Cyberphysical Challenges of Transient Stability and Security in Power Grids

Abstract:

Motivation: Power transmission networks underpin our way of life and are at the center of the transformation of the US energy system. “Keeping the lights on” as we transform an already large and complicated power system is a fundamental challenge for cyber- physical engineering. Future power networks will be instrumented with synchrophasor measurement units, communication infrastructures and distributed computing, and are therefore prototypical examples of cyber-physical systems with tightly coupled compu- tational and physical resources. Our team integrates expertise in power networks, fault detection, cyber security, control systems, distributed and multi agent systems, and net- work science.

Our focus: To develop new principles that integrate physical and cyber aspects into a unified theory, we focus on the problem of detecting and avoiding fast instabilities of power networks that can cause blackouts. We propose novel approaches to analyze these dynamic instabilities and to design cyber-physical control methods to mitigate them. The controls must perform robustly in the presence of variability and uncertainty in genera- tion, loads, communications, and the operating state, and during abnormal states caused by natural faults or malicious attacks.

First year highlights

  • Transient stability is the ability of the entire power grid to stay synchronized to- gether at 60 Hz. Almost exact conditions for transient stability have been obtained in terms of the spread of natural frequencies of generators (oscillators) and the cou- pling provided by the power grid. The next step is to use the condition to under- stand and design controls to help prevent instability

  • Electromechanical grid oscillations occur, for example, when voltages in Arizona slowly swing at about 1 Hz relative to voltages Canada. We are deriving condi- tions to suppress these harmful oscillations by redispatching generators based on measurements of the patterns of oscillations and power flows.

  • Power grid operation relies on voluminous sensor data and is robust to errors to some extent but not to cyber attacks. We designed an anomaly detector which mini- mizes the “worst-case” probability of error against all possible manipulations of up to n sensor measurements. We proved a necessary condition for the detector to be optimal and derived a heuristic detector, which is asymptotically optimal.

  • Graduate student visits: Florian Dorfler to Los Alamos national lab and Sarai Mendoza-Armenta from Physics at Universidad Michoacana, Mexico

  • We developed and taught a new cyber-physical grad course in power system syn- chrophasor measurements that integrated power engineering, systems, and net- works.

A general insight: we learned the importance of finding simple conditions sum- marizing intricate physics and engineering that can give actionable information to enable cyberphysical controls.

Award ID:  1219917

  • CPS Domains
  • Energy Sector
  • Networked Control
  • Smart Grid
  • Control
  • Energy
  • Modeling
  • Systems Engineering
  • Critical Infrastructure
  • Wireless Sensing and Actuation
  • CPS Technologies
  • Foundations
  • National CPS PI Meeting 2012
  • 2012
  • Poster
  • Academia
  • CPS PI MTG 12 Posters & Abstracts
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