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Cascading Failures in Power Systems: Modeling, Characterization, and Mitigation


Liang, Chen (2022) Cascading Failures in Power Systems: Modeling, Characterization, and Mitigation. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/8817-xy25.


Reliability is a critical goal for power systems. Due to the connectivity of power grids, an initial failure may trigger a cascade of failures and eventually lead to a large-scale blackout, causing significant economic and social impacts. Cascading failure analysis thus draws wide attention from power system practitioners and researchers. A well-known observation is that cascading failures in power systems propagate non-locally because of the complex mechanism of power grids. Such non-local propagation makes it particularly challenging to model, analyze and control the failure process. In this thesis, we tackle these challenges by establishing a mathematical theory to model and characterize failure patterns, discover structural properties of failure propagation, and design novel techniques for failure mitigation.

First, we propose a failure propagation model considering both fast-timescale system frequency dynamics and the slow-timescale line tripping process. This model provides mathematical justifications to the widely used static DC model and can be generalized to capture a variety of failure propagation patterns induced by different control mechanisms of the power grid. More importantly, this model provides flexibility to design real-time control algorithms for failure mitigation and localization.

Second, we provide a complete characterization of line failures under the static DC model. Our results unveil a deep connection between the power redistribution patterns and the network block decomposition. More specifically, we show that a non-cut line failure in a block will only impact the branch power flows on the transmission lines within the block. In contrast, a cut set line failure will propagate globally depending on both the power balancing rules and the network topological structure. Further, we discuss three types of interface networks to connect the sub-grids, all achieving better failure localization performance.

Third, we study corrective control algorithms for failure mitigation. We integrate a distributed frequency control strategy with the network block decomposition to provide provable failure mitigation and localization guarantees on line failures. This strategy operates on the frequency control timescale and supplements existing corrective mechanisms, improving grid reliability and operational efficiency. We further explore the failure mitigation approach with direct post-contingency injection adjustments. Specifically, we propose an optimization-based control method with strong structural properties, which is highly desirable in large-scale power networks.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Power System; Cascading Failure; Power System Protection
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Computing and Mathematical Sciences
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Low, Steven H. (advisor)
  • Wierman, Adam C. (advisor)
Thesis Committee:
  • Yue, Yisong (chair)
  • Low, Steven H.
  • Wierman, Adam C.
  • Chandrasekaran, Venkat
Defense Date:1 June 2022
Non-Caltech Author Email:liangch93 (AT)
Record Number:CaltechTHESIS:06032022-035416994
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter 3. adapted for Chapter 4. adapted for Chapter 5. adapted for Chapters 2 and 6. adapted for Chapter 7.
Liang, Chen0000-0002-0015-7206
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14939
Deposited By: Chen Liang
Deposited On:08 Jun 2022 15:20
Last Modified:15 Jun 2022 17:32

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