Major Power Grid Blackouts in North America and Europe

8/12/2019 Major Power Grid Blackouts in North America and Europe

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Copyright P. Kundur

This material should not be used without the author's consent


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! Approximately 50 million peoplein 8 states in theUS and 2 Canadian provinces affected

" 63 GW of load interrupted (11% of total loadsupplied by Eastern North AmericanInterconnected System)

! During this disturbance, over 400 transmission linesand 531 generatingunits at 261 power plants tripped

! For details refer to: "Final Report of Aug 14, 2003Blackout in the US and Canada: Causes and

Recommendations", US-Canada Power System

Outage Task Force, April 5, 2004. www.NERC.com


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! Electricity demand high but not unusually high! Power transfer levels high, but within established

limits and previous operating conditions

! Planned outages of generating units in the affectedarea: Cook 2, Davis Bess plant, East Lake 4, Sammis

3 and Monroe 1

! Reactive power supply problems in the regions ofIndiana and Ohio prior to noon

! Operators took actions to boost voltages" voltages within limits

! System operating in compliance with NERCoperating policies prior to 15:05 Eastern Daylight

Time

Aug 14, 2003 US-Canada Blackout


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! The Midwest ISO (MISO) state estimator and real-time contingency analysis (RTCA) software not

functioning properly from 12:15 to 16:04

" prevented MISO from performing proper "earlywarning" assessments as the events wereunfolding

! At the First Energy (FE) Control Center, a number ofcomputer software problems occurred on the

Energy Management System (EMS) starting at 14:14

" contributed to inadequate situation awarenessat FE until 15:45

! The first significant event was the outage of EastLake generating unit #5 in the FE system at 13:31:34

" producing high reactive power output" voltage regulator tripped to manual on

overexcitation

" unit tripped when operator tried to restore AVRcont'd



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ONTARIO

2

1

ONTARIO


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! Initial line trips in Ohio, all due to tree contact:" Chamberlin-Harding 345 kV line at 15:05:41" Hanna-Juniper 345 kV line at 15:32:03" Star-South Canton 345 kV line at 15:41:35

! Due to EMS failures at FE and MISO control centers,no proper actions (such as load shedding) taken

! Critical event leading to widespread cascadingoutages in Ohio and beyond was tripping of

Sammis-Star 345 kV line at 16:05:57

" Zone 3 relay operation due to low voltage andhigh power flow! Load shedding in northeast Ohio at this stage could

have prevented cascading outages that following



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(3:05:41)(3:32:03)

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


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Sammis-Star(4:05:57.5)


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! Tripping of many additional 345 kV lines in Ohio andMichigan by Zone 3 (or Zone 2 set similar to Zone 3)

relays

! Tripping of several generators in Ohio and Michigan! At 16:10:38, due to cascading loss of major lines in

Ohio and Michigan, power transfer from Canada

(Ontario) to the US on the Michigan border shifted

" power started flowing counter clockwise fromPennsylvania through New York and Ontario

into Michigan

" 3700 MW of reverse power flow to serve loadsin Michigan and Ohio, which were severedfrom rest of interconnected system except

Ontario

! Voltage collapsed due to extremely heavy loadingson transmission lines

! Cascading outages of several hundred lines andgenerators leading to blackout of the region



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Areas Affected by the Blackout

Service maintained

in some area

Some Local Load

Interrupted


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1. Inadequate understanding of the power systemrequirements:

# First Energy (FE) failed to conduct rigorouslong-term planning studies and sufficient

voltage stability analyses of Ohio control area

# FE used operational criteria that did not reflectactual system behaviour and needs

# ECAR (East Central Area Reliability Council)did not conduct an independent review or

analysis of FE's voltage criteria and operatingneeds

# Some NERC planning standards weresufficiently ambiguous that FE could interpret

them in a way that resulted in inadequate

reliability for system operation

cont'd


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2. Inadequate level of situation awareness:

# FE failed to ensure security of its system aftersignificant unforeseen contingencies

#FE lacked procedures to ensure that itsoperators were continually aware of the

functional state of their critical monitoring

tools

# FE did not have adequate backup tools forsystem monitoring

3. Inadequate level of vegetation management (treetrimming)

# FE failed to adequately manage tree growthinto transmission rights-of-way

$ resulted in the outage of three 345 kVlines and one 138 kV line

cont'd


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4. Inadequate level of support from the ReliabilityCoordinator

# due to failure of state estimator, MISO did notbecome aware of FE's system problems early

enough

$ did not provide assistance to FE# MISO and PJM (Regional Transmission

operator) did not have in place an adequate

level of procedures and guidelines for dealing

with security limit violations due to a

contingency near their common boundary


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! Pre-disturbance conditions:" system moderately loaded" facilities out of services for maintenance:

$400 kV lines in South Sweden$4 nuclear units in South Sweden$3 HVDC links to Germany and Poland

! The first contingency was loss of a 1200 MW nuclear unitin South Sweden at 12:30 due to problems with steam

valves

" increase of power transfer from the north" system security still acceptable

! Five minutes later (at 12:35) a disconnector damagecaused a double busbar fault at a location 300 km away

from the first contingency

" resulted in loss of a number of lines in thesouthwestern grid and two 900 MW nuclear units

! At 12:37, voltage collapse in the eastern grid sectionsouth of Stockholm area

" isolated southern Sweden and eastern Denmarksystem from northern and central grid

cont'd


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At 12.30: Loss of a 1200 MWNuclear Unit


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At 12.35: Double bus-bar fault leading to-Loss of two 900 MW Nuclear Units-Disrupture of the south-western grid


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Voltage Collapse

IsolatedSubsystem


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The blacked-out area after the grid separation at 12.37


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! The isolated system had enough generation to coveronly about 30% of its demand

" voltage and frequency collapsed within a fewseconds, blacking out the area

! Impact of the blackout:" loss of 4700 MW load in south Sweden

$1.6 million people affected$City of Malmo and regional airports and rail

transportation without power

" loss of 1850 MW in eastern Denmark$2.4 million people affected$City of Copenhagen, airport and rail

transportation without power

! Result of an (n-3) contingency, well beyond "designcontingencies"


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! Predisturbance conditions (Sunday, 3:00 am):" total load in Italy was 27,700 MW, with 3638 MW

pump load

" total import from rest of Europe was 6651 MW! Sequence of events:

" a tree flashover caused tripping of a major tie-linebetween Italy and Switzerland (Mettlen-Lavorgo

380 kV line) at 03:01:22

" Sychro-check relay prevented automatic and manualreclosure of line due to the large angle (42) across

the breaker" resulted in an overload on a parallel path" attempts to reduce the overload by Swiss

transmission operators by network change was not

successful

" at 03:21 import by Italy was reduced by 300 MW butwas not sufficient to mitigate the overload of a

second 380 kV line (Sils-Soazza), which tripped at03:25:22 due to sag and tree contact

cont'd


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" the cascading trend continued and the powerdeficit in Italy was such that the ties to France,

Austria and Slovania were tripped

" the outages left the Italian system with a powershortage of 6400 MW

" the frequency decay could not be controlledadequately by under-frequency load shedding

" over the course of several minutes, the entireItalian System collapsed at 3:28:00

! The blackout affected about 60 million people" total energy not delivered 180 GWh" worst blackout in the history of Italy" power was restored after 3 hours in the

northern area and during the same day for

most of Italy

Major Power Grid Blackouts in North America and Europe

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