Optimizing admissible region of nodal net load for active distribution network based on cost/benefit analysis

As the proportion of renewable energy sources (RESs) increases, active distribution network (ADN) operation becomes a more challenging problem due to unpredictable nature of RESs. To address this problem, a new dynamic economic dispatch (DED) for ADN is proposed which can determine the optimal scheduling results based on cost/benefit analysis. Intervals with variable endpoints are applied to describe the nodal net load, which is also named as admissible region in this paper. The admissible region of nodal net load and other scheduling results are simultaneously determined by striking a balance between operation cost when net load varies within the corresponding intervals and benefit represented by reduction of operation risk when net load varies out of their intervals. To facilitate the solution, a new injection shift factor (ISF) of the linearized DistFlow branch equations is proposed, and the voltage magnitude and reactive power can be well addressed, which especially fits for ADN. A surrogate affine policy is applied to avoid the introduction of bilinear terms. And a new step-superimposing linearization method for risk cost is proposed by exploring the specific characteristics of risk cost expression, then binary variables can be eliminated in the model. Finally, this model is recast as a linear programming problem and the computation efficiency can be guaranteed. The validity and effectiveness of the proposed model are illustrated on the IEEE 33-node and 69-node distribution systems.