Grady, Brooks, NREL, 1/27/11

UT Pan Am

Austin

McDonald Observatory

400 miles

300 miles

Texas Synchrophasor NetworkData Validation and Mining

Austin

Majority of load is in the green rectangles, i.e. “Central ERCOT”

120V wall outlet at U.T. Austin, and 69kV 3Φ monitor at nearby Austin Energy Harris Sub

Wind Country

• Funding provided by EPRI

• Equipment provided by Schweitzer Engineering Labs

The Daily Screener

The Daily Screener, cont.

The Daily Screener, cont

Texas Synchrophasor Network PMU Daily Screener11041811 File Name = 110418 1E+0811041811 Full Scan Option11041811 Lines Read = 10800111041811 Number of Errors Dropouts and Messages = 0 errors 0 lines_with_dropouts 0 messages11041811 Dropout Ratio = 0.00%

11041811 PMU PMU Vbase Vmax Vmin Fmax Fmin dVmax dVmindAngm

axdAngm

in dFmax dFminAvg(Abs(

dF))Num

DropsNum

Recov11041811 1 Austin 79182 1.011 0.999 60.05 59.94 0.004 -9E-04 0.59 -0.71 0.004 -0.002 0.0001 0 011041811 2 Boerne_TX 0 11041811 3 CLOUD 0 11041811 4 HARRIS 66211 1.026 0.997 60.05 59.94 0.01 -0.002 0.59 -0.71 0.004 -0.003 0.00007 0 011041811 5 Houston_TX 0 11041811 6 McDonald 1P 40 1.043 1.003 60.05 59.93 0.009 -0.011 0.69 -1.21 0.015 -0.018 0.00019 0 011041811 7 Pullman_WA 0 11041811 8 UT Pan Am 79657 1.004 0.987 60.05 59.94 0.004 -0.004 0.62 -0.74 0.004 -0.004 0.00029 0 0

Hourly Summary File: PMU_Daily_Screener_11041811_Hourly_Report.csv

The Daily Screener, cont

Hourly Summary File: 11041811_Sixty_Minute_Angle_and_Freq_Report.csv

Frequency

59.90

59.95

60.00

60.05

60.10

0 500 1000 1500 2000 2500

Minute

UT

McD

Series3

The Daily Screener, cont

One-Minute Averages

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

McD

UTPA

Voltage Phase Angles, 1-Minute Averages

-20

-10

0

10

20

30

40

50

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

McD

UTPA

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 3.

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

Prof. Mack Grady, U.T. Austin

Voltage Phase Angles, 1-Minute Averages

-20

-10

0

10

20

30

40

50

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

McD

UTPA

1

1 1

Voltage Phase Angles, 1-Minute Averages

-20

-10

0

10

20

30

40

50

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

McD

UTPA

Zoom-In, 8 Hours Wide

Texas Synchrophasor Network News, April 18, 2011. Page 2 of 3.

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

Prof. Mack Grady, U.T. Austin

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

McD

UTPA

Sunday Morning, April 17, 2011

Texas Synchrophasor Network News, April 18, 2011. Page 3 of 3.

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

Prof. Mack Grady, U.T. Austin

Bus 7WINDBus 7WIND

500 km

Local conventional Pload,conv − Pgen,conv

Pexport

Thevenin Impedance jXTH

Central ERCOT

Vangle = 0

Vangle = δ

Wind MW Backdown. July 15, 2010. Thevenin Impedance Calculation, cont.

Use the Excel Solver with the 90 minutes of readings tominimize least-squared error and determine Xth

Lesson 4. You Can Estimate Thevenin Equivalent Impedances Across the Grid with Synchrophasors

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

De

gre

es

ERCOT’s graph of West-to-North P flow

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

Page 4 of 5

The Daily Screener, cont

The Daily Screener, cont

The Daily Screener, cont

The Daily Screener, cont

The Waveform Analyzer

The Waveform Analyzer, cont

Modal Analysis, cont.

Modal Analysis, cont.

Modal Analysis, cont.

Modal Analysis, cont.

Daily Screener for April 21, 2011, GMT