1 presentation mit november 14, 2011 metering issues taskforce (mit) elimination of time error...
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1 Presentation MITNovember 14, 2011
Metering Issues Taskforce (MIT)
Elimination of Time Error Correction Potential Impact on Wholesale Settlements
2 Presentation MITNovember 14, 2011
Background
• NERC Operating Committee (OC) directed the Resources Subcommittee (RS) to develop a field trial to eliminate manual Time Error Corrections
• What is Time Error? – Difference between NIST time and a clock driven by frequency
• If average frequency is 60Hz, Time Error will be zero• If frequency is 0.01Hz high (low), a clock will gain (lose) 0.6 seconds an hour
• What are Manual Time Error Corrections ?– Minor coordinated adjustments to frequency– One Reliability Coordinator in each Interconnection is designated “Time Monitor”– ERCOT Nodal Operating Guide Section 2.2.9.1 deals with time error
• When time error is equal to or greater than ±3 seconds, ERCOT may initiate a time correction
• Correction may end when error is less than ±0.5 seconds or when system events mandate termination
• Time correction may be postponed if it is determined that load patterns in immediate future will result in desired time correction
3 Presentation MITNovember 14, 2011
Impact of Elimination of Time Error Correction on Wholesale Settlements
• Assume that ERCOT Polled Settlement (EPS) meters will be synchronized with NIST clock
• Potential effect on wholesale settlements is analyzed for following: – Flat load– Price responsive load and/or demand responsive load
• Different MW load connected to the IDR meter-100 to 1150 MW • Different delays (lag and lead)- 15 sec, 30 sec and 45 sec• Different price levels- $200 to $3000 /MWH
– Aggregate IDR load in grid
• Maximum allowed time error according to ERCOT Nodal Protocol 10: Metering– For TDSP meters: ±5% of settlement interval (15 min) or 45 sec of NIST clock– For EPS meters : ±1% of settlement interval (15 min) or 9 sec of NIST clock– ERCOT production servers are maintained within ±1 sec of NIST clock
• Wholesale price calculations synchronized within ±1 sec of NIST clock for each settlement interval
• No analysis conducted for retail settlements– Results contingent on contracts and specific load characteristics
4 Presentation MITNovember 14, 2011
-Delayed IDR Clock -NIST Clock
Interval 1 Interval 2 Interval 3 Interval 4 Interval 5
30 sec delay
16:45:0016:30:00
150 MW 150 MW
$35/ MWH $35/ MWH
0 MW
37.5 MWH 36.25 MWH 0 MWH 1.25 MWH 37.5 MWH
16:15:0016:00:00
$1000/ MWH
Price/Demand Responsive LoadIDR slower than NIST clock by 30 sec, 150 MW load
5 Presentation MITNovember 14, 2011
Price/Demand Responsive LoadExcel Worksheet for Calculation
Fill in the following values: 1. Load (MWH)
2. Time deviation (sec)
3. Price ($/MWH )in each interval
LR Load (MW)LR Load (MWH-15 min
interval)Meter clock deviation from
NIST (sec)150.00 37.5 30
Price in Interval 1($/MWH) Price in Interval 2($/MWH) Price in Interval 3($/MWH) Price in Interval 4($/MWH) Price in Interval 5($/MWH)$35.00 $35.00 $1,000.00 $1,000.00 $35.00
Load in Interval 1(MWH) Load in Interval 2(MWH) Load in Interval 3(MWH) Load in Interval 4(MWH) Load in Interval 5(MWH)37.5 36.25 0 1.25 37.5
Total Price in Interval 1($) Total Price in Interval 2($) Total Price in Interval 3($) Total Price in Interval 4($) Total Price in Interval 5($)$1,312.50 $1,268.75 $0.00 $1,250.00 $1,312.50
6 Presentation MITNovember 14, 2011
Price/Demand Responsive LoadIDR slower than NIST clock by 30 sec, 150 MW load
MWH in Interval Price in Interval
($/MWH)
Total Price in Interval ($)
