Multi-time Scale Optimal Dispatch Of AC/DC Active Distribution Network

The development of AC distribution technology which has a significant impact on the AC/DC hybrid topology of distribution,which made it possible for DG and ESS to connect efficiently.Compared with AC distribution,AC/DC distribution is an important development direction in the future,which can not only can effectively reduce line loss,but also ensure the quality of power and transmission distance.It is possible to improve the reliability and economy of AC/DC distribution,ensure the quality of electric power system of power supply and distribution network,saving the operation and maintenance costs by researching AC/DC distribution optimal dispatch,which are the indispensable part of the study of AC/DC distribution network.A multi-time scale optimal operation model based on scenario method and model predictive control(MPC)in AC/DC distribution network is established.A Markov-chain dynamic scenario method is proposed,which generating scenarios by characterizing the forecast error via empirical distribution.Considering the time correlation of forecast error,Markov-chain is adopted in the Markov-chain dynamic method to simulate the uncertainty and variability of wind and load with time.A multi-time scale optimal operation strategy based on MPC is proposed.The operation scheduling of operation units is solved in day-ahead and intraday optimal operation by minimizing the expected value of total cost in each scenario.In the real-time optimal operation,the stability and robustness of system operation is considered.MPC is adopted in the real-time optimal operation taking the intraday scheduling as reference and using roll optimization method to compute real-time optimal operation scheduling to smooth the output power.A solution method based on Benders decomposition and the primal-dual interior point method is proposed.The Benders decomposition is uesd to decompose the day-ahead model into main problem containing only integer variables and subproblem containing only continues variables,and then and the feasible cut and the optimal cut were generated to solve the model.The intraday and real-time optimal scheduling models are solved by primal-dual interior point method,the optimal solution of intraday and real-time optimal scheduling models is obtained by changing the search direction and iteration step of variables by solving the modified equation.Finally,The simulation results in a 50-node system with uncontrollable distributed energy demonstrate that the proposed optimal dispatch model.