Abstract: With the rapid development of renewable energy sources in Liupanshui power grid, the problem of security and stability of power grid is more and more serious, and the security and stability control system is installed based on wide-area response. Taking into account such factors as load level, generation output and network structure variations, principles and characteristics of different transient instability detection methods are studied and compared, which involve the reliability, speediness and possibility of application for detection. Research results show that the perturbed voltage trajectories integral method has better rapidness and project applying feasibility, and its detecting node is studied. In addition, the two-of-n judging method is presented, based on which the instability detection strategies of stability control system for Liupanshui power grid is designed.