Expected MWH (w/o clock lag)
Actual MWH (with clock lag)
Expected Price (w/o clock lag)
Actual Price (with clock lag)
Interval 1 37.5 37.5 $35 $1,312.5 $1,312.5
Interval 2 37.5 36.25 $35 $1,312.5 $1,268.75
Interval 3 0 0 $1000 $0 $0
Interval 4 0 1.25 $1000 $0 $1,250.00
Interval 5 37.5 37.5 $35 $1,312.5 $1,312.5
Total Price $3,937.50 $5,143.75
Net Loss $1,206.25
7 Presentation MITNovember 14, 2011
Price/Demand Responsive LoadEffect of Time Delay at Different Load Levels
Price in Interval 4: $1000/MWHPrice in Interval 2: $35/MWH
Note: Net losses calculated over entire 5
interval event
Savings in Interval 2
$0
$100
$200
$300
$400
$500
$600
50 100 150 200 500 1150
MW Load
15 sec delay
30 sec delay
45 sec delay
$0
$2,000
$4,000
$6,000
$8,000
$10,000
$12,000
$14,000
$16,000
50 100 150 200 500 1150
MW Load
Losses in Interval 415 sec delay
30 sec delay
45 sec delay
$0
$2,000
$4,000
$6,000
$8,000
$10,000
$12,000
$14,000
$16,000
50 100 150 200 500 1150
MW Load
Net Losses 15 sec delay
30 sec delay
45 sec delay
8 Presentation MITNovember 14, 2011
Net Losses
$0
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
$7,000
$8,000
50 100 150 200 500 1150
MW Load
15 sec delay
30 sec delay
45 sec delay
$0
$5,000
$10,000
$15,000
$20,000
$25,000
$30,000
$35,000
$40,000
$45,000
50 100 150 200 500 1150
MW Load
Net Losses 15 sec delay
30 sec delay
45 sec delay
Net Losses
$0
$500
$1,000
$1,500
$2,000
$2,500
50 100 150 200 500 1150
MW Load
15 sec delay
30 sec delay
45 sec delay
Net Losses
$0
$2,000
$4,000
$6,000
$8,000
$10,000
$12,000
$14,000
$16,000
50 100 150 200 500 1150
MW Load
15 sec delay
30 sec delay
45 sec delay
Price/Demand Responsive LoadEffect of Time Delay at Different Price Levels
Price in Interval 4: $200/MWH Price in Interval 4: $500/MWH
Price in Interval 4: $1000/MWH Price in Interval 4: $3000/MWH
Note: Net losses calculated over entire 5 interval event
9 Presentation MITNovember 14, 2011
-Accelerated IDR Clock -NIST Clock
Interval 1 Interval 2 Interval 3 Interval 4 Interval 5
30 sec delay
16:45:0016:30:00
150 MW 150 MW
$35/ MWH $35/ MWH
0 MW
37.5 MWH36.25 MWH0 MWH1.25 MWH37.5 MWH
16:15:0016:00:00
$1000/ MWH
Price/Demand Responsive LoadIDR faster than NIST clock by 30 sec, 150 MW load
Losses and savings intervals interchanged
Values remain same
10 Presentation MITNovember 14, 2011
-Delayed IDR Clock -NIST Clock
Interval 1 Interval 2 Interval 3
30 sec delay
10,000 MWH
Aggregate IDR Load IDR slower than NIST clock by 30 sec
10,200 MWH
10,400 MWH
Energy Recorded by IDR In Interval 2 = Energy Consumed in Interval 2 +
Metered Energy Shifted from Interval 3 to 2 -Metered Energy Shifted from Interval 2 to 1
Note: IDR accounts for 70% of total grid load
10,206.67 MWH = 10,200.00 MWH + 346.67 MWH – 340.00 MWH
11 Presentation MITNovember 14, 2011
- Accelerated IDR Clock -NIST Clock
Interval 1 Interval 2 Interval 3
30 sec delay
10,000 MWH
Aggregate IDR Load IDR faster than NIST clock by 30 sec
10,200 MWH
10,400 MWH
Energy Recorded by IDR In Interval 2 = Energy Consumed in Interval 2 +
Metered Energy Shifted from Interval 1 to 2 -Metered Energy Shifted from Interval 2 to 3
Note: IDR accounts for 70% of total grid load
10,193.33 MWH = 10,200.00 MWH + 333.33 MWH – 340.00 MWH
12 Presentation MITNovember 14, 2011
Generation
8000
10000
12000
14000
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Aggregate IDR Load Example: June 09, 2011IDR slower than NIST clock by 30 sec
Shift in Interval Load
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Average Shift in Interval Load Due to IDR Delay: 0.0006%
Average UFE: 0.4000%
% UFE
-0.80%
-0.40%
0.00%
0.40%
0.80%
1.20%
