ELECTRIC POWER GRID INTERDICITION

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ELECTRIC POWER GRID INTERDICITION
Javier Salmeron and Kevin Wood, Naval
Postgraduate School Ross Baldick, University of
Texas at Austin
Sponsored by DoJ, Office of Domestic Preparedness
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Purpose

• In this presentation we will...
• Show the importance of analyzing vulnerabilities
  of electric power systems to terrorist attacks
• Present our models, and exact and heuristic
  algorithms to carry out this analysis
• Present results on standard IEEE Reliability Test
  Networks

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A Long-Recognized Issue (I)

• One can hardly imagine a target more ideal than
  the U.S. domestic energy (A.B. and L.H. Lovins,
  1983)
• Any U.S. region could suffer lasting and
  widespread blackouts if three or more substations
  were targeted. (OTA, 1990)
• The U.S. is at, or is fast approaching, a
  crisis stage with respect to reliability of
  transmission grids. (NERC, 2001)
• The U.S. electric power systems must clearly be
  made more resilient to terrorist attack.
  (Committee on Science and Technology for
  Countering Terrorism, NRC, 2002)

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A Long-Recognized Issue (II)

• (On Ahmed Ressam) They were specifically
  trained to attack critical infrastructure,
  including electric power plants. (CNN, 2002)
• And the threat isn't simply academic. U.S.
  occupation forces in Afghanistan discovered Al
  Qaeda documentation about the facility that
  controls power distribution for the eastern U.S.,
  fueling fears that an attack on the power grid
  may one day become a reality. (Energy Pulse,
  2003)
• Blue Cascades project (simulated terrorist
  attack on the Pacific Northwest's power grid).
  The study showed that such an attack, if
  successful, could wreak havoc on the nation's
  economy, shutting down power and productivity in
  a domino effect that would last weeks. (Energy
  Pulse, 2003)

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Terrorist Threat

• Potential targets
• Generating plants
• Transmission and distribution lines
• Substations
• Easy disruption Widespread damage Difficult
  recovery

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Our Approach

• Assumes Information Transparency Same
  information is available to both sides
• Uses optimization to assess worst-case
  disruptions
• Goal
• To provide insight on physical vulnerabilities
  and protective plans that proactively hedge
  against disruption caused by terrorist attacks

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Mathematical Analysis of the Problem

• In order to better defend the electric grid it is
  valuable to understand how to attack it!
• Optimal power flow model (minimizing load
  shedding)
• Interdiction model (maximize disruption)
• Additional features of the problem are
• Time scale Very short-, short-, medium- and
  long-term
• Customer types ability to share the pain
• Uncertainty about terrorist resources
• Assumptions on protection resources

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Power Flow Model (DC Approx.)
s.t.
i bus, l line, g generator, c customer
sector PLine, PGen power (MW) S power shed
? bus phase
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Interdiction Model
Where
s.t.
Etc...
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Heuristic
Solve the DC-OPF Power Flow Model given the
current grid configuration
Based on the current and previous flow patterns,
assign a Value (V) to each interdictable asset
Interdict the assets that maximize Total Value
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Exact Linearization of the Model

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IEEE Reliability Test System 96-99
Total load 2,850 MW
Interdiction resource 6 terrorists Line
x1 Single transformer x2 Bus or substation x3
Salmeron, Wood and Baldick (2004), IEEE
Transactions on Power Systems
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IEEE Reliability Test System 96-99
Load 5,700 MW
12 terrorists
Shedding 2,516 MW
Salmeron, Wood and Baldick (2004), IEEE
Transactions on Power Systems
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System Restoration
MW shedding
t
gt1 months
(Attack)
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IEEE Reliability Test System 96-99
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Results for the Linearized MIP