Alberta Electric System Operator (AESO)
Oscillatory dynamics and corridor stress in the Alberta electric system
North American SynchroPhasor Initiative March 2015
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Agenda
• Alberta Electrical System Overview
• Operational Challenges
• WISP Participation
• HVDC integration
• Synchrophaser monitoring software
• Integration into control room/EMS
• Data Mining Overview
• Results of Data Mining Project
Alberta Grid - Topology
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11,169
15,526
6513 1674
6553
514 272
22,322 km of transmission
• Intertie to Montana (230KV) MT
Geographic map of Alberta
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Voltage Levels:
• 500KV
• 240KV
• 138KV
• 69KV
Load vs Generation Locations
• Fort McMurray Oil Sands in NE of province (BTF Generation)
• Major load centers in Calgary(South) and Edmonton (Center)
• Major Generation in Center West of province and FT Mc Murray areas
• 1.5GW of wind in south of province
• 500KV intertie to BCH located east of Calgary (South)
• 230KV intertie to Montana located at southern most point of province
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Generation Locations
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Operational Challenges
• 240KV backbone south to central and central to north
• Wind ramp in the province can incur issues (WPRM)
• Intertie 500KV from south and 240KV to Montana – WECC Loop Model to reduce contingencies from loop flows
• Large volume of North to south power transfers
• Industrial load
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Load Schedule - Weekly
• AIES Weekly Winter Load Schedule
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WISP Participation
• The AESO as part of the Wisp Program installed SEL Phasor Measurement Units at 5 location in Alberta
– Bennett ( 500KV tie to BCH)
– Picture Butte (240KV tie to Montana)
– Langdon (240KV SVC and (4) 240KV Lines)
– Sundance (Generator and 240KV Lines)
– Genesee (Generator)
• Future Locations (HVDC)
– Sunnybrook (Northwest converter station)
– Crossings (Southwest converter station)
– Newell (Southeast converter station)
– Heathfield (Northeast converter station)
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PMU Locations
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Purpose
• Drivers – Eastern Alberta Transmission Line (485KM - 500KV DC) will
extend from the southeast of Alberta to the northeast.
– Western Alberta Transmission Line (347KM – 500KV DC) will extend from the south of Alberta to the central west
– Expected in service date in 2015
• As part of the HVDC integration we will be installing PMU’s at both ends of the HVDC lines
• AESO pursued an integrated real time toolset to provide real time monitoring and early warning capability of transient stability issues
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ALSTOM Phasor Point/OpenPDC
• The ALSTOM Phasor Point was selected for the Real time monitoring tool to be integrated as a stand-alone application
• OpenPDC (GPA) was selected as the Data Concentrator for Phasor data
• Data connections with external entities – WECC
– Northwest Energy (Montana)
– BC Hydro
– Bonneville Power Administration
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Control Room/EMS Integration
• Phasorpoint Sandbox was delivered from ALSTOM in 2013 – Used for application training and proof of concept
• Production standalone Phasorpoint integration – Integrated with the OpenPDC to gather real time PMU data
from remote PMU sites
– Engineering support staff used to gain knowledge of the product
– Available outside the control room to operators to gain familiarity with
• No Control Room consoles have been deployed with the Phasorpoint software at this time, expected to be completed by HVDC commissioning.
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Problem
• Determine ‘How To Operate with Phasor data in Real Time”
• Determine what are acceptable limits for the PMU fluctuation vs. what is considered an alarm and what is considered an actionable event for the SC
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Data Mining with Alstom
Dynamic Performance Baselining • Identify oscillatory modes
– Estimate where the modes are “observable”.
– Typical amplitude and damping levels.
