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6Nov98

Power System Dynamics Analysis

Complexity in the WSCC

August 10, 1996 System Disturbance

David P. Chassin, October 16, 2002

Contact: david.chassin@pnl.gov

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August 1996 West Coast BlackoutSummary of Events

WSCC 8-10-96 15:48 PAST major disturbance

4 islands, 7.5M customers out up to 9 hours

Initiating event: 500 kV Keeler-Allston flashover to trees

Trip cause: poor right-of-way maintenance Numerous supporting events

Follow-up events

COI limit lowered to 3200 MW (Aug 11)

Account for limits at McNary (exciter) and The Dalles (fish) Raised Aug 12-14 to 3600 MW to avoid blackouts in CA

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PNNL and Power Systems

DOE Transmission Reliability Program Real-Time Grid Reliability Management

Reliability and Markets, Load as a Resource

Distributed Energy Resources Integration

Infrastructure Assurance Outreach Program Utility vulnerability assessments

Interaction with NERC, others on security topics

Interest in SCADA security

Energy System Transformation Initiative Integrated econophysics modeling and simulation

Next generation power technology development

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Wide-Area Measurement SystemDynamic monitor network supports advanced

analysis

Better information supports better

- and faster - decisions.

System planning

Observedresponse

Power

System

Unobservedresponse

Information

Automatic control

System operation

Disturbances

DecisionProcesses

Measurement

Based

Information

System

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Real-Time System DataCollected from various monitors throughout the grid

Bonneville Power Administration Phasor Data Concentrator

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Power System Measurement ToolsTools for managing data & signal analysis

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Ringdown Analysis ToolAdvanced dynamic analysis

model fitting w indow

Time in Seconds

165 170 175 180

Malin MW

Unfiltered signals

Brake insertion #2, 09/04/97(Alberta strong ly connected)

Reference time 09-04-97 23H42m35s

PACI Mode: 0.294 Hz @ 5.3% dampingAlberta : 0.418 Hz @ 5.1% damping

900

1000

1100

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Data collected on Dittmer P PSMsample rate = 60/second

Extracting a linear modelfrom measured data

Dynamic analysis

Model validation

Control design

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Advanced Dynamic SystemAnalysis and Model Validation

4000

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Time in Seconds

Simulated COI Power (initial WSCC base case)

Observed COI Power (Dittmer Control Center)

August 10, 1996 post-disturbance analysis

Determine if model

calibration is needed.

Currently working with western utilities to improve power grid models

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Abstract

Transactive

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Power System Econophysics

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Controlprocess

State m

Thermodynamicprocess

State x

Qwaste

Qin

QoutCin

Cout

Cprofit

control

data

85.026.12

2

3

2

85.02

6.14

Q

eQ

QPPJM 1999 Load/Price Probability Distributions

Q= Qmax (11/P2)4.54

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Overview of WSCC August 10, 1996

15:48 PAST Disturbance

Based on WSCC Disturbance Report

Approved by WSCC OperationsCommittee on October 18, 1996

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High northwest transmission loading

High imports to CA

Heavy imports from Canadaand Idaho

COI at 4750 MW

Similar to conditions prior to7/2/96 disturbance

Warning signs visible

Previous high-load issues

Small power/large voltageswings

Suggested voltage supportproblems in NW

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Equipment out of service

Lines 500 kV: Big Eddy-Ostrander,

John Day-Marion, and Marion-Lane (reactive support aroundPortland) flashover to trees

115 kV: Allston-Rainer degraded

hdwr, Longview-Lexington cableinstallation.

Breakers 500 kV: Marion, Keeler

(modifications)

Transformers

500/230 kV: Keeler (modification)Static VAR Comp (SVC) Keeler reduced support to

500 kV(tied to 230 kV side)

xxx

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Triggering Events

15:42:37 Keller-Allston Sags into trees, flashes, trips Overload par-lines hold 5 min McNary react-power at max

15:47:29 St. Johns-Merwin Lines trip on relay malfunc.

KA par-line loads increase15:47:36 Ross-Lexington Tree flashover and trip 207 MW from Swift lost System voltage sags

15:47:36 McNary Units trip, exciter problem

System power/voltage osc. beginsID-UT-CO-AZ-NM-NV Surge COI power flows down east side Out-of-step trips CA-AZ remain tied together

! ! !

!

!

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Final Result

28,000 MW of under-frequency load shedding20,000 MW of undesired generation lossFour major islands Northern California (North of LA to Oregon border)

Losses: 11,600 MW load; 7,900 MW generation Frequency excursions: 58.5460.758.3, restored in 2.5 hrs.

Southern California (SoCal, NV, AZ, NM, El Paso, Baja) Losses: 15 820 MW load; 13,500 MW generation Frequency excursions: 61.358.5, restored in 70 min.

Northern (BC, OR, WA, MT, WY, ID) Losses: 2,100 MW load; 5,700 MW generation Frequency excursions: 60.4, restored in 7 minutes

Alberta Losses: 970 MW load; 146 MW generation Frequency excursions: 60.459.0, restored in 6 minutes

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Open Questions re. Complexity

Report only identifies the incontrovertible pointsand fails to address more controversial questions: Why was line maintenance inadequate?

Why was system operated in single-contingency mode?

Why did AZ-CA separation scheme fail to operate? Why did models fail to predict oscillations?

Why did system damping fail?

Lesson for us: Dont go just by the official reports. Much more is not

reported or discussed because of sensitivities. Thesocial dynamics of a tightly knit community factors intowhat is knowable. We have to look deeper.

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Problems PersistWECC Oct 8 2002 15:31 PDT

59.550

59.600

59.650

59.700

59.750

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59.900

59.950

60.000

60.050

22:3

0:4

3.2

0GMT

22:3

0:5

1.8

4GMT

22:3

1:0

0.4

8GMT

22:3

1:0

9.1

2GMT

22:3

1:1

7.7

6GMT

22:3

1:2

6.4

0GMT

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1:3

5.0

4GMT

22:3

1:4

3.6

8GMT

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1:5

2.3

2GMT

22:3

2:0

0.9

6GMT

22:3

2:0

9.6

0GMT

Time

Freq

2900 MW generation tripped

1400 MW Chief Joe brake inserted

~86 MW UFLS

~350 MW load loss

480 MW generation dropped

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Questions and Comments