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Question:
Why is phasor technology important?
Answer:
Operation of the power system is based on SCADA and EMS systems
that have evolved over the last 50 years. Phasors is the
next generation of measurement technology that is needed
for the real-time wide area monitoring of the power
system.
Phasors address
the problems that have surfaced in most of the major
blackouts that have occurred around the world, notably
August 2003 Eastern Interconnection Blackout in the
U.S., August 1996 Western Interconnection Blackout in the
U.S., Summer 2003 and 2004 blackouts in Europe and
elsewhere.
All these blackout investigations reached some
combination of the following conclusions:
-
Lack of
wide area visibility
-
Lack of
time-synchronized data
-
Inability
to monitor system dynamics behavior in real-time.
Phasor technology addresses these shortcomings
Question:
What insights will phasors provide for operation and
management of the power system?
Answer:
Phasors can be considered as the MRI of the power
system providing high resolution, time-synchronized
data for system-wide grid dynamics visibility, compared
to the “x-ray quality” visibility of the traditional
SCADA-based systems.
Question:
Can SCADA provide the same insights on power system
dynamics and wide-area visibility as phasors?
Answer:
No. SCADA was designed for local control area monitoring
and management. Power system interconnections and
development of regional markets have shifted the focus
for grid monitoring and control to much larger
geographic footprints and adapting SCADA to meet this
emerging need is cost prohibitive. Phasors overcome the
limitations of SCADA for wide area, time-synchronized,
dynamic, real-time grid monitoring and control.
Question:
How does phasor technology compare with SCADA?
Answer:
The table below compares phasor capabilities with SCADA:
|
ATTRIBUTE |
SCADA |
PHASOR |
|
Measurement |
Analog |
Digital |
|
Resolution |
2-4 samples per sec |
Up to 60 samples per sec |
|
Observability |
Steady State |
Dynamic/Transient |
|
Monitoring |
Local |
Wide-Area |
|
Phase Angle Measurement |
No |
Yes |
|
Measured Quantity |
Magnitude – (RMS) – MW,
MVAR |
Magnitude (RMS) and phase
offset from common reference – MW, MVAR, and
Angle Difference |
Question:
What technologies are critical for cost effective
utilization of phasors?
Answer:
Application of phasors requires integrated use of
several key technologies for collection of data, transmission of
data, and management of data. Recent advances in computers, network
management and sensing technologies make the application of phasors
technically and economically feasible
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