Research On Power Load Modeling Based On Adaptive Interacting Multiple Model Algorithm

Power load is one of the four major components of the power system,so the accurate load model plays an important part in the simulation and stability evaluation of power system.In view of the distribution,time-varying and complexity of power load,accurate load modeling has been an important problem to be solved.Moreover,with the continuous extension of power grids and increasingly abundant of load categories,there are inevitable problems of load modeling,such as the single model structure and low timeliness of modeling.In this paper,load model selection,model interaction and information fusion are studied intensively in the frame of the Adaptive Interactive Multiple Load Modeling algorithm,thus establishing a new load modeling system.Concretely,it includes several aspects as follows.(1)To overcome the model competition caused by complex load model set,the model selection should be analyzed to choose the best-matched models from model set to participate in model interaction.Load model set need to be initialized based on the model set determination;Each model carries out state estimation according to the load characteristic to calculate the model errors;Calculate the Normalized Innovation Square Sum and build the model selection mechanism,thus determining the best model set.(2)Based on the best load model set generated by model selection,model interaction in the best load model set should be in-depth studied.Through the Markov transition relationship between each status,the mixed state estimated value and covariance of each model at each moment can be calculated according to the mixed probabilities,thus generating the interactive result of load model set.(3)Information fusion should be studied to generate the load model that matches with the actual power system.Firstly,each best model carries out state estimation based on the interaction result,in order to estimate the state variables and covariance of the next moment.Secondly,every weights of load model are updated according to the matching degree between each model and the actual system.Finally,the state estimation results of each model are merged and exported according to their weights.PSCAD is adopted to conduct the load model construction and fault simulation.MATLAB is adopted to simulate the Adaptive Interactive Multiple Load Modeling algorithm.The effectiveness of model selection,model interaction and information is validated by numerical simulations.The result shows that the proposed load modeling algorithm can solve the time-varying problem of load model,and it has important theoretical value and practical significance for the study of accurate power system modeling.