Compendium of Texas Synchrophasor Network Reports for 2011...

Compendium ofTexas Synchrophasor Network Reports

for2011 and 2012

Prof. Mack Grady Department of Electrical & Computer Engineering

Baylor UniversityWaco, Texas

[email protected]

September 20, 2013

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Texas Synchrophasor Network, WECC Event, Jan. 19, 2011

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Texas Synchrophasor Network Special Report, Prof. Mack Grady, U.T. Austin, Feb. 9, 2011 Page 1 of 9

The ERCOT Rolling Blackout

Wednesday, Feb. 2, 2011

• This new winter peak of 53334 MW was only 500 MW greater than the 2010 winter peak

• BUT, 5000 MW of generation was out of service due to the effect of extreme cold

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`` ERCOT Min and Max Frequency for Each Minute, Feb. 2, 2011

59.5

59.6

59.7

59.8

59.9

60.0

60.1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17Hour of Feb. 2, 2011

Freq Max

Min

West Texas Voltage Phase Angle wrt Central ERCOT for Each Minute, Feb. 2, 2011

-15

-10

-5

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17Hour of Feb. 2, 2011

Volta

ge A

ngle

Wind generation increasing

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ERCOT Min and Max Frequency for Each Minute, Feb. 2, 2011

59.5

59.6

59.7

59.8

59.9

60.0

60.1

4 5 6 7 8 9Hour of Feb. 2, 2011

Freq Max

Min

West Texas Voltage Phase Angle wrt Central ERCOT for Each Minute, Feb. 2, 2011

-15

-10

-5

0

5

10

15

20

25

4 5 6 7 8 9Hour of Feb. 2, 2011

Volta

ge A

ngle

Wind MW generation is not presently available on ERCOT’s public web site. However, by observing the voltage phase angle of West Texas with respect to U.T. Austin (i.e., central ERCOT), we believe that wind MW generation was low but on the rise at 5am when grid problems began, and that wind MW generation rose to moderate levels (approx. 10% of total generation) through the troubled 5am – 10am generation shortage period.

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2-minute wide frequency window at the lowest point

Corresponding West Texas phase angle with respect to central ERCOT

West Texas Phase Angle Increases with Wind Generation to Help Arrest the Freq Drop

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Frequency (Hz) of Main Oscillation Mode

0.70

0.75

0.80

0.85

3.5 4.5 5.5 6.5 7.5 8.5 9.5

One Hour Window Average, Centered on the Half-Hour

McDPanAm

Normalized Damping Ratio of Main Oscillation Mode

0.00

0.05

0.10

0.15

0.20

0.25

0.30

3.5 4.5 5.5 6.5 7.5 8.5 9.5


McDPanAm

Magnitude (Degrees) of Main Oscillation Mode (Top 1/4 Points Are Above This Value)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

3.5 4.5 5.5 6.5 7.5 8.5 9.5


McDPanAm

Decreasing Inertia

Increasing Inertia

More Damping

Less Damping

More Damping

Stronger Oscillation

Unusually low damping in Rio Grande Valley

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5:14 am

5:39 am

5:46 am

5:50 am

5:56 am

6:04 am

5:14 am

5:39 am

5:46 am

5:50 am

5:56 am

6:04 am

Progression of Ringdowns, 5 am to 6 amWest Texas Voltage Phase Angle with respect to Central Texas

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Average Hourly Price for Generation in ERCOT, $ / MWh, Feb. 1, 2, 3, 2011

0

200

400

600

800

1000

1200

Feb. 1 Feb. 2 (Rolling Blackout) Feb. 3

Dr. Mack Grady, U.T. Austin

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Average Hourly Load in ERCOT, GW, Feb. 1, 2, 3, 2011

0

10

20

30

40

50

60

70

80



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Hourly Price Multiplied by Load, $Millions / Day, Feb. 1, 2, 3, 2011(Is this what we were expecting from the Texas Nodal Market during an emergency?)

0

100

200

300

400

500

600

700

800



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Voltage Phase Angles Relative to Central ERCOT, 1-Minute Averages

-10

0

10

20

30

Five Hours Beginning 00:00 CDT, Sunday, April 17, 2011

McDUTPA

One Example, Sunday Morning, April 17, 2011

Texas Nodal Market Creates a New West Texas Oscillation Mode with Time Period ≈ 30 minutes

Prof. Mack Grady, U.T. Austin

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Voltage Phase Angles Relative to U.T. Austin (One-Minute Averages, 1800 Readings in Each Minute)

-60

-40

-20

0

20

40

60

0 24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384 408

Hour Beginning 00:00 CST, Sunday, March 27, 2011

McDUTPA

Voltage Phase Angles, 1-Minute Averages

-20

-10

0

10

20

30

40

50

24 Hours Beginning 18:00 CST, Saturday, April 2, 2011

McDUTPA

Zoom-In, 24 hours wide

1

1 1

1. Unusual large, slow angle rings I had not noticed before. Period ≈ 30 mins, 10º to 15º peak-to-peak.

Texas Synchrophasor Network News, April 18, 2011. Page 1 of 5.

