Centralized and Decentralized Control for Demand Response Project - - PowerPoint PPT Presentation

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Centralized and Decentralized Control for Demand Response

Energy and Environment Seminar University of Washing October 28th, 2010

Project team: Shuai Lu (PI) Harold Kirkham Nader Samaan Ruisheng Diao Marcelo Elizondo Chunlian Jin Ebony Mayhorn Yu Zhang Presented by: Shuai Lu

SLIDE 2

Outline

Concept of demand response Types of demand response programs Centralized and decentralized control in existing power systems Models to simulate the effects of demand response Comparing the two control philosophies Concluding remarks

SLIDE 3

Defining Demand Response

An earlier definition by FERC (2008)[1]:

A reduction in the consumption of electric energy by customers from their expected consumption in response to an increase in the price of electric energy or to incentive payments designed to induce lower consumption of electric energy.

Newer definition by FERC (2010)[2]:

“demand response” includes consumer actions that can change any part of the load profile of a utility or region.

smart appliances or devices that can respond automatically to the signals from utility or changes of power system condition. smart integration of changeable consumption with variable generation (wind and solar) manage demand as needed to provide grid services such as regulation and reserves

[1] Wholesale Competition in Regions with Organized Electric Markets, FERC Order No. 719, October 2008 [2] National Action Plan on Demand Response. FERC, June 2010

SLIDE 4

Type of Demand Response Programs

FERC DR Categorization [3]:

Type 1: dynamic pricing without enabling technologies (manual response to price signal) Type 2: dynamic pricing with enabling technologies (automatic response to price signal) Type 3: direct load control Type 4: interruptible tariffs Type 5: demand response programs operated by Independent System Operators (ISO) or utilities (providing various reserves for the system)

Another category that need to be added:

Type 6: autonomous load response to frequency and voltage

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[3] A National Assessment of Demand Response Potential, FERC, June 2009

SLIDE 5

Group DR Programs Based on Control Approaches

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Grouping Criteria Location where the information is from Local Center Location where the response decision is made Local Type 6 *Types 1 & 2 Central Types 3, 4 & 5

*If the price is generated through an auction process, in which both generation and demand submit bids in real time to get a market clearing price, then DR Type 1 and 2 could be considered decentralized control. Otherwise, if the price signal is “designed” by the system operator according to certain physical variables of the system, Type 1 and 2 could be considered a combination of centralized and decentralized control,

SLIDE 6

Centralized and Decentralized Control in Existing Power Systems

Purpose of controls

To maintain system voltages and frequency and other system variables within their acceptable limits, in response to normal load and generation variations as well as large disturbances.

Centralized controls

Generation scheduling and dispatch Automatic generation control for frequency regulation Real and reactive power flow adjustments to resolve congestions or reduce loss

Decentralized controls

Generator governor response Automatic voltage regulation Protection relays

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SLIDE 7

A Test Platform for Demand Response Control Approaches

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800 806 808 812 814 810 802 850 818 824 826 816 820 822 828 830 854 856 852 832 888 890 838 862 840 836 860 834 842 844 846 848 864 858

Modified IEEE 34 bus test feeder: Lumped loads were replaced by 147 detailed household load models; A load factor of 40% was assumed to determine the number of households.

SLIDE 8

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Water Heater Model

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24.000 19.200 14.400 9.6000 4.8000

• 0.0000

[h] 45.00006 45.00004 45.00002 45.00000 44.99998 44.99996 44.99994 test_blick: y1 24.000 19.200 14.400 9.6000 4.8000

• 0.0000

[h] 130.00 120.00 110.00 100.00 90.00 80.00 70.00 test_blick: Tw 24.000 19.200 14.400 9.6000 4.8000

• 0.0000

[h] 0.005 0.004 0.003 0.002 0.001 0.000

• 0.001

water heater_single: Total Active Power in MW myinputs(2) Date: 7/9/2010 Annex: /2 DIgSILENT

Water temperature Active power Water flow Electric power Water temperature

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Air Conditioning Model

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10000.0 8000.0 6000.0 4000.0 2000.0 0.0000 [s] PQ Measurement: Active Power in p.u. 10000.0 8000.0 6000.0 4000.0 2000.0

• 0.0000

[s] 84.00 83.00 82.00 81.00 80.00 House Common Model: To 10000.0 8000.0 6000.0 4000.0 2000.0

