Enhanced risk-based SCOPF formulation balancing operation cost and expected voluntary load shedding

In the framework of approaches which question the narrow scope of the deterministic N-1 security criterion, this work proposes an enhanced risk-based AC security-constrained optimal power flow (RB-SCOPF) problem formulation to aid transmission system operators (TSOs) trading-off economy and (thermal) security. The system security is controlled through an overall system risk constraint, which accumulates the individual risk related to each contingency, defined as the product between the probability of contingency occurrence and the contingency severity. The latter is expressed in terms of the amount of voluntary load shedding which, complementary to conventional corrective actions, is able to correct violation of post-contingency long-term thermal limits. The existing RB-SCOPF formulations are enhanced with short-term thermal post-contingency limits, aimed at avoiding cascade line tripping, and TSO operating rule. The main features of the RB-SCOPF formulation are illustrated in the IEEE 118-bus system.