A Two-Layered Framework for Robust Dispatch with Transmission Constraints

This paper presents a two-layered framework for managing multi-interval economic dispatch with both transmission and ramping constraints in electric energy systems with a large penetration of variable resources. The proposed model is aimed at ensuring that there is sufficient flexibility in the dispatch to manage large net load ramp events while observing the transmission constraints in the power network. A flexibility metric termed lack of ramp probability (LORP) is used to quantify the ramp capability. This metric is shown to be applicable in system-wide and decomposed zonal settings. A two-layered robust optimization-based dispatch is then formulated as an approach to ensuring a level of LORP flexibility with transmission constraints in large power networks. This two-layered approach is shown to be rigorous in terms of guaranteeing flexibility and is implementable for real-time dispatch in multi-zonal energy systems. The performance of the proposed dispatch framework is illustrated in a modified IEEE 24-bus Reliability Test System.