Applying the Distribution System in
Grid Restoration/NERC CIP-014 Risk
Assessment
Srijib Mukherjee, Ph.D., P.E.
UC Synergetic
Classic Power System Restoration
Distributed Generation in System
Restoration
• Ramp-in a Distributed Generation resource
– Is the DG resource capable of generation-load balance?
– Is it tied to a storage device with sufficient ramp and
regulation capability?
• Find an initial low to medium voltage path to energize
• Energize line and pick up load
• Synchronize to bulk power grid
– Outline energized switching sequence path
– How do I avoid false tripping of feeder breakers?
• Consider short circuit contributions for DG resources
– Do I build upward, build downward, other variations?
The Big Picture
Reverse Flow and Grid Support
Distribution System Grid Restoration
• What’s the status of the radial system
– How can we maximize our DER resources that
meet the “black start criteria requirement”?
– What is the capability of power transfer in our
distribution network?
– Are there any operating constraints?
– How do we pick up load and maintain
frequency balance?
Frequency balance - California’s Duck Curve
What is NERC CIP-014
• A Critical Infrastructure Protection standard
to identify and protect Transmission
stations and substations, and their
associated primary control centers, that if
rendered inoperable or damaged as a result
of a physical attack could result in
widespread instability, uncontrolled
separation, or Cascading within an
Interconnection.
Applicability
• Today’s standard requires:
– Any Transmission Owner that owns:
• Transmission Facilities 500 kV or higher.
• Collector bus for a generation plant is not
considered a transmission facility. Instead it is a
part of the generation interconnection facility
• Transmission Facilities operating between 200 kV
and 499 kV at a single station or substation, where
the station or substation is connected at 200 kV or
higher to three or more other Transmission
stations or substations
How may it change if we used the Distribution System
for System Restoration?
• Functional entities would now be considered:
– Distribution Owners
– Generator Owners of Renewable Resources
• DER resources that are critical in the grid restoration
process would need to go through a risk assessment
evaluation
– Contribution to frequency stability
– Contribution to voltage stability
– Applicable threat conditions on that asset
– A vulnerability assessment of that asset
Risk w.r.t. CIP-014. Consider ..
• Event Driven Risk Indicators
– Prioritize applicable events based on distribution
system integrity, equipment performance, and/or
engineering judgment
– Consider applying a ranking methodology in
association with TO’s input and CIP-014 requirements
• Condition Driven Indicators
– Assess on a set of measurable conditions for
reliability. Examples: abnormal topology, alternative
generation dispatches, power transfer between
systems, etc.
Threat defense mechanisms
• Transmission systems are planned and operated to
withstand N-1 contingency conditions
– Should Distribution resources be studied in the same
fashion?
• Think of proposing a system that has the ability to defend
against attacks of multiple components including bulk
power transformers.
• Example: Attack detection tools that monitor traffic
patterns simultaneously correlates events at multiple
substations can help in early detection of coordinated
attack scenarios.
Conclusion
• Consideration of Distribution System assets in
system restoration efforts
• Advantages to doing this :
– Diversification of risk to critical assets
• Multiple black start points
– Greatly reduces vulnerability of the system to
terror threats
– More robust alternatives to restoring load
effectively
Questions?
• Contact Information:
– Srijib Mukherjee
– Email: smukherjee@ucseng.com
– Cell: (919)302-4956