IEEE Power & Energy Magazine - January/February 2022 - 74

Quickly and accurately locating faults is key
for long transmission lines traversing difficult-to-patrol
terrain, and this becomes critical during fire season.
✔ advanced distribution system planning
✔ DER integration and operation
✔ distribution load, DER production, and electric vehicle
demand forecasting
✔ monitoring and control of electric transportation infrastructure
✔
power apparatus monitoring and diagnosis
✔ asset management of critical infrastructure
✔ advanced microgrid applications and operation.
PMU data streams that are already being collected from the
first FCP installations assist with the development of these
use cases.
Other Initiatives for Fast Fault Clearing
and Fire Risk Reduction
Transmission Line Fault Protection
and Teleprotection
Quickly and accurately locating faults is key for long transmission
lines traversing difficult-to-patrol terrain, and this
becomes critical during fire season. Traditional methods of
fault location based on impedance calculations introduce multiple
sources of error when determining locations. SDG&E is
deploying the latest generation of relays with traveling wave
fault location on 500-, 230-, and 69-kV transmission lines.
With traveling wave fault location, a simple calculation is
based on a ratio of the times it takes for high-frequency traveling
waves to propagate from a fault to the terminals of a line.
Using this method, the location can potentially be determined
within one tower span and reported to operations from the
relay the instant the fault occurs.
SDG&E is also using an overlayed geographic information
system (GIS) map to help field crews pinpoint a location
reported by a relay. An additional benefit is traveling
wave line monitoring-the ability to detect temporary disturbances
from equipment, such as specific insulators that
could cause permanent faults in the future. This functionality
is being configured to notify field crews to inspect line
sections where traveling waves indicate a potential precursor
to failure. This technology could further reduce the risk of
fire ignition from a transmission line.
PMU-Based, Wide-Area Situational
Awareness and Transmission
Visualization System
SDG&E is among the utilities deploying wide-area situational
awareness (WASA) systems in which PMUs distributed
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ieee power & energy magazine
across the grid stream data to system operators at control
centers to monitor network behavior. WASA deployment
has evolved from a grid observation system built on PMU
deployment during the past decade, now extending to most
transmission lines and other system elements. It presently
covers all 230- and 500-kV buses and transmission lines
and is spreading to the 138- and 69-kV systems. The PMUs
stream data at 30 or 60 frames/s providing exact time and
angle relationships of measurements from across the grid.
This is vastly superior to today's SCADA and energy management
system (EMS) databases that depend on legacy
SCADA remote terminal units transmitting unsynchronized
values every 4-5 s. PMUs gather phase and sequence values
of voltages and currents, power flows, frequency, and rate of
change of frequency. Binary and analog point values are also
being included in the PMU data streams to provide breaker
statuses, fault distances, and fault type indications.
Today's system serves as a tool for engineers and operators
to observe system behavior and perform postmortem
analysis of disturbances and events. It has been installed in
the transmission system operator console as a nonoperational
tool for the past decade. This enables operators to become
familiar with the technology, understand system events and
data in real time, and review events and information that are
not observable via the EMS. Streamed grid measurements
and system status displays are available, as Figure 9 shows.
A new WASA architecture with advanced cybersecurity and
regulatory security compliance is being deployed for realtime
operations to complement the EMS. This will enable
transmission system operators to make real-time operating
decisions based on information from the WASA system
and EMS.
Several wildfire management applications are being
developed for the WASA system, including a multilayered
GIS map-based visualization software system that will
show accurate fault locations plus point-on-wave event and
weather (wind, fire, and lightning) data, helping the company
quickly dispatch personnel, conduct event analyses and
restoration, and manage PSPS events.
Transmission FCP Systems
We have explained how SDG&E pioneered the development
of a distribution FCP system to collect streaming
synchrophasor measurements from distribution circuits
and rapidly trip a circuit section with a broken conductor
so that the device lands dead. FCP is now the subject
of a widespread installation program. In 2019-2020,
january/february 2022
IEEE Power & Energy Magazine - January/February 2022

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