1.60%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
% UFE
% shift in interval load
% Shift in Interval Load
-0.08%
-0.06%
-0.04%
-0.02%
0.00%
0.02%
0.04%
0.06%
0.08%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
13 Presentation MITNovember 14, 2011
Generation
6500
7500
8500
9500
10500
11500
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Aggregate IDR Load Example: April 21, 2011 IDR slower than NIST clock by 30 sec
Shift in Interval Load
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Average Shift in Interval Load Due to IDR Delay: 0.0014%
Average UFE: 0.3606%
% Shift in Interval Load
-0.08%
-0.06%
-0.04%
-0.02%
0.00%
0.02%
0.04%
0.06%
0.08%
0.10%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
% UFE
-1.60%
-0.80%
0.00%
0.80%
1.60%
2.40%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
% UFE
% shift in interval load
14 Presentation MITNovember 14, 2011
Generation
5500
6500
7500
8500
9500
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Aggregate IDR Load Example: Dec 21, 2010IDR slower than NIST clock by 30 sec
Shift in Interval Load
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Average Shift in Interval Load Due to IDR Delay: 0.0004%
Average UFE: -1.2298%
% UFE
-4.00%
-3.20%
-2.40%
-1.60%
-0.80%
0.00%
0.80%
1.60%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
% UFE
% shift in interval load
% Shift in Interval Load
-0.08%
-0.06%
-0.04%
-0.02%
0.00%
0.02%
0.04%
0.06%
0.08%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
15 Presentation MITNovember 14, 2011
Generation
8000
10000
12000
14000
16000
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Aggregate IDR Load Example: Jul 8, 2011IDR slower than NIST clock by 30 sec
Average Shift in Interval Load Due to IDR Delay: 0.0014%
Shift in Interval Load
-12.00
-7.00
-2.00
3.00
8.00
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Average UFE: 1.0757%
% Shift in Interval Load
-0.08%
-0.06%
-0.04%
-0.02%
0.00%
0.02%
0.04%
0.06%
0.08%
0.10%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
% UFE
-0.50%
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
16 Presentation MITNovember 14, 2011
Generation
8000
10000
12000
14000
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Aggregate IDR Load Example: Feb 2, 2011IDR slower than NIST clock by 30 sec
Average Shift in Interval Load Due to IDR Delay: 0.0007%
Shift in Interval Load
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
MW
H
Average UFE: 1.9799%
% Shift in Interval Load
-0.08%
-0.06%
-0.04%
-0.02%
0.00%
0.02%
0.04%
0.06%
0.08%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
% UFE
-6.00%
-4.00%
-2.00%
0.00%
2.00%
4.00%
6.00%
8.00%
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96
settlement interval
17 Presentation MITNovember 14, 2011
Summary
• Observations of this study are as follows: – Flat load
• No Impact
– Price/demand responsive load• Potential impact. Will depend on site operating procedures and load characteristics• IDR clock error combined with variations in price of electricity will result in savings in
one interval, with losses in other
– Aggregate IDR load• Meter clock error up to 45 seconds has minimal impact on aggregate IDR load used in
wholesale settlements • IDR clock error combined with variations in price of electricity will result in savings in
one interval, with losses in other
• Note: Study of impact of elimination of time error correction on retail settlements or an individual market participant has not been performed. Each individual party should carry out their own study based on their specific load characteristics
18 Presentation RMSAug 17, 2011
Questions?