• 0.0000

[s] 3.00 2.00 1.00 0.00

• 1.00

House Common Model: p 10000 0 8000 0 6000 0 4000 0 2000 0 0 0000 [s] 79.00 78.00 77.00 76.00 75.00 74.00 73.00

Outdoor temperature Active power Indoor temperature Equivalent Thermal Parameters Circuit

SLIDE 10

10

Ten Types of House Load Representing Other Appliances

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site Residence Size Occupants_ number 28 2965 4 60 3156 3 100 2510 3 110 1518 2 250 1248 2 344 4119 6 361 2416 4 364 868 1 483 1988 2 500 2676 3

Information of the 10 types house

Other appliances data is taken from ELCAP load data set

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11

Single House Model

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A/C Water Heater Other appliances

SLIDE 12

Response Mechanisms in the Household Load Model

All demand responses come from A/C units and water heaters, i.e., thermostat-controlled loads. Centralized control

Proportional controllers for temperature settings adjustment Direct on/off control Communication delays are added

Decentralized control

Bang-bang controllers for frequency, voltage and price responses

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SLIDE 13

Simulations of the Two Control Approaches

Two types of DR functions were simulated:

Response to power system frequency dip Balancing generation and load (regulation and load following services)

The modified IEEE 34 bus feeder is connected to the IEEE 39 bus transmission system model to simulate frequency response. Regulation signal from a balancing authority and wind power derived from actual wind data were used to test balancing services.

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SLIDE 14

14 14

Project: Graphic: 39-bus_grid RMS-Simulation,balanced 10:000 s Nodes Line to Line Positive-Sequence Voltage, Magnitude [kV] Li G d P i i S V l M i d [ ]

Main

67.588 0.980 3.545

Station7/B7 94.895

0.949

• 5.534

Station6/B6 96.846

0.968

• 2.404

Station5/B5 96.399

0.964

• 3.159

Station4/B4 96.578

0.966

• 3.130

Station3/B3 99.319

0.993

• 1.878

Station2/B2 101.18..

1.012

• 0.543

Station29/B29 103.80..

1.038 9.201

Station28/B28 103.53..

1.035 6.314

• n1/B1 93.394

0.934

• 12.73..

Station27/B27 100.91..

1.009 0.974

Station26/B26 102.90..

1.029 2.367

Station25/B25 103.61..

1.036 1.652

Station24/B24 100.10..

1.001 4.855

Station23/B23 101.97..

1.020 13.489

Station22/B22

102.84.. 1.028 13.703

Station21/B21 100.09..

1.001 8.024

Station20/B20 102.99..

1.030 11.454

Station19/B19 100.52..

1.005 11.745

Station18/B18 99.429

0.994 0.014

Station17/B17 99.785

0.998 1.877

Station16/B16 99.466

0.995 4.385

Station15/B15 97.808

0.978 1.860

Station14/B1497.607

0.976

• 0.282

Station13/B13 98.225

0.982 0.924

Station12/B12 96.753

0.968 0.498

Station11/B11 97.894

0.979 0.177

Station10/B10 98.661

0.987 1.469

tation9/B9 91.945

0.919

• 14.99..

Station8/B8 94.367

0.944

• 6.522

2-W inding..

2.01 0.64 78.96

• 2.01
• 0.47

78.96

Load21

262.21 110.05

Load8

471.21 158.88

Load39

841.00 190.44

G ~ G10

250.38 348.98 28.63

G ~ G9

845.63 68.21 98.08

G ~ G8

608.67 73.71 101.01

G ~ G7

634.98 127.45 98.13

G ~ G6

785.23 361.17 110.10

G ~ G5

570.26

• 74.59

104.57

G ~ G4

713.06 362.37 111.87 740.65 345.69 102 17

G ~ G2

523.80 337.93 92.35

G ~ G1 Trafo9

845.63 68.21 92.27

• 840.1..

39.37 92.27

L28-29

• 356.3..

9.96 199.37 357.98

• 18.76

199.37

L26-28

• 154.2..
• 35.57

88.96 155.20

• 36.90

88.96

L25-26

38.55

• 53.33

36.92

• 38.49
• 0.71

36.92

L26-27

• 182.8..
• 129.3..

