Wide Area Measurement
System Integration
GE Consumer & Industrial
Multilin
The Need for Wide-Area Measurements
• Following the blackout, a federal commission
was appointed
• Fault found with utility companies: no real-time
knowledge of the state of the power system was
available
• Recommendation made: establish a real-time
measurement system and develop computer based
operational and management tools
This
This Was
Was after
after the
the 1965
1965 blackout!
blackout!
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GE Consumer & Industrial
Multilin
June 3006
Wide Area Measurement and Control
State
Measurement
Input Data:
EMS applications
for self-healing grid
Data Synchronization &
Control Coordination
•1-60 Phasors/sec
•Control Range
•Control Device Status
Kemano
Phasor
Measurement
Units
C O
Wide Area Control
•Operate Point change
•Linear Control
•On/Off
Peace River
L O
McNary
John Day
Table Mtn.
Colstrip
Midpoint
SCE
LADWP
SDG&E
Diablo Canyon
Jim Bridger
500kV Lines
345kV Lines
230kV Lines
DC Lines
IPP
PG&E
Moss Landing
T
R
Transmission Paths
Grand Coulee
Malin
N
Hoover
Mohave
Navajo
San Juan
Four
Corners
Cholla
Palo Verde
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GE Consumer & Industrial
Multilin
June 3006
Wide Area Network Structure
Link to Enterprise LAN / WAN
Office PC using
Internet Explorer
Super
PDC
Issues:
• Performance
• Reliability
• Data Security
Utility Wide Area Network WAN (Intranet / Internet)
PDC
δ1
δ2
δ4
Control Area 1
δ3
PDC
PDC
δ1
δ2
δ4
Control Area 2
δ3
δ1
δ2
δ3
δ4
Control Area 3
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GE Consumer & Industrial
Multilin
June 3006
Reporting Hierarchy
PDC – Phasor Data Concentrator
Human Monitoring / EMS > 1 sec
1 Phasor/Sec
National Operation
Regional
High-speed
Operation
Decisions
100 ms – 1S time frame
1-15 Phasors/sec
PDC
PMU
PMU
Very High-speed
Decisions
10-100 ms time frame
20-60 Phasors/
Sec
. . . PMU
PMU
PDC
PMU
PDC
. . . PMU
PMU
PMU
. . . PMU
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GE Consumer & Industrial
Multilin
June 3006
Communication Network Requirements
• Guaranteed bandwidth – for Streaming Data
• Adjustable bandwidth – for File Transfer
• Settable priority – for Control
• High-availability (99.99%)
• Low latency
• Standards based
• Scalable
• High noise immunity
• Support for other functions
• Automatic Configuration
• Network monitoring/management
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GE Consumer & Industrial
Multilin
June 3006
Synchrophasor System –
Communication Option
User
Data
Configuration/File-
Interface/Apps
Archive
Archive/SOE
• Streaming Synchrophasors
• Status
• Settings
• Triggered files
• SOE
SDH
Mux
PMU
Station 1
Station 2
Station n
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GE Consumer & Industrial
Multilin
June 3006
Phasor Data Concentrator Function
Decimated Phasor Stream
1-15 Phasors/sec.
Applications
OPC/SQL – High Speed
OPC/SQL – Archive
DB
Data Translation/Presentation
Data Collection
Per C37.118 over RS485, C37.94, or Ethernet
Data Rate:
20-60 Phasors/sec
PMU
Communication options:
Multiplexer, Modem, etc.
PMU
.....
