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CPS1 = * *Unofficial score.
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PDCWG Report to ROS
March 11, 2010Sydney Niemeyer
PDCWG Activities• Will meet March 10.
– Review February and remaining January disturbances.
– Operating Guide and Protocol synchronization.– Review and prepare report on Wind Event January
28, 2010.– PRR833 Primary Frequency Response Requirement
from Existing WGRs. – Submitted recommendation to the ROS.
– Updated Scope.• Next meeting April 7.
ERCOT CPS1 15 Minute Average - Monthly Score
0
20
40
60
80
100
120
140
160
180
Interval Ending
February-10 CPS1 = 150.46*
*Unofficial score.
*ERCOT CPS1 By Day - February 2010
010
20
30
40
5060
70
8090
100
110120130
140
150
160170
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
Day
03500
7000
10500
14000
1750021000
24500
280003150035000
385004200045500
49000
52500
5600059500
63000
66500
70000
SCPS1 Avg SCPS1 ERCOT Pk Load
150.46 Monthly CPS1 for ERCOT*
*ERCOT CPS2 - February 2010
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
Day
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
SCPS2 Avg SCPS2
90.60
Daily RMS1
0.0100
0.0150
0.0200
0.0250
0.0300
0.0350
0.0400
1/1/20
00
7/1/20
00
1/1/20
01
7/1/20
01
1/1/20
02
7/1/20
02
1/1/20
03
7/1/20
03
1/1/20
04
7/1/20
04
1/1/20
05
7/1/20
05
1/1/20
06
7/1/20
06
1/1/20
07
7/1/20
07
1/1/20
08
7/1/20
08
1/1/20
09
7/1/20
09
1/1/20
10
of ERCOT Frequency
January 28, 2010June 1, 2004
April 17, 2006
Daily RMS1
0.0100
0.0150
0.0200
0.0250
0.0300
0.0350
0.0400
1/1/20
04
4/1/20
04
7/1/20
04
10/1/
2004
1/1/20
05
4/1/20
05
7/1/20
05
10/1/
2005
1/1/20
06
4/1/20
06
7/1/20
06
10/1/
2006
1/1/20
07
4/1/20
07
7/1/20
07
10/1/
2007
1/1/20
08
4/1/20
08
7/1/20
08
10/1/
2008
1/1/20
09
4/1/20
09
7/1/20
09
10/1/
2009
1/1/20
10
February 18, 2010
100
110
120
130
140
150
160
170
CPS
1 Ave
rage
100
110
120
130
140
150
160
170
Monthly Average 12 Month Rolling Average Trend
ERCOT CPS1 Score
CPS1 12 Month Rolling Average = 142.35*
*Unofficial score
ERCOT CPS2 Score*
70
75
80
85
90
95
100
Oct-04Jan-05Apr-05Jul-05Oct-05Jan-06Apr-06Jul-06Oct-06Jan-07Apr-07Jul-07Oct-07Jan-08Apr-08Jul-08Oct-08Jan-09Apr-09Jul-09Oct-09Jan-10
Month
CPS
2
Series1 Trend (Monthly CPS2 Score)
*ERCOT as a single control area is exempt from CPS2. These scores are For Information Only
90.60
Comparing January 2009 vs January 2010 profile of frequency in 5 mHz bins
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
59.90
0
59.91
0
59.92
0
59.93
0
59.94
0
59.95
0
59.96
0
59.97
0
59.98
0
59.99
0
60.00
0
60.01
0
60.02
0
60.03
0
60.04
0
60.05
0
60.06
0
60.07
0
60.08
0
60.09
0
60.10
0
Jan-09Jan-10
Comparing February 2009 vs February 2010 profile of frequency in 5 mHz bins
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
59.90
0
59.91
0
59.92
0
59.93
0
59.94
0
59.95
0
59.96
0
59.97
0
59.98
0
59.99
0
60.00
0
60.01
0
60.02
0
60.03
0
60.04
0
60.05
0
60.06
0
60.07
0
60.08
0
60.09
0
60.10
0
Feb-09Feb-10
Comparison of Governor Deadband & Droop Settings of a
Single 600 MW UnitA 0.01666 Hz Deadband with a Straight Line Proportional 5% Droop Curve Compared to a 0.036 Hz Deadband with a “Step” Straight Line Proportional 5% Droop Curve from
the Deadband.
Sydney Niemeyer – February 9, 2010
Governor Settings Prior to November 2008
• 2008 Had Ten Months of Operation with no Governor setting changes.– ERCOT Operating Guides called for a maximum +/-
0.036 Hz deadband on Governors.– 5% Droop Setting with no clarification as to
implementation. With or without a step function at the deadband.
– To meet the 5% droop performance, Governors were encouraged to “step” into the 5% droop curve at the deadband.
Governor Settings After November 3, 2008
• Deadbands were decreased to +/-0.0166 Hz (1 rpm on a 3600 rpm turbine).
• The Droop curve implemented was a straight line proportional curve from the deadband eliminating any “step” function.
• Initially only 4 Unit’s Governors were changed. Total Capacity of 2486 MW or approximately 82.8 MW/0.1 Hz of Primary Frequency Response.
