Research On Stochastic Dynamic Simulation Method Of Active Distribution Networks Based On SUNDIALS

The increasing penetration of distributed generators(DGs)and demand for electricity have brought new challenges to the secure and stable operation of distribution networks due to the randomness of DGs and loads.Dynamic simulation as a key technology to effectively analyze the operation characteristics of active distribution networks(ADNs)has become an important research field.Therefore,this paper focuses on the dynamic simulation of ADNs with stochastic characteristics of DGs and loads.The major contributions can be summarized as follows:(1)A deterministic dynamic simulation method for ADNs based on SUite of Nonlinear and DIfferential/ ALgebraic equation Solvers(SUNDIALS)is realized.Firstly,this method can solve the general form of the deterministic dynamic simulation model for ADNs by SUNDIALS,and the multi-time-scale characteristics of the system can be accurately simulated.Secondly,the simulation analysis is carried out to verify the applicability of the proposed method by comparing the simulation results with DIgSILENT/ PowerFactory.Meanwhile,the deterministic dynamic simulation method lays the foundation for the SUNDIALS based stochastic dynamic simulation method.(2)This paper proposes a stochastic dynamic simulation method for ADNs based on SUNDIALS.Firstly,an improved method is proposed to solve the general form of stochastic dynamic simulation model for distribution networks.Secondly,the numerical analysis shows that the method has 0.5-order strong convergence,1-order weak convergence and 0.5-order mean square convergence.Finally,a numerical example is given to test the proposed method.The accuracy and efficiency of the proposed method are verified by taking into account the stochastic characteristics of the ADNs.(3)A stochastic dynamic parallel multi-step simulation method for ADNs based on SUNDIALS is proposed.Firstly,to enhance the simulation accuracy of the improved method for solving stochastic differential algebraic equations(SDAE),the improved SDAE multi-step method is realized,and the mean square convergence of the method is analyzed.Secondly,according to the independent characteristics of Monte Carlo simulation processes,the stochastic dynamic parallel simulation of ADNs based on SUNDIALS is realized.This method can improve the accuracy of stochastic dynamic simulation,also greatly improve the simulation efficiency.Finally,by comparing with the results of stochastic dynamic simulation and deterministic dynamic simulation through the simulation analysis and verification,the former can veritably reflect the stochastic operation characteristics of the system,and get more reasonable operation strategies or plans in practical engineering applications.