IEEE Power & Energy Magazine - September/October 2021 - 72

earlier. Technology innovations also offer significant opportunities
to help address resilience concerns.
The findings from the analyses performed in reviewing
the events that conducted to the black system events in South
Australia in 2016 and other similar events in Australia and
worldwide suggest that when developing an overall approach
to procuring resilience solutions policy makers adopt a coordinated
portfolio approach. Such a hybrid approach with different
technologies and a mix of network and nonnetwork
solutions will enhance overall resilience while also helping
to reduce costs for consumers.
A portfolio approach reflects the characterization of resilience
described earlier, as being about using a range of resilience
solutions
✔ to make the system stronger, bigger, and/or smarter
✔ to better avoid, survive, and recover from major disturbance
events.
The " stronger-bigger-smarter " component of the framework
(Figure 3) seeks optimal tradeoff solutions among asset
redundancy, asset strengthening, and the use of more intelligent/flexible
technologies and operation policies.
On the other hand, the " avoid, survive, recover, and
learn " component of the framework looks into how different
solutions can enhance resilience at the different stages of an
extreme event.
This concept is further illustrated in Table 1, which identiFaster
Restoration,
Special Protection
Schemes,
Fast Frequency
Response, etc.
Smarter?
fies a range of resilience solutions that could improve overall
resilience. These ideas are under consideration by the NEM.
The general concept is that using a combination of solutions can
help deliver an optimal resilience outcome at the lowest total
system cost. This is based on the partial substitutability and
complementarity of the various resilience solutions described.
Partial substitutability implies that it may be possible to
Grid
Resilience
Upgraded
Infrastructure,
Stronger
Stronger?
Bigger?
Transmission
Towers, Line
Undergrounding,
Mandatory
Governor Response,
etc.
New
Interconnectors,
Operating Reserve
Redundancy, etc.
figure 3. A power system resilience enhancement framework
(adapted from Panteli and Mancarella, 2015).
use a single solution, or a combination, to achieve the same
outcome at a lower overall cost. For example, a given level of
overall resilience could be delivered in a region using a single
solution, such as constraining interconnector flows into
or out of the region (a bigger/avoid solution). However, such
an approach can come at a material cost as the limitation of
interregional flows may increase the total cost of wholesale
energy in the region.
A system operator may, therefore, look to deliver the same
level of resilience, but at a lower total cost, through a mixed
approach based on the substitutability of resilience solutions.
For example,
the operator might relax interconnector constraints
while procuring more ancillary services within the
region (a bigger/survive solution). While recognizing that these
two solutions are only partial substitutes, such an approach
could, however, deliver similar outcomes while reducing total
costs if the mixed solution costs less than the single solution.
Avoid
Stronger
table 1. Resilience solution matrix (adapted from AEMC, 2019).
Survive
Recover
* Transmission fault/damage
detection equipment
* Doubling transmission circuits
* Increase tower strength to resist
high winds
* Increased strength of tower
footing
* Firmware improvements to resist
cyberattacks
Bigger
* Conservative interconnector limits
* Enhanced special protection
schemes
* Mandate technical standards for
active and reactive power provision
Smarter
* Improved generator and system
modeling capabilities
* Enhanced demand and generation
forecasting
* Protected events/protected
operation
72
ieee power & energy magazine
* Use inertia and system
strength services to manage for
noncredible contingency
* Regional frequency control
ancillary services procurement
* Enhanced frequency load
shedding functionality
* Refinements to the operation of
special protection schemes
* Coordinated and appropriately
tuned generator control responses
* Black start services
* System restoration services
* Batteries with grid-forming
inverters to support load " islands "
and enhance restoration
* More effective system
restoration administrative and
communication processes
* Better modeling and physical
testing of black start and
restoration services
september/october 2021
* Increased multiple fault ridethrough
and active power
recovery capabilities
IEEE Power & Energy Magazine - September/October 2021

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