Probability distribution of wind power volatility based on the moving average method and improved nonparametric kernel density estimation

In the process of large-scale,grid-connected wind power operations,it is important to establish an accurate probability distribution model for wind farm fluctuations.In this study,a wind power fluctuation modeling method is proposed based on the method of moving average and adaptive nonparametric kernel density estimation(NPKDE)method.Firstly,the method of moving average is used to reduce the fluctuation of the sampling wind power component,and the probability characteristics of the modeling are then determined based on the NPKDE.Secondly,the model is improved adaptively,and is then solved by using constraint-order optimization.The simulation results show that this method has a better accuracy and applicability compared with the modeling method based on traditional parameter estimation,and solves the local adaptation problem of traditional NPKDE.

Analysis on the fault characteristics of three-phase short-circuit for half-wavelength AC transmission lines

Half-wavelength AC transmission(HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the system power frequency. It is very important for the construction and operation of HWACT to analyze its fault features and corresponding protection technology. In this paper, the steady-state voltage and current characteristics of the bus bar and fault point and the steady-state overvoltage distribution along the line will be analyzed when a three-phase symmetrical short-circuit fault occurs on an HWACT line. On this basis, the threephase fault characteristics for longer transmission lines are also studied.

DMD-based hyperspectra I microscopy with flexible multiline parallel scanning

As one of the most common hyperspearal microscopy(HSM)techniques,line-scanning HSM is currently utilized in many fields.However,its scanning efficiency is still considered to be inadequate since many biological and chemical processes occur too rapidly to be captured.Accordingly,in this work,a digital micromirror device(DMD)based on microelectromechanical systems(MEMS)is utilized to demonstrate a flexible multiline scanning HSM system.To the best of our knowledge,this is the first line-scanning HSM system in which the number of scanning lines N can be tuned by simply changing the DMD's parallel scanning units according to diverse applications.This brilliant strategy of effortless adjustability relies only on on-chip scanning methods and totally exploits the benefits of parallelization,aiming to achieve nearly an A/-time improvement in the detection efficiency and an N-time decrease in the scanning time and data volume compared with the single-line method under the same operating conditions.To validate this,we selected a few samples of different spectral wavebands to perform reflection imaging,transmission imaging,and fluorescence imaging with varying numbers of scanning lines.The results show the great potential of our DMD-based HSM system for the rapid development of cellular biology,material analysis,and so on.In addition,its on-chip scanning process eliminates the inherent microscopic architecture,making the whole system compact,lightweight,portable,and not subject to site constraints.