Quantitative Weak Link Identification Method Based on Impedance Angle

Although energy reform and advances in power electronics technology have led to the transformation and upgrading of the power system, the significant increase in the share of renewable energy and power electronics in the grid has posed new challenges to the power system stability. In the traditional power system, the combination of voltage-power-angle-frequency stability and wide-band oscillation stability has the dominant factor of instability. In this case, the weak link of the power system is difficult to be identified effectively. This paper summarizes and analyzes the characteristics of the typical wideband oscillations. Then, based on impedance angle, this paper proposes a quantitative weak link identification technique to realize the analysis of power system instability factors. It uses the equivalent model of power system to establish the impedance angle model. Furthermore, it establishes a kind of mapping to reflect the relationship between the impedance angle and the unstable dominant factor, based on which it establishes the stability margin, so as to judge the unstable dominant factor and quantitatively identify the weak link of the power system. Finally, by simulating and verifying the identification of the quantitative weak link and the impedance angle simulation system, this paper proves that the system has good effect.