During electric vehicle(EV)-assisted grid frequency modulation,inconsistent state of charge(SOC)among EVs can result in overcharging and discharging of the batteries,affecting the stability of the electrical system.As...During electric vehicle(EV)-assisted grid frequency modulation,inconsistent state of charge(SOC)among EVs can result in overcharging and discharging of the batteries,affecting the stability of the electrical system.As a solution,this paper proposes a priority-based frequency regulation strategy for EVs.Firstly,models for the primary and secondary frequency regulation of EV-assisted power grids are established.Secondly,a consensus algorithm is used to construct a distributed com-munication system for EVs.Target SOC values are used to obtain a local frequency regulation priori-ty list.The list is used in an optimal control plan allowing individual EVs to participate in frequency regulation.Finally,a simulation of this strategy under several scenarios is conducted.The results indicate that the strategy ensures uniform SOC among the participating group of EVs,thereby avoi-ding overcharging and discharging of their batteries.It also reduces frequency fluctuations in the electrical system,making the system more robust compared with the frequency regulation strategy that is not priority-based.展开更多
Based on the characteristic of AC-excited variable speed constant frequency(VSCF)wind power generation,the vector control technique was applied in a doubly fed induction generator(DFIG).Maximum wind energy or maximum ...Based on the characteristic of AC-excited variable speed constant frequency(VSCF)wind power generation,the vector control technique was applied in a doubly fed induction generator(DFIG).Maximum wind energy or maximum output power point can be tracked by decoupling control of active power and reactive power.The research result shows that the net power of generation system delivered to grid in maximum wind energy tracking mode is not the most.We presented a novel maximum power point tracking(MPPT)control strategy by analyzing the DFIG mathematic model and power relations which delivered the maximum power to the grid.The maximum power point could be tracked automatically without measuring wind speed in the control strategy and the control was independent of optimal turbine power curve,which had excellent dynamic and static performances and robustness.Simulation and experimental results testify the accuracy and validity of the control strategy.展开更多
Accurate grid frequency prediction is essential for the stable operation and optimized dispatch of modern power systems.However,efficiently identifying critical features that influence grid frequency prediction from h...Accurate grid frequency prediction is essential for the stable operation and optimized dispatch of modern power systems.However,efficiently identifying critical features that influence grid frequency prediction from highdimensional,complex power system data remains a significant challenge.To enhance the accuracy of grid frequency predictions,a feature selection method that integrates Bayesian Optimization(BO),LightGBM,and the Boruta algorithm(BO-LightGBM-Boruta)was proposed.The data collected under various fault scenarios from the New England 10-machine 39-bus test system were used as experimental samples to train the grid frequency prediction models and evaluate their predictive performance,thereby verifying the effectiveness and practical value of the proposed feature selection approach.The performance of the BO-LightGBM-Boruta method is compared with Lasso regression and Recursive Feature Elimination(RFE)under three prediction models:E3DLSTM,LSTM,and ConvLSTM.The results show that the BO-LightGBM-Boruta method provides significantly more accurate predictions than the other two feature selection approaches in grid frequency prediction tasks.Notably,the combination of the proposed method and E3D-LSTM,which achieves the highest accuracy across different fault conditions,demonstrates outstanding predictive performance.展开更多
This paper proposes a dual alternative iter-ation algorithm-based hierarchical MPC(DAMPC)strategy to realize frequency regulation control and active power allocation of wind-storage coupling system.The proposed DAMPC ...This paper proposes a dual alternative iter-ation algorithm-based hierarchical MPC(DAMPC)strategy to realize frequency regulation control and active power allocation of wind-storage coupling system.The proposed DAMPC strategy involves a top-level grid fre-quency model predictive control(FMPC)strategy and a bottom-level multi-objective model predictive control(MMPC)strategy.In the FMPC strategy,to improve the frequency regulation performance,the active power ref-erence of the wind-storage coupling system is generated by minimizing the frequency deviation,where the fre-quency reference is calculated by considering the active power deviation and its integral.In the MMPC strategy,the active power reference is optimally allocated to the wind turbine generators(WTGs)and battery energy storage system(BESS)by raising the minimum rotor speed,minimizing the pitch angle deviation and state of charge(SOC)deviation.To solve the multi-objective al-location optimization problem with high efficiency,a dual alternative iteration algorithm(DAIA)is proposed to update the global and local control vectors with the dual vector.Extensive simulations validate the effectiveness of the proposed DAMPC strategy in frequency regulation and active power allocation.展开更多
This paper proposes a grid synchronization control strategy for the grid-connected voltage source converters(VSCs)based on the voltage dynamics of the DC-link capacitor in the VSC.The voltage dynamics of the DC-link c...This paper proposes a grid synchronization control strategy for the grid-connected voltage source converters(VSCs)based on the voltage dynamics of the DC-link capacitor in the VSC.The voltage dynamics of the DC-link capacitor are used to regulate the frequency and phase angle of the inner potential of the VSC,synchronizing the VSC with grid.Firstly,in the proposed strategy,the active power regulation and grid synchronization of the VSC are combined,which are separated in the traditional control strategy.This can avoid the instability of the VSC in a weak grid with a low short circuit ratio(SCR),aroused by the dynamic interaction between the separated control loops in traditional control strategies.Secondly,the energy stored in the DC-link capacitor is directly coupled with the grid via the inner potential of the VSC,and the inertia characteristic is naturally featured in the inner potential by the proposed strategy.With the increase of the capacitance,the natural inertial response of the VSC is helpful to improve the grid frequency dynamic.Finally,simulation results are presented to validate the correctness and effectiveness of the proposed strategy in the enhancement of the grid frequency and voltage dynamic support capability.展开更多
基金Supported by the China Postdoctoral Science Foundation(No.2022M710039).
