A Graph-based Method for Vulnerability Analysis of Renewable Energy integrated Power Systems to Cascading Failures. (March 2021) - Yang, Shenhao
Highlights: The N-2 contingency induced cascading failures are analyzed, an interaction graph-based method is proposed, which can be used to investigate the N-2 contingency-related vulnerability and the interaction of vulnerable lines in power systems. In power systems, only a little fraction of lines play the role in propagating cascades when the systems suffer N-2 contingencies, where part of lines occupy the propagation center. The vulnerability distributions of power systems present different levels from heterogeneous to homogeneous. The vulnerability of most lines is sensitive to the power system's operation state. In some cases, some lines' vulnerability has a larger variation range. Power systems would be more vulnerable to cascading failures when facing a larger uncertainty level which exceeds a certain range. To mitigate the impact of uncertainty on system vulnerability, the proposed indices can be used to evaluate this range. Abstract: A large amount of uncertainty introduced into power systems may affect the system vulnerability to cascading failures. The objectives of this study are to analyze the power system vulnerability to cascades considering higher security criteria and to analyze the variation of the power system vulnerability considering renewable energy integration. To this end, we use a graph-based model to reflect cascades propagation, which is constructed by a thermal inertia-based cascades model incorporating an N-k contingency sampling algorithm. Based on the graph model, comprehensive evaluation indices are proposed to analyze the power system vulnerability in terms of its variable operation state and different generation uncertainty levels. Results show that the graph-based method can reveal cascades propagation, and provides an effective way to visualize and analyze the system vulnerability. Results also show that power systems' vulnerability is sensitive to the variation of renewable generation, the system would be highly vulnerable to cascades when facing a large uncertainty level that exceeds a certain range. This implies that it is important to limit power systems to operate within the allowed uncertainty range. The proposed approach can help operators to test the system resilience and to analyze the scenario-based risk of systems.