PDCWG Report to ROS
August 12, 2010
Sydney Niemeyer
In This Report
• PDCWG August 11 meeting items.• ERCOT Frequency Control Performance.
– CPS, RMS1 through July 2010.
• Update on Governor setting changes and impact on frequency profile.– Does it cost more to have a smaller governor
dead band?
• June 23, 2010 DCS event Interconnection Primary Frequency Response detail.
PDCWG Meeting August 11, 2010
• Nodal 24 hour LFC test review:– Regulation deployments utilize CPS 1 control
strategy. Is this appropriate for a single Balancing Authority Interconnection?
– QSE performance• GREDP• QSE AGC strategy
• Review July 2010 Frequency Events.• Wind Generator Primary Frequency Response
implementation.
• BAL-001-TRE-1 update on next draft posting.– LCRA, Eric Armke developing a manual on
using the Resource performance evaluation tool.
• Frequency Event review.– June 23, 2010 15:20 DCS event Primary
Frequency Response evaluation completed.– White paper review and discussion.
PDCWG Meeting August 11, 2010 continued
ERCOT CPS1 15 Minute Average - Monthly Score
0
20
40
60
80
100
120
140
160
180
200
Interval Ending
July-2010 CPS1 = 161.13
ERCOT CPS1 By Day - July 2010
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Day
NE
RC
CP
S1
0
3500
7000
10500
14000
17500
21000
24500
28000
31500
35000
38500
42000
45500
49000
52500
56000
59500
63000
66500
70000
ER
CO
T P
eak
En
erg
y
CPS1 Avg CPS1 ERCOT Pk Energy
161.13 Monthly CPS1 for ERCOT
ERCOT CPS2 - July 2010
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Day
NE
RC
CP
S2
- E
RC
OT
has
wai
ver
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
Cu
mu
lati
ve N
ER
C C
PS
2
CPS2 Avg CPS2
93.12 Monthly CPS2 for ERCOT
Daily RMS1
0.0100
0.0150
0.0200
0.0250
0.0300
0.0350
0.0400
1/1/2
000
7/1/2
000
1/1/2
001
7/1/2
001
1/1/2
002
7/1/2
002
1/1/2
003
7/1/2
003
1/1/2
004
7/1/2
004
1/1/2
005
7/1/2
005
1/1/2
006
7/1/2
006
1/1/2
007
7/1/2
007
1/1/2
008
7/1/2
008
1/1/2
009
7/1/2
009
1/1/2
010
7/1/2
010
of ERCOT Frequency
Daily RMS1
0.0100
0.0150
0.0200
0.0250
0.0300
0.0350
0.0400
1/1/
2004
4/1/
2004
7/1/
2004
10/1
/200
4
1/1/
2005
4/1/
2005
7/1/
2005
10/1
/200
5
1/1/
2006
4/1/
2006
7/1/
2006
10/1
/200
6
1/1/
2007
4/1/
2007
7/1/
2007
10/1
/200
7
1/1/
2008
4/1/
2008
7/1/
2008
10/1
/200
8
1/1/
2009
4/1/
2009
7/1/
2009
10/1
/200
9
1/1/
2010
4/1/
2010
7/1/
2010
100
110
120
130
140
150
160
170C
PS
1 A
vera
ge
100
110
120
130
140
150
160
170
Monthly Average 12 Month Rolling AverageTrend
ERCOT CPS1 Score
CPS1 12 Month Rolling Average = 147.04
ERCOT Frequency Profile
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
59.9
59.9
159
.92
59.9
359
.94
59.9
559
.96
59.9
759
.9859
.99 60
60.0
160
.02
60.0
360
.0460
.05
60.0
660
.07
60.0
860
.09
60.1
On
e M
inu
te O
ccu
ran
ces
2008
January through July of 2008 2008 First 7 months
2008 Jan thru July
0
20000
40000
60000
80000
100000
120000
59.9
59.9
159
.9259
.9359
.9459
.9559
.9659
.9759
.9859
.99 60
60.0
160
.0260
.0360
.0460
.0560
.0660
.0760
.0860
.09
60.1
MW
2008 MW Response of 0.036 db
439947.0 2008 MW Response of 0.036 db
MW-minute Response of a 600 MW Generator with Governor setting per ERCOT Protocols and Operating
Guides
Single 600 MW unit MW movement due to frequency.
600 MW Generator Governor Change
• Protocol and Guide settings:– 5% droop curve that steps to the 5% droop curve at
the dead-band.– Allows up to +/-0.036 Hz dead-band.
• Change Governor settings– 5% droop curve that is a straight line function from the
dead-band.– Decrease Governor Dead-band from:
• +/-0.036 Hz to +/-0.01666 Hz
Status as of August 5, 2010
• Units with Governors presently set with an intentional deadband less than or equal to +/-0.01666 Hz and droop curve with no step function.– 14,137 MW Total Capacity Identified by PDCWG
members.• 1690 MW Lignite• 5534 MW Coal• 3780 MW Combustion Turbine Combined Cycle• 1519 MW Combustion Turbine Simple Cycle• 1224 MW Steam Turbine – natural gas fired• 240 MW Hydro• 150 MW Wind Generators
ERCOT Frequency Profile Comparison
0
5000
10000
15000
20000
25000
30000
59.9
59.9
159
.92
59.9
359
.94
59.9
559
.96
59.9
759
.9859
.99 60
60.0
160
.02
60.0
360
.0460
.05
60.0
660
.07
60.0
860
.09
60.1
On
e M
inu
te O
ccu
ran
ces
2010 2008
January through July of each Year
January thru July 2008 0.036 db vs. 2010 0.016 db
0
20000
40000
60000
80000
100000
120000
59.9
59.9
159
.9259
.9359
.9459
.9559
.9659
.9759
.9859
.99 60
60.0
160
.0260
.0360
.0460
.0560
.0660
.0760
.0860
.09
60.1
MW
2008 MW Response of 0.036 db 2010 MW Response of 0.0166 db
439947.0
332694.6 2010 MW Response of 0.0166 db 24.38% Decrease in MW movement with lower deadband.