Texas Nodal Market Has Created a New West Texas Oscillation Mode with Time Period ≈ 30 minutes


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-20

-10

0

10

20

30

40

50

24 Hours Beginning 18:00 CST, Saturday, April 2, 2011

McDUTPA

1

1 1


-20

-10

0

10

20

30

40

50

8 Hours Beginning 10:00 CST, Sunday, April 3, 2011

McDUTPA

Zoom-In, 8 Hours Wide


Texas Nodal Market Has Created a New West Texas OscillationMode with Time Period ≈ 30 minutes


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Voltage Phase Angles Relative to Central ERCOT, 1-Minute Averages

-10

0

10

20

30

Five Hours Beginning 00:00 CDT, Sunday, April 17, 2011

McDUTPA

Sunday Morning, April 17, 2011


Texas Nodal Market Has Created a New West Texas Oscillation Mode with Time Period ≈ 30 minutes


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McDonald Observatory Voltage Phase Angle Relative to Central ERCOT

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7 8 9 10 11 12

Hour of March 11, 2011

Deg

rees

ERCOT’s graph of West-to-North P flow

Texas SynchrophasorNetwork’s graph of West-to-Central ERCOT Voltage Angle

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UT Pan Am Voltage Phase Angle Relative to Central ERCOT

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7 8 9 10 11 12


Deg

rees

McDonald Observatory Voltage Phase Angle Relative to Central ERCOT

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7 8 9 10 11 12


Deg

rees

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Texas SynchrophasorNetwork’s graph of West-to-Central ERCOT Voltage Angle

Texas SynchrophasorNetwork’s graph of South-to-Central ERCOT Voltage Angle

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West Texas Voltage Phase Angle Advances 80+ Degrees in 6 Hours

Voltage Phase Angle Relative to UT Austin1-Minute Averages, Tuesday, April 26, 2011, Beginning 09:00 CDT

-50-40-30-20-10

01020304050

57 58 59 60 61 62 63 64 65 66 67

Hour of the Week, CDT

Deg

rees McD

PanAm

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Texas_Synchrophasor_Network_Observations_110505.doc

Page 1 of 1

Strong 30-Minute Oscillations Caused by Texas Nodal Market Price Fluctuations Continue to Break Out in West Texas Phase Angle

http://users.ece.utexas.edu/~grady/Texas_Synchrophasor_Network.html Texas Synchrophasor Network. Funding provided by EPRI, equipment provided by Schweitzer Engineering Labs, Utility members are Austin Energy and (new) Brazos Electric Cooperative, Waco.

Voltage Phase Angle Relative to UT Austin1-Minute Averages, Wednesday, May 4, 2011, Beginning 00:00 CDT

-20

-10

0

10

20

30

40

50

72 73 74 75 76 77 78 79 80 81 82 83 84


Deg

rees McD

PanAm

Voltage Phase Angle Relative to UT Austin1-Minute Averages, Sunday, May 1, 2011, Beginning 00:00 CDT

-20

-10

0

10

20

30

40

50

0 1 2 3 4 5 6 7 8 9 10 11 12


Deg

rees McD

PanAm

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Texas_Synchrophasor_Network_Observations_110510.doc

Page 1 of 1

Strong 30-Minute Oscillations Due to Texas Nodal Market Price Fluctuations Are Now Observed in South Texas Voltage Phase Angle

http://users.ece.utexas.edu/~grady/Texas_Synchrophasor_Network.html Texas Synchrophasor Network. Funding provided by EPRI, equipment provided by Schweitzer Engineering Labs, Utility members are Austin Energy and (new) Brazos Electric Cooperative, Waco.