PMU
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GE Consumer & Industrial
Multilin
June 3006
Client/Server Functionality
• Client:
PDC
– Request for Configuration
– Request to Start/Stop Stream
– File Request (not addressed in Standard)
– Command Issuance
Req
Resp
• Server:
– Streams data / Sends configuration / files when
requested
– Provides operational status
PMU
• Clock Synched
• Triggered
• Configuration Changed
• Responds to Commands
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GE Consumer & Industrial
Multilin
June 3006
Data / Format Choices
• Data:
– Sequence Voltages/Currents
– Analog Values
– Status
•16 Bit Integer vs. 32 Bit Real
• Polar vs. Rectangular format
PMU Data Stream:
Up to 100 Times faster than Existing SCADA
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GE Consumer & Industrial
Multilin
June 3006
C37.118 Self Description
On Request from the Client, a PMU shall return:
• PMU ID & Station Name
• Time
• Data Format
• Number of Phasor, Analog, & Digital Channels
• Channel Names
• Channel Scale factors
• # of PMUs included in the stream
• Nominal Frequency
• Stream Rate
• Configuration change count
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GE Consumer & Industrial
Multilin
June 3006
Communication: TCP vs. UDP
TCP Guarantees Reception – but Bogs Down Communication
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GE Consumer & Industrial
Multilin
June 3006
Streaming Data Rates - 1
• Packet Model #1:
– 16 Phasors
– 16 Analogs
– Frequency
– ROCOF
– 2 Digital Words
> All Real Numbers
> 60 Packets/sec
• Communication Bandwidth Requirement:
– 106,560 Bits/sec
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GE Consumer & Industrial
Multilin
June 3006
Streaming Data Rates - 2
• Packet Model #1:
– 16 Phasors
– 16 Analogs
– Frequency
– ROCOF
– 2 Digital Words
> All 16 bit Integers
> 60 Packets/sec
• Communication Bandwidth Requirement:
– 58,560 Bits/sec
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GE Consumer & Industrial
Multilin
June 3006
Total System Data Streams
• Given 100 PMUs
> 60 packets/sec with Real Numbers results in:
– Aggregate data stream: 10,656,000 bps
– 6,000 Records/sec
> 60 packets/sec with Integers results in:
– Aggregate data stream: 5,856,000 bps
– 6,000 Records/sec
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GE Consumer & Industrial
Multilin
June 3006
System Storage Requirements
• 100 PMU Model @ 60 Packets/sec:
– 250 Bytes/packet/PMU
– 25,000 Bytes/packet for 100 PMUs
– 1.5 MB/sec
– 90 MB/min
– 5.4 GB/hour
– 129.6 GB/day
– 3.9 TB/month
– 46.6 TB/year
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GE Consumer & Industrial
Multilin
June 3006
Data Analysis Needs:
• Synchrophasor Signature Analysis / Alarm
–Fault / Trip / Reclose
kV
–Fault / Trip / Lockout
kV
Time Scale: 30 Seconds/Division
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GE Consumer & Industrial
Multilin
June 3006
Indexing of Records
• Logical Index – Second of Century + Fraction of
Second
– Issue: Does not account for Leap Second
– Always assumes 31,536,000 sec/year
– Leap Second has same SOC as previous second
• Optional Indices:
– Time Atomic International- TAI
• TAI = UTC + 33 Seconds
– Global Positioning System – GPS
• GPS = UTC + 14 Seconds
• Start time: Jan 6, 1980
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GE Consumer & Industrial
Multilin
June 3006
Dynamic Synchrophasor Errors - 1
f (t ) = f 0 +
df
⋅ (t − t0 )
dt
f (t ) = power system frequency, in cycles per second
t = time, in seconds
df
= rate of change of frequency, cycles per second per second
dt
f 0 = power system frequency at the center of the window
t 0 = time, in seconds, at the center of the window = phasor time tag
The phase angle relative to phase angle and frequency at
center of the window is the integral of the frequency deviation:
1 df
θ (t ) − θ 0 = ⋅ ⋅ (t − t0 )2
2 dt
θ (t ) − θ 0 = phase angle deviation, cycles
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GE Consumer & Industrial
Multilin
June 3006
Dynamic Synchrophasor Errors - 2
The phase angle deviation relative to the center
value is quadratic. The largest value is at the beginning
and the end of the time window, given by:
1 df 2
∆θ = ⋅ ⋅ T
8 dt
∆θ = accumulated phase angle shift, cycles
df
= rate of change of frequency, Hz/second
dt
T = width of the sampling window, seconds
Example:
For df/dt = .7 Hz/sec and .016 sec. window
∆θ = .00002431 Cycles = .00875 degrees
20
GE Consumer & Industrial
Multilin
June 3006
Wide Area Measurement System for
Palo Verde Nuclear Power Plant
ARIZONA
LOCATION of SITES
Palo Verde
Transmission System
Devers
Westwing
Palo Verde
Arlington Valley
Hassayampa
Red Hawk
Jojoba
North Gila
Panda
PHOENIX
Kyrene
SRP Communication Performance
Data In
Data Out
End-to-End Messaging in 7ms!
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GE Consumer & Industrial
Multilin
June 3006
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GE Consumer & Industrial
Multilin
June 3006