of utilizing the reactive power capabilities of DFIG enhances voltage stability of SEIG as well as system stability.
