Flexible and economic dispatching of AC/DC distribution networks considering uncertainty of wind power

Abstract

In order to cope with the uncertainty power and consumption problems in AC/DC distribution networks after accessing high-permeability renewable energy source (RES), a flexible economic dispatching method for the AC/DC distribution networks considering the uncertainty of wind power is proposed based on the flexibility operation theory. First, considering the flexibility of regulation range, speed, and time, the source-network-load flexibility resources of AC/DC distribution networks are quantitatively evaluated. An evaluation index and a calculation method of the operation flexibility for the AC/DC distribution networks are defined. Then, based on the nonparametric kernel density estimation and confidence interval method, the constraints transformation of flexibility requirement in distribution networks considering the uncertainty of wind power is implemented. Finally, a multi-objective day-ahead flexible and economic dispatching model of the AC/DC distribution networks is established, which takes the operation economy and voltage quality of distribution networks as the objective function and the controllable operation parameters of voltage-source converters (VSCs) and AC/DC networks as the decision variables. The modified IEEE-33 system with flexible multi-terminal interconnection is simulated and analyzed. The result shows that the proposed method further improves the node voltage level and the RES consumption level and reduces the network losses and the total dispatching cost while ensuring the AC/DC distribution network to cope with the fluctuation of the system uncertainty.