128.15 183.53 111.22 128.15

L17-27

• 86.30

56.97 71.06 86.47

• 87.18

71.06

Trafo8

608.67 73.71 92.32

• 606.5..

9.82 92.32

L2-25

• 416.9..

54.22 241.01 429.08

• 54.61

241.01

Trafo10

• 250.3..
• 318.5..

27.36 250.38 348.98 27.36

L16-24

143.75 98.58 102.78

• 143.6..
• 103.5..

102.78

Trafo6

• 785.2..
• 263.7..

103.20 785.23 361.17 103.20

L23-24

• 437.3..
• 10.86

252.32 441.56 40.83 252.32

Trafo7

634.98 127.45 88.75

• 633.0..
• 22.48

88.75

L22-23

46.47 81.25 62.27

• 46.41
• 99.66

62.27

L21-22

• 734.3..
• 131.5..

430.38 738.76 182.46 430.38

Trafo19-2..

• 47.72
• 234.1..

28.94 48.15 242.49 28.94

Trafo4

713.06 362.37 107.60

• 708.5..
• 269.8..

107.60

Trafo5

570.26

• 74.59

95.16

• 567.3..

133.26 95.16

L16-19

660.36 27.41 379.63

• 653.4..

26.69 379.63

L16-21

470.12 20.86 272.07

• 468.3..
• 16.30

272.07

L17-18

• 393.6..
• 9.75

228.69 394.78 9.52 228.69

L3-18

• 243.8..

5.51 142.42 244.53

• 18.57

142.42

L16-17

482.93

• 69.64

283.24

• 481.2..

77.66 283.24

L15-16

• 467.2..
• 125.8..

285.67 469.45 132.04 285.67

L14-15

• 163.7..
• 9.82

97.64 164.30

• 19.00

97.64

L13-14

• 203.3..
• 47.72

123.55 203.74 35.74 123.55

Trafo12-1..

• 17.79
• 44.59

5.87 17.83 45.67 5.87

Trafo11-1..

• 10.69

39.09 4.87 10.72

• 38.35

4.87

Trafo3

• 740.6..
• 206.6..

104.24 740.65 345.69 104.24

L10-13

221.79 76.81 138.76

• 221.5..
• 81.42

138.76

L10-11

518.85 129.79 313.97

• 517.6..
• 124.1..

313.97

L3-4

105.85 111.50 98.74

• 105.5..
• 127.0..

98.74

L4-5

4.53 7.02 11.99

• 4.53
• 19.49

11.99

L2-3

164.70 99.27 117.98

• 164.2..
• 119.2..

117.98

L1-2

• 492.6..
• 113.6..

312.52 502.61 165.01 312.52

L1-39

• 489.5..
• 100.9..

321.03 492.60 113.65 321.03

L9-39

352.98 28.98 232.90

• 351.4..
• 89.47

232.90

L8-9

356.37 49.53 222.40

• 352.9..
• 28.98

222.40

L5-6

• 482.9..
• 127.7..

299.19 483.47 130.62 299.19

L5-8

• 485.2..
• 129.1..

307.19 487.46 147.19 307.19

L7-8

342.92 78.65 215.01

• 342.3..
• 79.28

215.01

L6-7

557.42 178.59 350.74

• 555.2..
• 155.1..

350.74

L6-11

• 526.2..
• 73.63

316.79 528.37 85.06 316.79

Trafo2

514.63 333.35 89.34

• 514.6..
• 235.5..

89.34

L26-29

• 201.9..
• 38.73

116.53 204.18

• 46.98

116.53

L4-14

• 365.9..
• 51.77

220.95 367.12 57.54 220.95

Load4

466.93 171.83

Load3

302.21 2.25

Load18

149.15 28.32

Load25

215.92 45.50

Load26

134.11 16.40

Load27

269.19 72.33

Load28

201.11 26.95

Load29

277.96 26.37

Load24

293.61

• 87.72

Load15

302.97 144.86

Load16

313.04 30.73

Load23

237.91 81.32

Load20

615.05 100.88

Load12

7.07 82.94

Load31

9.17 4.59

Load7

212.29 76.53 DIgSILENT

Connection to test feeder Connection to test feeder Under- frequency event Under- frequency event Under- voltage event Under- voltage event

Simulation with Transmission network IEEE 39 bus system with 10 generators, total generation around 6.18 GW IEEE 34 bus system

SLIDE 15

Frequency Event Created

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10 20 30 40 50 60 59.2 59.4 59.6 59.8 60 60.2 Time (min) Frequency (Hz)

Frequency dip created by tripping generator 1, a large generator in the IEEE 39 bus system. Loads at buses 20, 8 and 39 were disconnected to simulate the recovery of the system frequency.

