Transient instability risk assessment based on trajectory sensitivity

The traditional transient instability analysis method based on time-domain simulation without considering future uncertainties has some limits in practice, so a transient risk assessment method based on trajectory sensitivity is proposed in this paper. The contingency cost is considered as minimum control cost to move the system from instability to stability, and the sensitivities of relative rotor angle with respect to output of generators and dispatchable load are employed to properly consider the transient stability constraints in the optimal power flow (OPF). The minimum objective of OPF is the determination of contingency cost. With the load curtailment and control cost produced by OPF, some instability risk indices are obtained. The correctness and effectiveness of the presented method is finally validated by New England 39-bus system.