Alberta Electric System Operator (AESO)
Oscillatory dynamics and corridor stress in the
Alberta electric system
North American SynchroPhasor Initiative March 2015
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
2
Alberta Grid - Topology
11,169
15,526
6513
1674
6553
514
272
22,322 km of transmission
• Intertie to Montana (230KV)
MT
3
Geographic map of Alberta
Voltage Levels:
• 500KV
• 240KV
• 138KV
• 69KV
4
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
5
Generation Locations
6
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
7
Load Schedule - Weekly
• AIES Weekly Winter Load Schedule
8
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)
9
PMU Locations
10
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
11
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
12
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.
13
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
14
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
Overview Status
Indicators
Individual stations
Angle Difference Alerts
BPA region
System Level Map
NWE region
Event History Viewer
Oscillatory Stability Management in PhasorPoint
Simultaneous multi-oscillation detection and
characterisation direct from measurements
Operations
Early warning of poor damping (two level alarms)
Measured P / f / δ
Unlimited oscillation frequency sub-bands
Individual alarm profiles for each sub-band
For each oscillation detected, alarm on:
mode damping and/or
1/F
Mode Frequency
MODE FREQUENCY
MODE DECAY
TIME time
Mode
decay
?)
Exp(-t/τ)
EXP(-t/
mode amplitude for
MODE PHASE
Mode Amplitude
Mode Phase
MODE AMPLITUDE
Wide area mode alarms
Mode locus plot with alarm
thresholds
Planning & Analysis, Plant Performance
A
Post-event analysis
Fast Modal Analysis:
Alarms
Dynamic performance baselining
Trend Modal Analysis:
Analysis
Dynamic model validation
Does not use system model
In operational use since 1995
Damping controller performance assessment
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
18
Dominant Modes – aggregated view
A very low frequency mode
WECC North-South Mode A
WECC North-South Mode B
Inter-area Dynamical Behavior
MW
Sub-bands or mode
boundaries
Higher frequency
Inter-area dynamics
in the power flow
1 month duration
Inter-area Dynamical Behavior
System Frequency
Little activity in
higher bands
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
Dominant modes
14
12
10
SB 1
SB 2
SB 3
SB 4
SB 5
SB 6
8
6
4
2
0
DR (%)
99.9%
DR (%)
99.5%
MW
99.9%
MW
99.5%
mHz
99.9%
mHz
99.5%
Example – Sub-band 2 [0.11 – 0.29Hz]
Event triggered oscillation
3 MW
Locus plot MW vs. Damping
Ratio
US – Canada flow
Alberta North-South Flow
Participation varies from signal to
signal
Example – Sub-band 2 [0.11 – 0.29Hz]
Locus plot mHz vs. Damping
Ratio
Locus plot mHz vs. Damping
Ratio
4.5 mHz
Participation about the same in all
frequency signals
MW angle Correlation
Syste
Co d t o
o
So
o
1600
1500
1400
1200
P
SoK
(MW)
1300
∆ θ / ∆ P (100MW) = 2.25 deg
1100
1000
900
v_genesee_330p_34415
- v_langdon_102s_34484
∠North
- South
linear
800
18
20
22
26
24
θarea(deg) →
28
30
32
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”
35
Angle (degree)
30
25
20
Never exported
during day-time
15
10
5
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
35
Angle (degree)
30
25
20
15
10
5
0
0
Hour →
Typical Angle behavior
24
Exporting
Importing
Sharp increase
in angle in
morning hours
23
22
Angle (degree)
21
Never exported
during day-time
20
19
18
17
16
Export condition angle is
always lower than “import”
condition
15
14
0
1
2
3
4
5
6
7
8
9
10
11
12
Hour
13
14
15
16
17
18
19
20
21
22
23