IEEE Electrification - December 2020 - 112

In particular, this
UAV technology is
helpful (in fact,
essential) for
monitoring highvoltage lines' rightof-way and tree
encroachment
custody.

defects in composite materials. This
type of UAV inspection is attractive
for offshore wind farms that have
poor accessibility mainly owing to
maritime weather conditions. Not
only do large PV farms require precise monitoring equipment to
detect deficiencies in the design
and the operation of PV panels, but
they also require routine cleaning of PV panels. A UAV's thermal
imaging feature can identify defective panels that can be examined
further by technical crews. In addition to utility benefits, engineering
and construction corporations
also use UAV technology for project management and quality assurance purposes.

UAVs for 3D Mapping

Performance Index

Lidar is a laser technology on UAVs that is used for
remote distance measurements, substantially speeding
up 3D mapping and modeling of structures. Using numerous overlapped photos of physical phenomena captured
by lidar-equipped, GPS-equipped, and GIS-connected
UAVs yields unprecedented 3D mapping capability. These
exciting advances in mapping science, commonly
referred to as photogrammetry, provide power companies
with 3D maps and models of power transmission and distribution lines, associated corridors, and any objects in
their path. In particular, this UAV technology is helpful (in
fact, essential) for monitoring high-voltage lines' right-ofway and tree encroachment custody. It provides the necessary time and performance data to facilitate the
construction and installation of large towers. This UAV
technology also verifies as-builts and confirms payments
for outsourced maintenance or construction jobs.

Pmin
t0 te

Survival
Avoidance

tir

Time

Recovery

Permissible Range of System Performance
Real System Performance
Ideal System Performance
Resilience Triangle

Figure 4. The three stages of resilience study modeling: avoidance,
survival, and recovery.

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I E E E E l e c t r i f i cati o n M agaz ine / DECEMBER 2020

UAVs for Post-Disaster
Management

Power companies are revisiting postdisaster management and strategies
in the face of recent hurricanes,
extensive flooding, heavy snowfalls,
record-high temperatures, recordsetting droughts, and wildfires.
These extreme events are recognized as high-impact and rare (HR)
events that can affect many power
system components simultaneously.
Accordingly, modeling and analyzing
consequences (referred to as resilience assessment) is completely different from traditional power system
reliability evaluation (which assumes
only a limited number of components on forced outage). Resilience here is defined as the infrastructure's
ability to reduce the magnitude and/or duration of disruptive HR events. The effectiveness of a resilient infrastructure or enterprise depends on its ability to
anticipate, absorb, adapt to, and/or rapidly recover from
a potentially disruptive HR event.
The resilience analysis of any infrastructure, such as
an electric power system, has three principal stages of
pre-, during-, and post-event, as depicted in Figure 4. They
are also called ex-ante, real-time, and ex-post stages. The
first stage, referred to as the avoidance stage, mainly
focuses on system robustness in a given state. This state
promotes maintaining system services using proactive
operational maneuvers before the event occurs. During
the event is known as the survival stage and responses to
the event (both system responses and operator responses) are modeled and studied. At this stage, UAV aerial
imagery is extremely helpful, particularly if the event proceeds slowly, as happened during the California wildfires
in 2019 and 2020. At the end of the second stage, system
performance inevitably degrades to some extent but
hopefully not too much. The last stage, known as the
recovery stage, begins right after the extreme event clearance and includes both damage assessment and service
restoration. Damage assessment benefits significantly
from UAV technology.
Damage assessment is inherently a time-consuming
process due to the geographical dispersion of electrical
networks. This process can take much longer in an
extreme event since there might be numerous broken
components and access roads could be blocked. UAV
aerial inspection of the suspected damage area enables
the repair crew to quickly determine the size and severity of damage as well as the estimated repair requirements and, especially, any needs for spare equipment.
With that information, repair equipment can be dispatched optimally and promptly to save lives. It is
worth noting that despite the short period of time that

IEEE Electrification - December 2020

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