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# The Mathematics of the Great U.S. Blackout August 14, 2003 - PowerPoint PPT Presentation

The Mathematics of the Great U.S. Blackout August 14, 2003. Ralph Fehr, P.E. Engineering Consultant. The Mathematics of the Great U.S. Blackout August 14, 2003.

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Presentation Transcript

August 14, 2003

Ralph Fehr, P.E.

Engineering Consultant

August 14, 2003

Note: The photograph on the preceding slide has been circulating on the Internet since shortly after August 14, 2003. It is impressive, dramatic, and FAKE. But it does attempt to indicate the huge impact and expanse of the August 14 event, and most importantly, it makes for a cool title slide!

Ralph Fehr, P.E.

Engineering Consultant

NERC is a not-for-profit company formed after the 1965 Northeast Blackout to promote the reliability of the bulk electrical system that serves North America.

NERC is divided into 10 regional reliability councils.

Each council monitors utilities within its geographic area.

The August 14, 2003 Blackout was caused by a cascading series of events.

What started the ball rolling?

A wire attached at two points sags series of events.under its own weight.

The amount of series of events.sag is a function of tension.

Tension is a function of wire temperature and weight.

Temperature is a function of several variables – but a major contributor is electrical loading.

As the wire temperature INCREASES, the tension DECREASES.

For a level span, the maximum sag D is the y-coordinate at the

midpoint of the line, and is given by:

where S = span length

TH = horizontal component of tension

w = conductor weight per unit length

y series of events.

y = cosh(x)

x

Mathematical Analysis of Root Cause

Alternate Mathematical Analysis of Root Cause

Cost maintenance > 0

Outage Sequence of Events series of events.Transmission Map Key

ONTARIO series of events.

ONTARIO

East Lake 5 Trip: 1:31:34 PM

2

1

Stuart Atlanta Trip: 2:02 PM series of events.

MISO State Estimator and series of events.Reliability Analysis

• MISO state estimator and contingency analysis ineffective from 12:37 to 16:04

• State estimator not solving due to missing information on lines out in Cinergy then DPL

• Human error in not resetting SE automatic trigger

• Using Flowgate Monitoring tool to monitor conditions on previously identified critical flowgates

FirstEnergy Computer Failures series of events.

• 14:14 Alarm logger fails and operators are not aware

• No further alarms to FE operators

• 14:20 Several remote consoles fail

• 14:41 EMS server hosting alarm processor and other functions fails to backup

• 14:54 Backup server fails

• EMS continues to function but with very degraded performance (59 second refresh)

• FE system data passed normally to others: MISO and AEP

• AGC function degraded and strip charts flat-lined

• 15:08 IT warm reboot of EMS appears to work but alarm process not tested and still in failed condition

• No contingency analysis of events during the day including loss of East Lake 5 and subsequent line trips

Phone Calls to FirstEnergy series of events.

• FE received calls from MISO, AEP, and PJM indicating problems on the FE system but did not recognize evolving emergency

• 14:32 AEP calls regarding trip and reclose of Star-S. Canton

• 15:19 AEP calls again confirming Star-S. Canton trip and reclose

• 15:36 MISO calls FE regarding contingency overload on Star-Juniper for loss of Hanna-Juniper

• 15:45 FE tree trimming crew calls in regarding Hanna-Juniper flashover to a tree

• PJM called MISO at 15:48 and FE at 15:56 regarding overloads on FE system

The Chamberlin - Harding 345 kV line series of events. sags into a tree at 3:05:41.

Contact with tree causes a ground fault which results in very high current.

The protective relays on the Chamberlin – Harding line sense the high current and trip (de-energize) the line.

A Digital Fault Recorder (DFR) at nearby Juniper Substation recorded the fault current.

Chamberlin-Harding (3:05:41) series of events.

