A new hybrid wavelet-Kalman filter method for the estimation of dynamic system is developed, Using this method, the real-time multiscale estimation of the dynamic system is implemented, and the observation equation es...A new hybrid wavelet-Kalman filter method for the estimation of dynamic system is developed, Using this method, the real-time multiscale estimation of the dynamic system is implemented, and the observation equation established is for the object signal itself rather than its wavelet decomposition. The simulation results show that this method can be used to estimate the object's state of the stacked system, which is the foundation of multiscale data fusion; besides the performance of the new algorithm developed in the letter is almost optimal.展开更多
Aiming at the faults of some weak nodes in the concentrated solar power-photovoltaic(CSP-PV)hybrid power generation system,it is impossible to restore the transient voltage only relying on the reactive power regulatio...Aiming at the faults of some weak nodes in the concentrated solar power-photovoltaic(CSP-PV)hybrid power generation system,it is impossible to restore the transient voltage only relying on the reactive power regulation capability of the system itself.We propose a dynamic reactive power planning method suitable for CSP-PV hybrid power generation system.The method determines the installation node of the dynamic reactive power compensation device and its compensation capacity based on the reactive power adjustment capability of the system itself.The critical fault node is determined by the transient voltage stability recovery index,and the weak node of the system is initially determined.Based on this,the sensitivity index is used to determine the installation node of the dynamic reactive power compensation device.Dynamic reactive power planning optimization model is established with the lowest investment cost of dynamic reactive power compensation device and the improvement of system transient voltage stability.Furthermore,the component of the reactive power compensation node is optimized by particle swarm optimization based on differential evolution(DE-PSO).The simulation results of the example system show that compared with the dynamic position compensation device installation location optimization method,the proposed method can improve the transient voltage stability of the system under the same reactive power compensation cost.展开更多
A three-dimensional Direct numerical simulation(DNS)with complex chemistry was employed to examine the statistical behavior of turbulent kinetic energy(TKE)and enstrophy transport equations in hydrogen(Lewis number(Le...A three-dimensional Direct numerical simulation(DNS)with complex chemistry was employed to examine the statistical behavior of turbulent kinetic energy(TKE)and enstrophy transport equations in hydrogen(Lewis number(Le)≈0.4)and dodecane(Le≈4.2)flames.The Karlovitz(Ka)numbers ranged from 4 to 150,involving both the thin and broken reaction zones.Budget analyses of TKE and enstrophy transport equations are performed,and scaling terms in the literature are re-examined.Similar to thin reaction zone flames,viscous dissipation term appears to be the most important term in the TKE balance,while viscous dissipation and vortex-stretching terms are the dominant terms in the enstrophy transport equation at high Ka number.The velocity-pressure gradient and the mean velocity dilatation in the TKE transport equation and the dilatation term in enstrophy budget are found to be affected by the Le.Modified scaling estimations for those terms affected by Le are proposed in this work to account for the Le effects spanning different combustion regimes.This work confirmed that Kolmogorov’s first hypothesis is not valid for low Ka number flames investigated in this study,where the vortex stretching and viscous dissipation terms cannot be scaled with local dissipation and viscosity.At sufficiently high Ka number flames,the vorticity can be scaled with the Kolmogorov time scale,and the mean enstrophy value approaches homogeneous,isotropic,non-reacting turbulence flow,but lower Le fuels require much higher Ka number to achieve that.展开更多
基金Supported by National Natural Science Foundation of China(No.60434020, 60374020)International Cooperation Item of Henan(No.0446650006)Henan Outstanding Youth Science Fund(No.0312001900)
文摘A new hybrid wavelet-Kalman filter method for the estimation of dynamic system is developed, Using this method, the real-time multiscale estimation of the dynamic system is implemented, and the observation equation established is for the object signal itself rather than its wavelet decomposition. The simulation results show that this method can be used to estimate the object's state of the stacked system, which is the foundation of multiscale data fusion; besides the performance of the new algorithm developed in the letter is almost optimal.
基金Science and Technology Projects of State Grid Corporation of China(No.SGGSKY00FJJS1800140)。
文摘Aiming at the faults of some weak nodes in the concentrated solar power-photovoltaic(CSP-PV)hybrid power generation system,it is impossible to restore the transient voltage only relying on the reactive power regulation capability of the system itself.We propose a dynamic reactive power planning method suitable for CSP-PV hybrid power generation system.The method determines the installation node of the dynamic reactive power compensation device and its compensation capacity based on the reactive power adjustment capability of the system itself.The critical fault node is determined by the transient voltage stability recovery index,and the weak node of the system is initially determined.Based on this,the sensitivity index is used to determine the installation node of the dynamic reactive power compensation device.Dynamic reactive power planning optimization model is established with the lowest investment cost of dynamic reactive power compensation device and the improvement of system transient voltage stability.Furthermore,the component of the reactive power compensation node is optimized by particle swarm optimization based on differential evolution(DE-PSO).The simulation results of the example system show that compared with the dynamic position compensation device installation location optimization method,the proposed method can improve the transient voltage stability of the system under the same reactive power compensation cost.
基金supported by the National Natural Science Foundation of China(Grant Nos.91752201 and 11672123)Shenzhen Science and Technology Program(Grant Nos.JCYJ20170412151759222,JCYJ20180302173952945,and KQTD20180411143441009)+1 种基金Department of Science and Technology of Guangdong Province(Grant No.2019B21203001)Project No.LCH-2019011 under the Joint Program of Shenzhen Clean Energy Research Institute and SUSTech through contract CERI-KY-2019-003.
文摘A three-dimensional Direct numerical simulation(DNS)with complex chemistry was employed to examine the statistical behavior of turbulent kinetic energy(TKE)and enstrophy transport equations in hydrogen(Lewis number(Le)≈0.4)and dodecane(Le≈4.2)flames.The Karlovitz(Ka)numbers ranged from 4 to 150,involving both the thin and broken reaction zones.Budget analyses of TKE and enstrophy transport equations are performed,and scaling terms in the literature are re-examined.Similar to thin reaction zone flames,viscous dissipation term appears to be the most important term in the TKE balance,while viscous dissipation and vortex-stretching terms are the dominant terms in the enstrophy transport equation at high Ka number.The velocity-pressure gradient and the mean velocity dilatation in the TKE transport equation and the dilatation term in enstrophy budget are found to be affected by the Le.Modified scaling estimations for those terms affected by Le are proposed in this work to account for the Le effects spanning different combustion regimes.This work confirmed that Kolmogorov’s first hypothesis is not valid for low Ka number flames investigated in this study,where the vortex stretching and viscous dissipation terms cannot be scaled with local dissipation and viscosity.At sufficiently high Ka number flames,the vorticity can be scaled with the Kolmogorov time scale,and the mean enstrophy value approaches homogeneous,isotropic,non-reacting turbulence flow,but lower Le fuels require much higher Ka number to achieve that.
