Research On Electric Load Online Modeling Based On Target Tracking

As a fundamental part of power systems,electric load modeling has met a new challenge with the rapid development of power grids.Aiming at the problem of time-varying and discrete nature of electric load,a new idea of online load modeling based on target tracking is proposed in this paper,and its parameters and modes is tracing online respectively.The main work is as follows:(1)Aiming at the time-varying nature,an online load modeling method based on UKPF is proposed from the perspective of parameter tracking.After a commonly used exponential dynamic load model structure is selected,UKPF is used to estimate its parameters online.In this way,the parameters of the dynamic load model can be adjusted online according to the measured data,and the real-time load characteristics are tracked effectively.The measurements from the digital simulation platform and the actual power systems are used to test the effectiveness of the proposed method,respectively.The results provided by the proposed online parameter identification method is accurate,the real-time change load characteristics of the actual power system also can be described precisely.(2)To further describe the nonlinear discrete change of online electric load,an online modeling method based on interactive multiple model(IMM)algorithm is proposed from the perspective of mode tracking,where sub-model and online model is researched respectively.In the establishment of the sub-model,an improved artificial bee colony(ABC)algorithm is proposed and used to identify its parameters.An update replacement strategy of the worst nectar group is presented,which is introducing the main principle of shuffled frog-leaping algorithm(SFLA)and combining with the optimization feature of ABC algorithm.From the strategy,the overall fitness of bee colony is increasing,thus improving the optimizing performance.And then,use the proposed algorithm to estimate the parameter of the power load sub-model offline.The results show that the sub-model established by this method can describe the typical change pattern of load characteristics.In the establishment of online model,the specific steps,e.g.,the input interaction,conditional filter,probability updating and fusion estimation of sub-models,were all presented for the online electric load modeling.In the proposed method,the complex characteristics are simulated by some sub-models according to both offline and online information.Therefore,the nonlinear discrete change of electric load is described,resulting to the fast modeling speed and high modeling accuracy.The simulation results demonstrate its effectiveness in the end.