Leveraging Generators with Complementary Capabilities for Robust Multi-stage Power Grid Operations

In this article, we develop online multistage decisions for procuring and dispatching generators with diverse capabilities to provably ensure reliability of power grid operations under high renewable uncertainty. We jointly consider both the day-ahead reliability assessment commitment (RAC) and the real-time dispatch problems. We first focus on the real-time dispatch problem and define “maximally robust algorithms,” in the sense that they are not dominated by any other algorithm in terms of reliability. We characterize a class of maximally robust algorithms using the concept of “safe dispatch set,” which also provides conditions for verifying grid reliability for RAC. However, in general, such safe dispatch sets may be difficult to compute. We then develop efficient computational algorithms for characterizing the safe dispatch sets. Specifically, for a simpler single-bus two-generator case, we show that the safe dispatch sets can be exactly characterized by a polynomial number of convex constraints. Then, based on this two-generator characterization, we develop a new solution for the multibus multigenerator case using the idea of virtual demand splitting (VDS), which can effectively compute a suitable subset of the safe dispatch set. A distinct advantage of our proposed approach is that it intelligently exploits the complementary capabilities of generators with different ramping capabilities, and thus leads to a larger safe dispatch set than existing approaches in the literature based purely on affine policies. Our numerical results on an IEEE 30-bus system demonstrate that a VDS-based solution outperforms the standard approaches in the literature in terms of reliability, without sacrificing economy.