A fast setting method of generator tripping strategies in transient stability control based on the concavity and convexity of phase trajectory is proposed. This method can improve the efficiency of strategy table setting without numerous repeated simulations. During anticipated serious faults with significant impact on the system

the stability of the system's transient power angle can be detected based on the time-domain simulation. When the system is transiently unstable

an accurate control strategy can be calculated by the information on the simulation result including power angles and rotor speeds at the control moment and the unstable equilibrium point(UEP). The simulation result of an actual system shows the rapidity of the method.