Cascading Failure Mitigation via Transmission Switching

TL;DR

This paper introduces a new approach using system stress metrics to evaluate and mitigate cascading failures in power systems through transmission switching, demonstrating its effectiveness in reducing system vulnerability.

Contribution

It develops an algorithm based on line-outage distribution factors to identify transmission switching options that lower system stress and risk of cascading failures.

Findings

Transmission switching can reduce system stress and failure risk.

The proposed algorithm efficiently identifies switching candidates.

Results on IEEE 118-bus system validate the approach.

Abstract

After decades of research, cascading blackouts remain one of the unresolved challenges in the bulk power system operations. A new perspective for measuring the susceptibility of the system to cascading failures is clearly needed. The newly developed concept of system stress metrics may be able to provide new insights into this problem. The method measures stress as susceptibility to cascading failures by analyzing the network structure and electrical properties. This paper investigates the effectiveness of transmission switching in reducing the risk of cascading failures, measured in system stress metrics. Based on line-outage distribution factors, an algorithm is developed to identify and test the switching candidates quickly. A case study analyzing different stress metrics on the IEEE 118-bus test system is presented. The results show that transmission switching identified by our proposed algorithm could be used in preventive as well as corrective mechanisms to reduce the system's susceptibility to cascading failures. Contrary to the conventional operation wisdom that switching lines out of service jeopardizes reliability, our results suggest the opposite; system operators can often use transmission switching, when the system is under stress, as a tool to reduce the risk of cascading failures.