2008 MW Response of 0.036 db
MW Minute Movement of a 600 MW Unit @ 5% Droop
Same 600 MW unit MW movement due to frequency each year.
Benefits of Governor Change
• Generators move 24.38% less with lower dead-band compared to larger dead-band and poorer frequency control.
• Less maintenance on Generators.• Generators are more stable due to fewer and smaller
MW fluctuations.• Grid is more reliable due to higher probability that
frequency will be near 60 Hz at the time of a major event.
• Generators perform better during events since they are more stable before the event occurs.
• Potential fuel and emission savings.
June 23, 2010 DCS Event• Initial (Point B) Primary Frequency Response -486.77 MW/0.1 Hz.• Sustained (Point B+30 second) Primary Frequency Response
-416.33 MW/0.1 Hz.• Average Primary Frequency Response -458.85 MW/0.1 Hz.• Decreased performance at Point B+30 seconds due to 14,000 MW
of combustion turbine operating at HSL.– As turbine speed decreases with frequency, the mass flow through the
turbine decreases causing MW output to decrease.– Approximately 90 MW of total output was lost causing frequency to
decay from 59.775 Hz to 59.740 Hz.– This is a normal condition of combustion turbines operating at the
exhaust temperature limit of the turbine (HSL). Grid operators should be aware of this situation. In this scenario, if reserves are exhausted frequency would continue to decline instead of stabilizing.
Primary Frequency Response Evaluation
59.70
59.73
59.76
59.79
59.82
59.85
59.88
59.91
59.94
59.97
60.00
60.03
60.06
60.09
60.12
60.15
15:16 15:17 15:18 15:19 15:20 15:21 15:22 15:23 15:24 15:25 15:26
57550
57650
57750
57850
57950
58050
58150
58250
58350
58450
58550
58650
58750
58850
58950
59050
HZ ERCOT Load Total Generation ERCOT 60 HZ Calculated Load
6/23/10
Frequency, Load, & Generation
Generation Change -475 MW after 1253 MW tripped (net). PFR from governors = 778 MW
243 MW of LaaR Tripped (Load acting as a Resource)
252 MW of Load Dampening due to low frequency.
778 MW Pri Freq Response from Gen
246 MW of LaaR Response
252 MW of Load Dampening
1275 MW total Response.
1253 MW Tripped
22 MW error (load dampening, load growth or other data error)
June 23, 2010 DCS Event
59.70
59.72
59.74
59.76
59.78
59.80
59.82
59.84
59.86
59.88
59.90
59.92
59.94
59.96
59.98
60.00
60.02
60.04
60.06
60.08
60.10
15:1
8:50
15:1
9:00
15:1
9:10
15:1
9:20
15:1
9:30
15:1
9:40
15:1
9:50
15:2
0:00
15:2
0:10
15:2
0:20
15:2
0:30
15:2
0:40
15:2
0:50
15:2
1:00
15:2
1:10
15:2
1:20
15:2
1:30
15:2
1:40
15:2
1:50
15:2
2:00
15:2
2:10
Fre
qu
ency
- H
z
-1000
-900
-800
-700
-600
-500
-400
-300
-200
-100
0
MW
/0.1
Hz
Pri
mar
y F
req
uen
cy R
esp
on
se
Frequency Interconnection Frequency Response MW/0.1 Hz
Wednesday, June 23, 20101253
246
1007
Total MW Lost
MW Net Loss to Grid
LaaR Tripped
-458.85 Average Primary Frequency Response MW/0.1 Hz (BAL-001-TRE-1 measure)
-486.77 MW/0.1 Hz (Point B)
-416.33 MW/0.1 Hz (Point B+30 sec)
Poorer
Better
Secondary frequency decline.
59.70
59.73
59.76
59.79
59.82
59.85
59.88
59.91
59.94
59.97
60.00
60.03
60.06
60.09
60.12
60.15
15:16 15:17 15:18 15:19 15:20 15:21 15:22 15:23 15:24 15:25 15:26
57550
57650
57750
57850
57950
58050
58150
58250
58350
58450
58550
58650
58750
58850
58950
59050
HZ ERCOT Load Total Generation ERCOT 60 HZ Calculated Load
6/23/10
Frequency, Load, & Generation
688 MW Pri Freq Response from Gen
246 MW of LaaR Response
339 MW of Load Dampening
1273 MW total Response.
1253 MW Tripped
22 MW error (load dampening, load growth or other data error)
Approximately 90 MW output loss from combustion turbines operating at exhaust temperature limit when mass flow decreased during low frequency.
Approximately 14,000 MW of combustion turbines operating at HSL.
339 MW of Load Dampening due to new lower frequency.
Adequate reserves returned frequency to 60 Hz.