Coupling optimization and dynamic simulation for preventive-corrective control of voltage instability

Abstract—This paper proposes an approach coupling secu-rity-constrained optimal power flow with time-domain simulation to determine an optimal combination of preventive and corrective controls ensuring a voltage stable transition of the system towards a feasible long-term equilibrium, if any of a set of postulated contingencies occurs. A security-constrained optimal power flow is used to adjust the respective contribution of preventive and cor-rective actions. Furthermore, information is extracted from (quasi steady-state) time-domain simulations to iteratively adjust the set of coupling constraints used by a corrective security-constrained optimal power flow until its solution is found dynamically secure and viable. Numerical results are provided on a realistic 55-bus test system. Index Terms—Emergency control, optimal power flow, preven-tive control, time-domain simulation, voltage stability. I