Towards Stochastic (N-1)-Secure Redispatch

Abstract

The intermittent nature of renewable power availability is one of the major sources of uncertainty in power systems. While markets can guarantee that the demand is covered by the available generation, transmission system operators have to often intervene via economic redispatch to ensure that the physical constraints of the network are satisfied. To account for uncertainty, the underlying optimal power flow (OPF) routines have to be modified. Recently, polynomial chaos expansion (PCE) has been suggested in the literature as a tool for stochastic OPF problems. However, the usage of PCE-based methods in security-constrained OPF for (N-1)-secure operations has not yet been explored. In this paper, we propose a procedure that iteratively solves a PCE-overloaded stochastic OPF problem by including line outage constraints until an (N-1)-secure solution is achieved. We demonstrate the efficacy of our method by comparing it with a Monte-Carlo simulation on a 118-bus example system.