• The coordinated Boiler Control System implemented the same Droop curve and deadband as the turbine Governor.
• Additional Units changed their Governor settings throughout 2009 and 2010, mostly after July 2009.
Status as of March 1, 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.– 11,767 MW Total Capacity Identified by PDCWG
members.• 1690 MW Lignite• 4139 MW Coal• 3780 MW Combustion Turbine Combined Cycle• 1519 MW Combustion Turbine Simple Cycle• 399 MW Steam Turbine – natural gas fired• 240 MW Hydro
2008 Jan thru Oct
0
20000
40000
60000
80000
100000
120000
140000
160000
59.9
59.91
59.92
59.93
59.94
59.95
59.96
59.97
59.98
59.99 60
60.01
60.02
60.03
60.04
60.05
60.06
60.07
60.08
60.09 60
.1
MW
2008 MW Response of 0.036 db 2008 MW Response of 0.0166 db
591324.0
782765.9 MW Response of 0.0166 db
MW Response of 0.036 db
32.38% Increase in MW movement with lower deadband.
MW-Minute Primary Frequency Response of a 600 MW Unit To All Frequency Deviations During The First 10 Months of 2008
Min
ute
This compares the difference a single 600 MW unit would have experienced as a result of Primary Frequency Response if on-line the first 10 months of 2008 and had margin to move.
2008 Jan thru Dec
0
20000
40000
60000
80000
100000
120000
140000
160000
59.9
59.91
59.92
59.93
59.94
59.95
59.96
59.97
59.98
59.99 60
60.01
60.02
60.03
60.04
60.05
60.06
60.07
60.08
60.09 60
.1
MW
2008 MW Response of 0.036 db 2008 MW Response of 0.0166 db
662574.0
893164.2 MW Response of 0.0166 db
MW Response of 0.036 db
34.80% Increase in MW movement with lower deadband.
MW-Minute Primary Frequency Response of a 600 MW Unit To All Frequency Deviations in 2008
Min
ute
This compares the difference a single 600 MW unit would have experienced as a result of Primary Frequency Response if on-line all of 2008 and had margin to move.
2009 Jan thru Dec
0
20000
40000
60000
80000
100000
120000
140000
MW
2009 MW Response of 0.036 db 2009 MW Response of 0.0166 db
446244.0
692039.8 MW Response of 0.0166 db
MW Response of 0.036 db
55.08% Increase in MW movement with lower deadband.
However, the 692039.8 MW Response of the 0.0166 db unit is only 29465.8 MW more than the 2008 MW Response of the 0.036 db unit (662574.0 MW). A 4.45% increase with the benefit of the improved frequency profile.
The MW response of the 0.036 db unit decreased 216330.0 MW in 2009 from 2008. This is a 32.645% decrease in movement.
MW-Minute Primary Frequency Response of a 600 MW Unit To All Frequency Deviations in 2009
Min
ute The MW response
of the 0.0166 db unit decreased 201124.4 MW in 2009 from 2008. This is a 22.518% decrease in movement.
ERCOT Frequency Profile Comparison
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
One
Min
ute
Occ
uran
ces
2009 2008
525,600 One Minute Periods per Year 2009 Frequency Profile more “Normal” than 2008. Note: 2008 had two months of operation at the lower governor deadband settings (Nov & Dec).
ERCOT Frequency Profile 2008 and 2009
ERCOT Frequency Profile Comparison
0
500
1000
1500
2000
2500
3000
3500
4000
4500
59.9
59.91
59.92
59.93
59.94
59.95
59.96
59.97
59.98
59.99 60
60.01
60.02
60.03
60.04
60.05
60.06
60.07
60.08
60.09 60
.1
One
Min
ute
Occ
uran
ces
December 2009 January 2010 November 2009
December 2009 and January 2010 improved over typical (November 2009) performance.Several additional units changed their deadbands in
December 2009 and January 2010.
ERCOT Frequency Profile Had Additional Improvement in December 2009 and January 2010
MW-Minute Primary Frequency Response of a 600 MW Unit To All Frequency Deviations During January 2010
January 2010 Primary Frequency Response
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
59.9
59.91
59.92
59.93
59.94
59.95
59.96
59.97
59.98
59.99 60
60.01
60.02
60.03
60.04
60.05
60.06
60.07
60.08
60.09 60
.1
MW
Min
utes
MW Response of 0.036 db MW Response of 0.0166 db
53656.4
37384.0
MW Response of 0.0166 db
MW Response of 0.036 db
As the frequency profile continues to improve, the lower deadband unit provides 43.538% more MW movement than the larger deadband unit, but overall MW movement is less as the frequency deviations decrease in magnitude.
Conclusions• Clearly the MW-Minute Movement of a Unit with a lower
deadband setting is more than that of a larger deadband.• The MW-Minute movement of the lower deadband has a
gradual injection of Primary Frequency Response compared to the “step” implementation of the larger deadband.– Better Unit stability– Better Frequency stability
• As more Units implement the lower deadband and non-”step” droop curve, the frequency profile improves and the total MW-Minute movement of the grid decreases.
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