2019 brake tests: initial analysis - 2019 brake tests initial analysis.pdfobat also includes varpro...
TRANSCRIPT
2019 Brake Tests:Initial Analysis
Jim Follum
September 19, 2019
PNNL-SA-147531
2
• BPA has performed system tests over the past decade
• Large disturbances excite system dynamics, providing valuable data
▪ Insertion of Chief Joseph Dynamic Braking Resistor
▪ Probing signal injection modulates flow on the PDCI
Background
Chief Joseph Dynamic Braking Resistor. Image courtesy of BPA.
3
Test Series A: Calibration Checks on PDCI Probing Signals
Step A0 [16:10] Celilo instrumentation check using +20MW waveform (10 seconds) and -20 MW (10 seconds). Check proper function of PSG using Celilo/Sylmar DC metering.
Step A1 [16:15] Calibration check on MSF-1/5/2/100 for ±20 MW noise probing for a duration of one period (100 seconds). Adjust PSG scaling if needed.
Step A4 [16:30] Apply MSF-0.1/4x for ±20 MW single frequency sine wave for four cycles. (1 period)
Step A5 [16:35] Apply MSF-0.3/4x for ±20 MW single frequency sine wave for four cycles. (1 period)
Step A6 [16:40] Apply MSF-0.7/4x for ±20 MW single frequency sine wave for four cycles. (1 period)
Step A7 [16:45] Apply MSF-1.0/4x for ±20 MW single frequency sine wave for four cycles. (1 period)
Test Series B: Noise Probing
Step B1 [17:10] Measurement of ambient noise conditions
Step B2 [17:30] Apply a +20 MW MSF-1/5/2/100 for a duration of 12 periods (20 minutes).
Test Series C: Chief Joseph brake insertion (Afternoon)
Step C1 [21:14] Apply Chief Joseph braking resistor
Step C2 [21:20] Apply a +20 MW MSF-1/5/2/100 for a duration of 12 periods (20 minutes).
Step C3 [21:44] Apply Chief Joseph braking resistor
Notes:
• (Times are in UTC and reflect the testing plan)
• PSG = Probing Signal Generator
• MSF = Multi-Sine Fitted
• Tests conducted May 7 and August 21, 2019
• Presented results focus on Test Series C
Testing Procedure
4
Big Eddy – Celilo MW FlowSteps A0-A1: Instrumentation/Calibration Checks
5
Big Eddy – Celilo MW FlowSteps A4-A7: Single Frequency Sinusoids
6
Big Eddy – Celilo MW FlowStep B2: Noise Probing
Full Signal
(12 periods)
Zoomed In
Frequency Domain
7
Derived Frequency at all SubstationsSteps C1 and C3: Brake Insertions
8
• Archive Walker
▪ Ingests, processes, and exports PMU data
▪ Detects ringdowns
▪ Implements mode meter
• Oscillation Baselining and Analysis Tool (OBAT)
▪ Performs ringdown analysis
▪ Displays mode shape geographically
Tools
9
Setup
• Input Signals
▪ Linear combinations of voltage angles
▪ Voltage angles from 21 substations in BPA
▪ Voltage angles are used to derive frequency deviations using first-order derivative filter
• Modes
▪ North-South A (NS-A)
➢ Typical frequency ~ 0.25 Hz
➢ Alberta vs System
➢ British Columbia and Pacific Northwest swing with Alberta
▪ North-South B (NS-B)
➢ Typical frequency ~ 0.38 Hz
➢ Alberta vs British Columbia and Northern US vs Southern US
10
Methods
• Ringdown
▪ Prony analysis
▪ OBAT also includes VARPRO and Matrix Pencil – results should be validated in future work
▪ Results presented for linear combinations and all substations
▪ Consistent results from two brake insertions provide validation
• Mode Meter
▪ Yule-Walker algorithm for ambient data analysis
➢ Not suitable for use during PDCI probing
➢ Care required to include ringdowns
➢ Estimates are only reported during ambient conditions
▪ Input signals and model orders match BPA setup
▪ Results provide validation for ringdown results
11
May 7 Results
Notes:
• MM = Mode Meter
• Lin Combo = Prony applied to linear combination of signals
• All Sigs = Prony applied to all 21 signals
North-South A North-South B
12
August 21 Results
Notes:
• MM = Mode Meter
• Lin Combo = Prony applied to linear combination of signals
• All Sigs = Prony applied to all 21 signals
North-South A North-South B
Typical OBAT Results: Fit and Shape for NS-A and NS-B
14
Discussion
Observations
• Mode meter estimates generally agree with ringdown analyses
• As expected, modes were well-damped during tests
• North-South A mode not sufficiently excited by brake insertions for reliable ringdown (Prony) analysis
• Good data quality
Recommended Additional Steps
• Ringdown analysis with VARPRO, Matrix Pencil, etc.
• Apply mode meter algorithms that:
▪ Incorporate probing signals to improve estimates
▪ Handle ringdowns in robust implementation
▪ Estimate mode shape
• Evaluate mode shape using non-parametric methods, e.g., Empirical Transfer Function Estimation (ETFE)
• Include PMUs from a wider area
Thank you
15