The GFL-GFM hybrid wind farm (HWF) combines the voltage source control advantages of grid-forming (GFM) wind turbines (WTs) with the current source control advantages of grid-following (GFL) wind turbines. It becomes ...
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The GFL-GFM hybrid wind farm (HWF) combines the voltage source control advantages of grid-forming (GFM) wind turbines (WTs) with the current source control advantages of grid-following (GFL) wind turbines. It becomes a new type of large-scale grid-connected wind power generation. In this paper, we propose an HWF frequency-voltage active support based on GFL and GFM hierarchical subgroup control. It aims to realize the support of active power and reactive power under the premise of ensuring system stability. The strategy consists of the determination of the control objectives of the GFM-GFL subgroups, the distributed control (DC) of the GFM-GFL subgroups, and the adaptive control and switching of each unit of the GFM and GFL groups. The GFM-group maintains the grid-connected voltage stability and the GFL-group exhausts the active support. DC at the group level and adaptive control at the unit level are included under the hierarchy of the respective objectives. Finally, a GFL-GFM HWF model is established on the MATLAB/Simulink platform, and the simulation verifies that the proposed strategy can realize the enhancement of the frequency-voltage support capability of the HWF under the premise of grid-connected stability.
Acoustic signals contain rich discharge *** this study,the acoustic signal characteristics of transient glow,spark,and glow discharges generated through DC pin–pin discharge were *** signals were analyzed in the time...
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Acoustic signals contain rich discharge *** this study,the acoustic signal characteristics of transient glow,spark,and glow discharges generated through DC pin–pin discharge were *** signals were analyzed in the time,frequency,and time–frequency domains,and the correlation between the electric and the acoustic signal was studied *** results show that glow discharge does not produce measurable sound *** the other modes,with a decrease in the discharge gap,the amplitude of the acoustic signal increases sharply with mode transformation,the short-time average energy becomes higher,and the frequency components are more ***,the current pulse and sound pressure pulse have a one-to-one relationship in the transient glow and spark regimes,and they are positively correlated in amplitude.A brief theoretical analysis of the mechanism of plasma sound and the trends of signals in different modes is ***,the change in the discharge energy is closely related to the sound generation of the plasma.
The output of new energy represented by wind power and photovoltaic power features volatility and randomness. It is a practical approach to use the guaranteed rate with statistical characteristics to analyze the outpu...
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The output of new energy represented by wind power and photovoltaic power features volatility and randomness. It is a practical approach to use the guaranteed rate with statistical characteristics to analyze the output coefficient of new energy. However, there is a lack of analysis and demonstration on the value of the new energy output guaranteed rate. To solve this problem, a selection method for the new energy output guaranteed rate considering optimal energy storage configuration is proposed. First, the influence of the new energy output guaranteed rate on the new energy output coefficient is analyzed. Secondly, with the goal of minimizing the comprehensive costs, an optimal configuration model of energy storage based on the output guaranteed rate of new energy is constructed, and particle swarm optimization is used for the optimization solution. Then, according to the optimal energy storage configuration results under different guaranteed rates, a reasonable new energy output guaranteed rate is determined by maximizing the comprehensive benefits obtained from energy storage. Finally, an example applied to the power grid in an area of Guangdong in Southern China is provided to illustrate the effectiveness of the proposed method.
An externally generated resonant magnetic perturbation can induce complex non-ideal MHD responses in their resonant *** have studied the plasma responses using Fitzpatrick's improved two-fluid model and program **...
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An externally generated resonant magnetic perturbation can induce complex non-ideal MHD responses in their resonant *** have studied the plasma responses using Fitzpatrick's improved two-fluid model and program *** calculated the error field penetration threshold for *** addition,we find that the island width increases slightly as the error field amplitude increases when the error field amplitude is below the critical penetration ***,the island width suddenly jumps to a large value because the shielding effect of the plasma against the error field disappears after the *** scanning the natural mode frequency,we find that the shielding effect of the plasma decreases as the natural mode frequency ***,we obtain the m/n=2/1 penetration threshold scaling on density and temperature.
Generation of atmospheric pressure homogeneous air plasma in a large gap(>4 mm)is a *** this study,an atmospheric pressure homogeneous air plasma generated in a gap up to 10 mm is reported,which is based on a three...