Chamberlin-Harding Indication of Ground Fault Due to Tree Contact as Measured by DFR at Juniper

y = ex sin x

NOT STABLE

should be

y = e-x sin x

Hanna-Juniper Contact as Measured by DFR at Juniper

(3:32:03)

(3:05:41)

Hanna Juniper Confirmed as Tree Contact at Contact as Measured by DFR at JuniperLess than Emergency Ratings of Line

(3:05:41) Contact as Measured by DFR at Juniper

(3:32:03)

Star- S. Canton (3:41:35)

ONTARIO Contact as Measured by DFR at Juniper

Situation after Initial Trips 3:05:41 – 3:41:35

Canton Central – Tidd Contact as Measured by DFR at Juniper

(3:45:41)

20% Contact as Measured by DFR at Juniper

20%

20%

20%

20%

Source

0% Contact as Measured by DFR at Juniper

25%

25%

25%

25%

Source

0% Contact as Measured by DFR at Juniper

0%

33%

33%

33%

Source

0% Contact as Measured by DFR at Juniper

0%

0%

50%

50%

Source

0% Contact as Measured by DFR at Juniper

0%

0%

0%

100%

Source

138 kV Lines Overload and Cascade Near Akron Contact as Measured by DFR at Juniper

138 kV Cascade Contributes Further Contact as Measured by DFR at Juniperto Overload of Sammis-Star

15:51:41 EDT

15:05:41 EDT

16:05:55 EDT

15:32:03 EDT

15:41:35 EDT

Sammis-Star Contact as Measured by DFR at Juniper

(4:05:57.5)

Sammis-Star Zone 3 Relay Operates Contact as Measured by DFR at Juniperon Steady State Overload

Operating point

must lie below blue

curve, or line will

trip.

increases, operating

point moves up and

to the left.

Actual Loading on Critical Lines Contact as Measured by DFR at Juniper

Actual Voltages Leading to Sammis-Star Contact as Measured by DFR at Juniper

Remaining Contact as Measured by DFR at Juniper

Paths

Major Path to Cleveland Blocked after Loss of Sammis-Star 4:05:57.5 PM

ONTARIO Contact as Measured by DFR at Juniper

345 kV Lines Trip Across Ohio to West

ONTARIO Contact as Measured by DFR at Juniper

Generation Trips 4:09:08 – 4:10:27 PM

Power Transfers Shift at 4:10:38.6 PM after 4:10:37.5 – 4:10:38.6 PM

Eastern Eastern Michigan (Detroit) Unstable after 4:10:37.5 – 4:10:38.6 PMVoltage and Frequency Collapse and Pole Slipping

Ontario – Michigan Interface Flow and Voltages Beginning 16:10:38

Generator Trips to 16:10:38 after 4:10:37.5 – 4:10:38.6 PM

Generator Trips – Next 7 Seconds after 4:10:37.5 – 4:10:38.6 PM

Overloads on PJM – NY Ties 4:10:39 PM after 4:10:37.5 – 4:10:38.6 PM

PJM – NY Separating 4:10:44 PM after 4:10:37.5 – 4:10:38.6 PM

Cleveland – Toledo Island 4:10:39 - 4:10:46 PM after 4:10:37.5 – 4:10:38.6 PMCleveland Blacks Out

Conditions at Niagara Indicate Progressively Worsening Stability Conditions with Prior Events

Island Breaks Up: 4:10:46 – 4:13 PM Stability Conditions with Prior Events

Frequency in Ontario and New York during Breakup Stability Conditions with Prior EventsNiagara Generation Stays with Western NY

Generator Trips – After 16:10:44 Stability Conditions with Prior Events

Some Local Load Interrupted Stability Conditions with Prior Events

Areas Affected by the Blackout

Service maintained

in some area

Lessons Learned Stability Conditions with Prior Events

Better maintenance practices

Better training for system operators

Better communications between utilities

Can it happen again? Stability Conditions with Prior Events

What do you think?

Thank you! Stability Conditions with Prior Events

Manhattan skyline with only emergency lighting – August 14, 2003