文摘During electric vehicle(EV)-assisted grid frequency modulation,inconsistent state of charge(SOC)among EVs can result in overcharging and discharging of the batteries,affecting the stability of the electrical system.As a solution,this paper proposes a priority-based frequency regulation strategy for EVs.Firstly,models for the primary and secondary frequency regulation of EV-assisted power grids are established.Secondly,a consensus algorithm is used to construct a distributed com-munication system for EVs.Target SOC values are used to obtain a local frequency regulation priori-ty list.The list is used in an optimal control plan allowing individual EVs to participate in frequency regulation.Finally,a simulation of this strategy under several scenarios is conducted.The results indicate that the strategy ensures uniform SOC among the participating group of EVs,thereby avoi-ding overcharging and discharging of their batteries.It also reduces frequency fluctuations in the electrical system,making the system more robust compared with the frequency regulation strategy that is not priority-based.
基金Funded by the National Natural Science Foundation of China(No.60974049)the Science and Technology Support Industrial Project of Jiangsu Province(No.BZ2008031,No.BE2008074,and No.BE2009090)+1 种基金the Nantong International Cooperative Project(No.W2009003)the Natural Science Foundation of Nantong University(No.08Z022 and No.08Z025).
文摘Based on the characteristic of AC-excited variable speed constant frequency(VSCF)wind power generation,the vector control technique was applied in a doubly fed induction generator(DFIG).Maximum wind energy or maximum output power point can be tracked by decoupling control of active power and reactive power.The research result shows that the net power of generation system delivered to grid in maximum wind energy tracking mode is not the most.We presented a novel maximum power point tracking(MPPT)control strategy by analyzing the DFIG mathematic model and power relations which delivered the maximum power to the grid.The maximum power point could be tracked automatically without measuring wind speed in the control strategy and the control was independent of optimal turbine power curve,which had excellent dynamic and static performances and robustness.Simulation and experimental results testify the accuracy and validity of the control strategy.
文摘Accurate grid frequency prediction is essential for the stable operation and optimized dispatch of modern power systems.However,efficiently identifying critical features that influence grid frequency prediction from highdimensional,complex power system data remains a significant challenge.To enhance the accuracy of grid frequency predictions,a feature selection method that integrates Bayesian Optimization(BO),LightGBM,and the Boruta algorithm(BO-LightGBM-Boruta)was proposed.The data collected under various fault scenarios from the New England 10-machine 39-bus test system were used as experimental samples to train the grid frequency prediction models and evaluate their predictive performance,thereby verifying the effectiveness and practical value of the proposed feature selection approach.The performance of the BO-LightGBM-Boruta method is compared with Lasso regression and Recursive Feature Elimination(RFE)under three prediction models:E3DLSTM,LSTM,and ConvLSTM.The results show that the BO-LightGBM-Boruta method provides significantly more accurate predictions than the other two feature selection approaches in grid frequency prediction tasks.Notably,the combination of the proposed method and E3D-LSTM,which achieves the highest accuracy across different fault conditions,demonstrates outstanding predictive performance.
文摘This paper proposes a dual alternative iter-ation algorithm-based hierarchical MPC(DAMPC)strategy to realize frequency regulation control and active power allocation of wind-storage coupling system.The proposed DAMPC strategy involves a top-level grid fre-quency model predictive control(FMPC)strategy and a bottom-level multi-objective model predictive control(MMPC)strategy.In the FMPC strategy,to improve the frequency regulation performance,the active power ref-erence of the wind-storage coupling system is generated by minimizing the frequency deviation,where the fre-quency reference is calculated by considering the active power deviation and its integral.In the MMPC strategy,the active power reference is optimally allocated to the wind turbine generators(WTGs)and battery energy storage system(BESS)by raising the minimum rotor speed,minimizing the pitch angle deviation and state of charge(SOC)deviation.To solve the multi-objective al-location optimization problem with high efficiency,a dual alternative iteration algorithm(DAIA)is proposed to update the global and local control vectors with the dual vector.Extensive simulations validate the effectiveness of the proposed DAMPC strategy in frequency regulation and active power allocation.
基金supported by Science and Technology Project of Yunnan Power Grid Co.,Ltd.(No.YNKJXM20222105)。
文摘This paper proposes a grid synchronization control strategy for the grid-connected voltage source converters(VSCs)based on the voltage dynamics of the DC-link capacitor in the VSC.The voltage dynamics of the DC-link capacitor are used to regulate the frequency and phase angle of the inner potential of the VSC,synchronizing the VSC with grid.Firstly,in the proposed strategy,the active power regulation and grid synchronization of the VSC are combined,which are separated in the traditional control strategy.This can avoid the instability of the VSC in a weak grid with a low short circuit ratio(SCR),aroused by the dynamic interaction between the separated control loops in traditional control strategies.Secondly,the energy stored in the DC-link capacitor is directly coupled with the grid via the inner potential of the VSC,and the inertia characteristic is naturally featured in the inner potential by the proposed strategy.With the increase of the capacitance,the natural inertial response of the VSC is helpful to improve the grid frequency dynamic.Finally,simulation results are presented to validate the correctness and effectiveness of the proposed strategy in the enhancement of the grid frequency and voltage dynamic support capability.