Voltage Phase Angle Relative to UT Austin1-Minute Averages, Sunday, May 8, 2011, Beginning 00:00 CDT

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24


Deg

rees McD

PanAm

West Texas

South Texas

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Texas_Synchrophasor_Averages_Week_of_Jan_01_2012.doc users.ece.utexas.edu/~grady/Texas_Synchrophasor_Network.html

Page 1 of 2

McDonald Observatory Average Voltage Phase Angle1-Minute Intervals, Beginning Sunday, January 1, 2012

-60-50-40-30-20-1000102030405060

0 24 48 72 96 120 144 168

Hour of the Week, GMT

Deg

rees

wrt

UT

Aus

tin

Waco Average Voltage Phase Angle1-Minute Intervals, Beginning Sunday, January 1, 2012

-20

-10

00

10

20

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin

UT Pan Am Average Voltage Phase Angle1-Minute Intervals, Beginning Sunday, January 1, 2012

-20

-10

00

10

20

30

40

50

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin

ERCOT Power Flow North to South

ERCOT Power Flow South to North

South Texas Exports

South Texas Imports

West Texas Exports

West Texas Imports

370 miles

280 miles

100 miles

Straight-Line Miles

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Page 2 of 2

Harris 69kV Substation Minimum Frequency

1-Minute Intervals, Beginning Sunday, January 1, 2012

59.7

59.8

59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz

Harris 69kV Substation Maximum Frequency1-Minute Intervals, Beginning Sunday, January 1, 2012

59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz

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Page 1 of 2


-50-40-30-20-10001020304050

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin


-20

-10

00

10

20

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin


-10

00

10

20

30

40

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin



South Texas Exports

South Texas Imports

West Texas Exports

West Texas Imports

370 miles

280 miles

100 miles

Straight-Line Miles

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Page 2 of 2

Harris Minimum Frequency1-Minute Intervals, Beginning Sunday, January 8, 2012

59.7

59.8

59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz

Harris Maximum Frequency1-Minute Intervals, Beginning Sunday, January 8, 2012

59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz

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Page 1 of 2


-40-30-20-100010203040506070

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin


-20

-10

00

10

20

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin


-20

-10

00

10

20

30

40

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin



South Texas Exports

South Texas Imports

West Texas Exports

West Texas Imports

370 miles

280 miles

100 miles

Straight-Line Miles

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Page 2 of 2


59.7

59.8

59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz


59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz

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Page 1 of 2


-60-50-40-30-20-1000102030405060

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin


-20

-10

00

10

20

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin


-20

-10

00

10

20

30

0 24 48 72 96 120 144 168


Deg

rees

wrt

UT

Aus

tin



South Texas Exports

South Texas Imports

West Texas Exports

West Texas Imports

370 miles

280 miles

100 miles

Straight-Line Miles

Profs: Mack Grady and Surya Santoso at U.T. Austin, Jaime Ramos at U.T. Pan American

Equipment and Engineering Support: Donated by Schweitzer Engineering Labs.

Utility Partners: Austin Energy, Brazos Electric Power Coop Friends: Thanks to Schweitzer, we are rich in equipment. However, to be honest, we are out of cash. There is no better way to support a future power engineer than through this project. You can do that by sending a check to any one of us, made out to our respective university. Make sure the phrase “to support Prof XXX’s synchrophasor research” is somewhere on the check. Thank you.

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Page 2 of 2


59.7

59.8

59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz


59.9

60.0

60.1

0 24 48 72 96 120 144 168


Hz

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Texas_Synchrophasor_Network_Jan_29_2012.doc. Events automatically detected by our PMU_Waveform_Analyzer.

Page 1 of 1

Comments – Synchronized rms voltage measurements are also useful. The top graph shows consecutive deep rms voltage sags at UT Pan Am (red). The lower graph shows a zoom-in of the Harris 69 substation (adjacent to UT Austin campus), and Waco. We used the Harris substation voltage instead of UT Austin because it was less choppy. McDonald voltage showed no response. Point spacing is 30 points per second. Though low in magnitude, the voltage sags are clearly visible at Austin and Waco. Synchronization confirms the timing of the sag points.

Voltage Sag, 1/29/2012, 19:43:00 GMT

0.75

0.80

0.85

0.90

0.95

1.00

1.05

2.5 3.0 3.5 4.0 4.5

Seconds

Vrm

s, p

er u

nit

Harris 69

UT Pan Am

Waco

Zoom-In of Voltage Sag, 1/29/2012, 19:43:00 GMT

0.997

0.998

0.999

1.000

1.001

2.5 3.0 3.5 4.0 4.5

Seconds

Vrm

s, p

er u

nit

Harris 69

Waco

370 miles

280 miles

100 miles

Straight-Line Miles

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Texas Synchrophasor Network, Sunday, Feb. 19, 2012, 03:17 GMT740 MW Trip Causes ERCOT Frequency to Drop to 59.73 Hz

ERCOT Load = 33301 MW

Two minute window

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