|Yihan Zou||Purdue University, USA|
|Xiaojun Lin||Purdue University, USA|
|Dionysios Aliprantis||Purdue University, USA|
|Minghua Chen||The Chinese University of Hong Kong, P.R. China|
The uncertainty and variability of renewable generation pose significant challenges to reliable power-grid operations. This paper designs robust online strategies for jointly operating energy storage units and fossil-fuel generators to achieve provably reliable grid operations at all times under high renewable uncertainty , without the need of renewable curtailment. In particular, we jointly consider two power system operations, namely day-ahead reliability assessment commitment (RAC) and real-time dispatch. We first extend the concept of "safe-dispatch sets" to our setting. While finding such safe-dispatch sets and checking their non-emptiness provide crucial answers to both RAC and real-time dispatch, their computation incurs high complexity in general. To develop computationally-efficient solutions, we first study a single-bus case with one generator-storage pair, where we derive necessary conditions and sufficient conditions for the safe-dispatch sets. Our results reveal fundamental trade-offs between storage capacity and generator ramp-up/-down limits to ensure grid reliability. Then, for the more general multi-bus scenario, we split the net-demand among virtual generator-storage pairs (VGSPs) and apply our single-bus decision strategy to each VGSP. Simulation results on an IEEE 30-bus system show that, compared with state-of-art solutions, our scheme requires significantly less storage to ensure reliable grid operation without any renewable curtailment.