Incorporation of N-1 Security into Optimal Power Flow for FACTS Control

As the electric power consumption increases continuously, the stress on the power grid grows and therefore, failures of system components become more probable. When the system is not in an N-1 secure state, an outage of a single component may trigger cascading failures in the worst case resulting in a blackout. In this paper, a new current injection method is developed such that the apparent power flows on lines in case of a line failure are very accurately determined by a linear equation system. Based on this, a method using FACTS devices to keep the system in an N-1 secure state is presented. The set values of the FACTS devices are determined by an optimal power flow (OPF) control where the current injection method is used to include N-1 considerations focused on line failures. Thus, a control strategy is outlined which reduces the risk of cascading failures