A Graph-based Method for Vulnerability Analysis of Renewable Energy integrated Power Systems to Cascading Failures

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.

Automated summary

This study analyzes the vulnerability of power systems to different levels of generation uncertainty using a graph-based model and evaluation indices. The results suggest that power systems are sensitive to changes in renewable energy generation and need to operate within an allowed range of uncertainty to avoid cascading failures.