SLIDE 16

Frequency Response Provided by DR

16 10 20 30 40 50 60 1500 2000 2500 3000 3500 Total Feeder Load Time (min) Active Power (kW) DR to frequency event @ 6min Base case (no frequency event)

10 20 30 40 50 60 2000 2500 3000 3500 Total Feeder Load Time (min) Active Power (kW) DR to 5 degF temp setting change Base Case

Centralized control: Assuming 20 seconds delay by devices and 2 min delay by operators [4]. Decentralized control: Frequency thresholds 59.4 and 59.94 Hz.

[4] Demand Response Spinning Reserve Demonstration, LBNL-62761, Lawrence Berkeley National Laboratory, May 2007

Initialization period of A/C and water heaters

SLIDE 17

DR Following Regulation Signals

17 10 20 30 40 50 60 2200 2400 2600 2800 3000 3200 3400 Total Feeder Load Time (min) Active Power (kW) DR to regulation signal Base case 10 20 30 40 50 60

• 200

200 400 Regulation Signal Time (min) Active Power 10 20 30 40 50 60

• 300
• 200
• 100

100

Feeder Load Reduction

Time (min) Active Power

Feeder load Regulation signal and demand response providing regulation: Assuming 5 sec communication delay

SLIDE 18

DR Following Wind Power Variations

Water heaters and A/C units following wind power variation: Assuming 5 sec communication delay Control law: ΔTset = k•Reg With constraints on Tset and ΔTset

10 20 30 40 50 60 0.0105 0.011 0.0115 0.012 Regulation Signal Time (min) Active Power (pu) 10 20 30 40 50 60

• 1000
• 500

500 Feeder Load Reduction Time (min) Active Power (kW)

Regulation Signal Derived from Wind Power Output

SLIDE 19

Predictability of DR under Centralized Control

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10 20 30 40 50 60 2000 2200 2400 2600 2800 3000 3200 3400 Total Feeder Load Time (min) Active Power (kW) 1 degF temperature setting change 2 degF temperature setting change 3 degF temperature setting change 5 degF temperature setting change Base case

Feeder load change as a function of changes in temperature settings (ΔTset )

SLIDE 20

Predictability of DR under Centralized Control

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1 2 3 5 100 200 300 400 Temperature Setting Change (degF) Active Power (kW) Max Feeder Load Reduction

144.44 194.69 216.72 291.20

1 2 3 5 50 100 150 Temperature Setting Change (degF) Energy (kWh) Energy of temperature setting change from base case

34.03 56.66 74.06 113.33

Load reduction (max kW) as a function of changes in temperature settings Load reduction (kWh in 60-minute simulation) as a function of changes in temperature settings

SLIDE 21

Predictability of DR under Decentralized Control

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10 20 30 40 50 60 1500 2000 2500 3000 3500 Total Feeder Load Time (min) Active Power (kW) DR to frequency event @ 6min Base case (no frequency event)

Reduction caused by frequency response Reduction caused by voltage response

SLIDE 22

Comparison of the Characteristics of Two Control Philosophies

Response time

Decentralized control is much faster and suitable for improving system frequency response or resolving frequency and voltage stress of the system. Centralized control is slower and can not follow the fast changes of regulation signal but is suitable for load following service and spinning reserve.

Predictability

Response from decentralized control is more complicated and harder to predict. Response from centralized control is close-to-linear, in terms of load change vs. temperature setting adjustment

Reliability, complexity…

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SLIDE 23

Conclusion

Similar to how centralized and decentralized control philosophies are applied in the control of generation and transmission systems, it is expected that the advantages

• f both centralized control and decentralized control be

exploited to achieve the best performance of the smart grid.

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SLIDE 24

Acknowledgement

Research is funded by PNNL lab directed research and development (LDRD) program. The project team received support and help from the following PNNL colleagues:

Carl Imhoff Dave Chassin Jason Fuller Chellury Sastry

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Questions? Contact:

• Dr. Shuai Lu

Shuai.lu@pnl.gov

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