Integrating High DER-Penetrated Distribution Systems into ISO Energy Market Clearing: A Feasible Region Projection Approach

Primary distribution systems are usually simplified as fixed or flexible loads in the Independent System Operator (ISO) energy market clearing with favorable computational features. However, in emerging distribution systems with an increasing penetration of distributed energy resources (DER), this simplify-cation could easily fail to capture economic features of DERs and internal limits of distribution systems, triggering line congestion and under/over-voltage issues. To this end, a feasible region projection-based approach is proposed in this paper to optimally integrate high DER-penetrated distribution systems into the ISO energy market clearing, while effectively capturing configuration details of distribution systems and fully respecting their internal physical limits such as voltage and line flow constraints. Numerical studies show efficacy of the proposed approach in achieving the optimal integration of high DER-penetrated distribution systems into the ISO energy market, while: (i) not requiring ISO directly formulating full distribution systems with exhaustive variables and constraints; and (ii) not necessitating an iterative procedure to interact ISO with distribution systems, thus compatible to the current ISO market practice.