This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surf...This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surface wave radar(HFSWR) systems. The analysis shows that the tidal current pattern in the southwestern Taiwan Strait is primarily semi-diurnal and influenced significantly by shallow water constituents. The spatial distribution of tidal current ellipses of M2 is probably affected by the interaction between two different systems of tide wave, one from the northern mouth of Taiwan Strait and the other from the Bashi Channel. The directions of the major axes of M2 tidal current ellipses coincide roughly with the axis of the Taiwan Strait. The spatial distribution of the magnitudes of the probable maximum current velocity(PMCS) shows gradual increase of the velocity from northeast to southwest, which is in accordance with the spatial distribution of the measured maximum current velocity(MMCS). The directions of the residual currents are in accordance with the direction of the prevailing monsoon wind at the Taiwan Strait and the direction of the Taiwan warm current during summer. The bathymetry also shows a significant effect on the spatial distribution characteristics of tidal currents.展开更多
Bulk power systems show increasingly significant frequency spatial distribution characteristics(FSDCs),leading to a huge difference in the frequency response between regions.Existing uniform-frequency models based on ...Bulk power systems show increasingly significant frequency spatial distribution characteristics(FSDCs),leading to a huge difference in the frequency response between regions.Existing uniform-frequency models based on analytical methods are no longer applicable.This paper develops a reduced-order bus frequency response(BFR)model to preserve the FSDC and describe the frequency response of all buses.Its mathematical equation is proved to be isomorphic to the forced vibration of a mass-spring-damper system,and the closed-form solution(CFS)of the BFR model is derived by the modal analysis method and forced decoupling method in vibration mechanics.The correla tion between its mathematical equation and the state equation for small-signal stability analysis is discussed,and related pa rameters in the CFS are defined by the eigen-analysis method without any additional devices or tools.Case studies show that the proposed reduced-order BFR model and its CFS can im prove the solution accuracy while keeping the solution speed within milliseconds,which can preserve the significant FSDC of bulk power systems and represent a normalized mathematical description of distinct-frequency models.展开更多
基金supported by the National High Technology Research and Development Program (‘863’ Program) of China under contract No. 2012AA091701the Fundamental Research Fund for the Central University of China under the contract No. 2012212020211
文摘This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surface wave radar(HFSWR) systems. The analysis shows that the tidal current pattern in the southwestern Taiwan Strait is primarily semi-diurnal and influenced significantly by shallow water constituents. The spatial distribution of tidal current ellipses of M2 is probably affected by the interaction between two different systems of tide wave, one from the northern mouth of Taiwan Strait and the other from the Bashi Channel. The directions of the major axes of M2 tidal current ellipses coincide roughly with the axis of the Taiwan Strait. The spatial distribution of the magnitudes of the probable maximum current velocity(PMCS) shows gradual increase of the velocity from northeast to southwest, which is in accordance with the spatial distribution of the measured maximum current velocity(MMCS). The directions of the residual currents are in accordance with the direction of the prevailing monsoon wind at the Taiwan Strait and the direction of the Taiwan warm current during summer. The bathymetry also shows a significant effect on the spatial distribution characteristics of tidal currents.
基金supported in part by the National Natural Science Foundation of China(No.U22A20223).
文摘Bulk power systems show increasingly significant frequency spatial distribution characteristics(FSDCs),leading to a huge difference in the frequency response between regions.Existing uniform-frequency models based on analytical methods are no longer applicable.This paper develops a reduced-order bus frequency response(BFR)model to preserve the FSDC and describe the frequency response of all buses.Its mathematical equation is proved to be isomorphic to the forced vibration of a mass-spring-damper system,and the closed-form solution(CFS)of the BFR model is derived by the modal analysis method and forced decoupling method in vibration mechanics.The correla tion between its mathematical equation and the state equation for small-signal stability analysis is discussed,and related pa rameters in the CFS are defined by the eigen-analysis method without any additional devices or tools.Case studies show that the proposed reduced-order BFR model and its CFS can im prove the solution accuracy while keeping the solution speed within milliseconds,which can preserve the significant FSDC of bulk power systems and represent a normalized mathematical description of distinct-frequency models.
