Aggregate Temporally Coupled Power Flexibility of DERs Considering Distribution System Security Constraints

The proliferation of distributed energy resources (DERs) makes it possible for the transmission system operator to exploit the DERs' power flexibility. Modeling the aggregate power flexibility of different types of DERs in the distribution system continues to be a vexing scientific problem. This paper rigorously derives the exact mathematical expression of aggregate temporally coupled power flexibility of DERs considering linear distribution system security constraints. A flexibility optimization method and a backtracking elimination method are proposed to calculate the parameters in the aggregate flexibility model. Based on the exact model, an approximate model is proposed to reduce the complexity, which can be used for practical applications. We further developed a transmission system economic dispatch model considering the power flexibility of distribution systems. Finally, numerical tests are carried out on IEEE test systems to verify the correctness of the derived model and the effectiveness of the proposed methods.