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Generation of atmospheric pressure homogeneous air plasma in a large gap(>4 mm)is a *** this study,an atmospheric pressure homogeneous air plasma generated in a gap up to 10 mm is reported,which is based on a three-electrode configuration,where a high-voltage(HV)electrode and a middle electrode form a surface dielectric barrier discharge(S-DBD),and together with the ground electrode form the main volume ***-speed photographs confirm that the discharge in the main gap is *** gas temperature of the plasma estimated from the N_(2)(C^(3)∏_(u)-B^(3)∏_(g))(Δv=-2)emission is about 320 K,which is close to room temperature.A detailed analysis shows that the discharge ignited between the HV electrode and the middle electrode is serving as an electron source,and the electrons deposited on the dielectric plate are due to the S-DBD along with the applied voltage generating a driving force,which results in a high concentration of seed electrons in the main gap and induces the homogeneous *** analysis shows that the electric field in the main gap is only about18.45 k V·cm^(-1),which is much lower than the typical breakdown electric field of 30 k V·cm^(-1)for atmospheric pressure air discharge.
Inland all-electric ship is receiving more and more attention due to its advantages in terms of low carbon, energy conservation, and flexibility in operation mode. However, its extensive promotion and application are ...
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Fossil fuel depletion and environmental pollution problems promote development of renewable energy(RE)*** increasing penetration of RE,operation security and economy of power systems(PS)are greatly impacted by fluctua...
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Fossil fuel depletion and environmental pollution problems promote development of renewable energy(RE)*** increasing penetration of RE,operation security and economy of power systems(PS)are greatly impacted by fluctuation and intermittence of renewable *** this paper,information gap decision theory(IGDT)is adapted to handle uncertainty of wind power *** on conventional IGDT method,linear regulation strategy(LRS)and robust linear optimization(RLO)method are integrated to reformulate the model for rigorously considering security *** a robustness assessment method based on hybrid RLO-IGDT approach is proposed for analyzing robustness and economic performance of ***,a risk-averse linearization method is adapted to convert the proposed assessment model into a mixed integer linear programming(MILP)problem for convenient optimization without robustness ***,results of case studies validate superiority of proposed method in guaranteeing operation security rigorously and effectiveness in assessment of RSR for PS without *** Terms-Hybrid RLO-IGDT approach,information gap decision theory(IGDT),operation security,robustness assessment,robustness security region(RSR).
Sulfide-based all-solid-state lithium metal batteries(ASSLMBs)have received extensive attention due to their high energy density and high safety,while the poor interface stability between sulfide electrolyte and lithi...
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Sulfide-based all-solid-state lithium metal batteries(ASSLMBs)have received extensive attention due to their high energy density and high safety,while the poor interface stability between sulfide electrolyte and lithium metal anode limits their ***,a hybrid SEI(LICl/Li F/Li Zn)was constructed at the interface between Li_(5.5)PS_(4.5)Cl_(1.5)sulfide electrolyte and lithium *** Li Cl and Li F interface phases with high interface energy effectively induce the uniform deposition of Li^(+)and reduce the overpotential of Li^(+)deposition,while the Li Zn alloy interface phase accelerates the diffusion of lithium *** synergistic effect of the above functional interface phases inhibits the growth of lithium dendrites and stabilizes the interface between the sulfide electrolyte and lithium *** hybrid SEI strategy exhibits excellent electrochemical performance on symmetric batteries and all-solid-state *** symmetrical cell exhibits stable cycling performance over long duration over 500 h at 1.0 mA cm^(-2).Moreover,the LiNbO_(3)@NCM712/Li_(5.5)PS_(4.5)Cl_(1.5)/Li-10%Zn F_(2)battery exhibits excellent cycle stability at a high rate of 0.5 C,with a capacity retention rate of 76.4%after 350 cycles.
Better torque performance and higher reliability have long been the focus of research for slotted limited-angle torque motors(LATMs),which are primarily used to position first-stage valves in electrohydraulic *** pape...
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Better torque performance and higher reliability have long been the focus of research for slotted limited-angle torque motors(LATMs),which are primarily used to position first-stage valves in electrohydraulic *** paper presents a high reliability axial-flux slotted LATM with quasi-Halbach array for torque performance improvement including constant torque range(CTR)and output ***,the structure with two sets of windings and the operation principle of the proposed slotted LATM is ***,a brief design procedure is presented,the structure selections of open slot and double-stator single-rotor(DSSR)interior rotor with surface mounted quasi-Halbach permanent magnet(PM)array are illustrated,and the geometric parameters are optimized to obtain the optimal design of the proposed slotted ***,3-D finite-element method(FEM)is employed to compare the proposed slotted LATM with the conventional surface mounted PM slotted LATM in terms of cogging torque,no-load back EMF,and output torque,and the results show that the proposed LATM with quasi-Halbach array has a 10%improvement in output torque and a 25%improvement in ***,the flux linkages and torque performance of the two sets of windings under various conditions verify good magnetic ***,prototypes of two different rotor types are manufactured and a series of experiments are performed to validate the analysis.
Aiming at the problem that the time series forecasting method will produce a certain degree of lag due to its series autocorrelation, the multivariate equivalent ice thickness prediction using meteorological data as t...
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