• Suggest alarm/alert limits in e-terraPhasorPoint
Angle Baselining • Identify distribution of angle differences across critical transfer paths
– Under different operational conditions
– Correlate MW transfers
– Change in angular separation for every 100MW change in power
AESO PhasorPoint System
NWE region
BPA region
Angle Difference Alerts
Overview Status Indicators
System Level Map
Event History Viewer
Individual stations
Oscillatory Stability Management in PhasorPoint
1/F MODE FREQUENCY
MODE AMPLITUDE
A
MODE DECAY TIME
EXP(-t/ ? )
MODE PHASE
Mode Frequency
Mode Amplitude
Mode decay time
Mode Phase
Exp(-t/τ)
Measured P / f / δ
Simultaneous multi-oscillation detection and characterisation direct from measurements
For each oscillation detected, alarm on:
mode damping and/or
mode amplitude for
Operations
Planning & Analysis, Plant Performance
Unlimited oscillation frequency sub-bands
Individual alarm profiles for each sub-band
In operational use since 1995 Does not use system model
Post-event analysis
Dynamic model validation
Damping controller performance assessment
Dynamic performance baselining
Early warning of poor damping (two level alarms)
Fast Modal Analysis: Alarms
Trend Modal Analysis: Analysis
Wide area mode alarms Mode locus plot with alarm thresholds
So ……
• Needs to be information for the Operator
• Great data does not mean anything if we cant take action
• Napsi challenge
• Without RT just theoretical
• Huge value in decision making, financial and reliable
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Dominant Modes – aggregated view
A very low frequency mode
WECC North-South Mode A
WECC North-South Mode B
Inter-area Dynamical Behavior
Higher frequency Inter-area dynamics
in the power flow
Sub-bands or mode boundaries
MW
1 month duration
Inter-area Dynamical Behavior
Little activity in higher bands
System Frequency
1 month duration
Modes and Sub-band Boundaries
Mode (Hz) Lower Bound
Higher Bound
0.05 SB1 0.00 0.11
0.23 SB2 0.11 0.29
0.42 SB3 0.29 0.46
0.62 SB4 0.46 0.70
0.83 SB5 0.70 0.89
-NA- SB6 0.89 1.10
-NA- SB7 1.10 1.49
Summary – Damping Ratio by Sub-bands
0
2
4
6
8
10
12
14
DR (%)99.9%
DR (%)99.5%
MW99.9%
MW99.5%
mHz99.9%
mHz99.5%
SB 1SB 2SB 3SB 4SB 5SB 6
Dominant modes
Example – Sub-band 2 [0.11 – 0.29Hz]
US – Canada flow
Alberta North-South Flow
3 MW
Participation varies from signal to signal
Event triggered oscillation Locus plot MW vs. Damping Ratio
Example – Sub-band 2 [0.11 – 0.29Hz]
4.5 mHz
Locus plot mHz vs. Damping Ratio
Participation about the same in all frequency signals
Locus plot mHz vs. Damping Ratio
MW angle Correlation
18 20 22 24 26 28 30 32800
900
1000
1100
1200
1300
1400
1500
1600
θarea(deg) →
P SoK
(MW
)
Syste Co d t o o So o
v_genesee_330p_34415 - v_langdon_102s_34484 linear
∆ θ / ∆ P (100MW) = 2.25 deg
∠North - South
Summary
• Recommended Limits – For oscillation monitoring
– For monitoring angle-pairs
• Derived from data statistics and field expertise • Minimizes false alarms • Much lower hysteresis to be able to detect events! • No significant difference in angle base-lines for
– Weekdays and week-ends
– Net Import vs. Net Export
• Should be repeated with HVDC system in-service.
Thank you
“Importing” vs. “Exporting”
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 230
5
10
15
20
25
30
35
Ang
le (d
egre
e)
Never exported during day-time
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 230
5
10
15
20
25
30
35
Hour →
Ang
le (d
egre
e)
Typical Angle behavior
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 2314
15
16
17
18
19
20
21
22
23
24
Hour
Ang
le (d
egre
e)
ExportingImporting
Export condition angle is always lower than “import” condition
Sharp increase in angle in
morning hours
Never exported during day-time