Distributionally robust chance-constrained unit commitment considering the real-time reserve deployment of pumped-storage hydro units in the Korean power system

Abstract

Due to the expansion of renewable energy resources, the need for securing reserves exceedingly heightens. Most of all, pumped storage hydro (PSH) units play an important part, due to their quick response speed and steep ramp rates. However, the PSH units have limited resources, making it hard to schedule reserve. Especially, in the case of Korea where the ancillary service market is not activated, the ISO has responsible for scheduling and operating the reserve of the PSH units. To handle this problem, this paper proposes a day-ahead unit commitment (DAUC) considering the actual operation of PSH units in real-time by utilizing distributionally robust chance-constraints (DRCC) under the uncertainty of demand variation. The DAUC model is formulated as a mixed integer linear programming (MILP) composed of thermal, nuclear, and PSH units complying Korean reserve standard. Real-time dispatch problems are formulated to verify the proposed model and Korean power system data are employed for case studies. The results demonstrate that the proposed method can operate the system stable in real-time while satisfying the constraints of the PSH units.