1539pk 2003 MAJOR POWER GRID BLACKOUTS IN NORTH AMERICA AND EUROPE Copyright © P. Kundur This material should not be used without the author's consent

1539pk MPB- 1 August 14, 2003 Blackout of Northeast US and Canada

1539pk MPB August 2003 Blackout of Northeast US - Canada Approximately 50 million people in 8 states in the US and 2 Canadian provinces affected  63 GW of load interrupted (11% of total load supplied by Eastern North American Interconnected System) During this disturbance, over 400 transmission lines and 531 generating units at 261 power plants tripped For details refer to: "Final Report of Aug 14, 2003 Blackout in the US and Canada: Causes and Recommendations", US-Canada Power System Outage Task Force, April 5,

1539pk MPB- 3 NERC Regions Affected: MAAC, ECAR, NPCC

1539pk MPB- 4 Conditions Prior to Blackout 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 affected area: Cook 2, Davis Bess plant, East Lake 4, Sammis 3 and Monroe 1 Reactive power supply problems in the regions of Indiana and Ohio prior to noon Operators took actions to boost voltages  voltages within limits System operating in compliance with NERC operating policies prior to 15:05 Eastern Daylight Time Aug 14, 2003 US-Canada Blackout

1539pk MPB- 5 Blackout Started in Midwest

1539pk MPB- 6 Sequence of Events 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 "early warning" assessments as the events were unfolding At the First Energy (FE) Control Center, a number of computer software problems occurred on the Energy Management System (EMS) starting at 14:14  contributed to inadequate situation awareness at FE until 15:45 The first significant event was the outage of East Lake 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 AVR cont'd Aug 14, 2003 US-Canada Blackout

1539pk MPB- 7 East Lake 5 Trip: 1:31:34 pm ONTARIO 2 1

1539pk MPB- 8 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 cascading outages in Ohio and beyond was tripping of Sammis-Star 345 kV line at 16:05:57  Zone 3 relay operation due to low voltage and high power flow Load shedding in northeast Ohio at this stage could have prevented cascading outages that following Sequence of Events cont'd Aug 14, 2003 US-Canada Blackout

1539pk MPB- 9 (3:05:41) (3:32:03) Star- S. Canton (3:41:35)

1539pk MPB- 10 Sammis-Star (4:05:57.5)

1539pk MPB- 11 Tripping of many additional 345 kV lines in Ohio and Michigan 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 from Pennsylvania through New York and Ontario into Michigan  3700 MW of reverse power flow to serve loads in Michigan and Ohio, which were severed from rest of interconnected system except Ontario Voltage collapsed due to extremely heavy loadings on transmission lines Cascading outages of several hundred lines and generators leading to blackout of the region Sequence of Events Aug 14, 2003 US-Canada Blackout

1539pk MPB- 12 Power Transfers Shift at 4:10:38.6 pm

1539pk MPB- 13 Generator Trips to 16:10:38

1539pk MPB- 14 Generator Trips - Next 7 Seconds

1539pk MPB- 15 Northeast Completes Separation from Eastern Interconnection 4:10:43 - 4:10:45 pm

1539pk MPB- 16 Generator Trips - After 16:10:44

1539pk MPB- 17 End of Cascade Areas Affected by the Blackout Service maintained in some area Some Local Load Interrupted

1539pk MPB- 18 Primary Causes of Blackout (as identified by the US-Canada Outage Task Force) 1. Inadequate understanding of the power system requirements:  First Energy (FE) failed to conduct rigorous long-term planning studies and sufficient voltage stability analyses of Ohio control area  FE used operational criteria that did not reflect actual system behaviour and needs  ECAR (East Central Area Reliability Council) did not conduct an independent review or analysis of FE's voltage criteria and operating needs  Some NERC planning standards were sufficiently ambiguous that FE could interpret them in a way that resulted in inadequate reliability for system operation cont'd

1539pk MPB- 19 Causes of Blackout cont'd 2. Inadequate level of situation awareness:  FE failed to ensure security of its system after significant unforeseen contingencies  FE lacked procedures to ensure that its operators were continually aware of the functional state of their critical monitoring tools  FE did not have adequate backup tools for system monitoring 3. Inadequate level of vegetation management (tree trimming)  FE failed to adequately manage tree growth into transmission rights-of-way  resulted in the outage of three 345 kV lines and one 138 kV line cont'd

1539pk MPB- 20 Causes of Blackout cont'd 4. Inadequate level of support from the Reliability Coordinator  due to failure of state estimator, MISO did not become 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

1539pk MPB- 21 September 23, 2003 Blackout of Southern Sweden and Eastern Denmark

1539pk MPB- 22 The Transmission Grid in The Nordic Countries

1539pk MPB- 23 Blackout of 23 September 2003 in Southern Sweden and Eastern Denmark 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 unit in 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 damage caused a double busbar fault at a location 300 km away from the first contingency  resulted in loss of a number of lines in the southwestern grid and two 900 MW nuclear units At 12:37, voltage collapse in the eastern grid section south of Stockholm area  isolated southern Sweden and eastern Denmark system from northern and central grid cont'd

1539pk MPB- 24 The Blackout in Southern Sweden and Eastern Denmark, September 23, 2003 At 12.30: Loss of a 1200 MW Nuclear Unit

1539pk MPB- 25 The Blackout in Southern Sweden and Eastern Denmark, September 23, 2003 At 12.35: Double bus-bar fault leading to -Loss of two 900 MW Nuclear Units -Disrupture of the south-western grid

1539pk MPB- 26 The Blackout in Southern Sweden and Eastern Denmark, September 23, 2003 Voltage Collapse Isolated Subsystem

1539pk MPB- 27 The Blackout in Southern Sweden and Eastern Denmark, September 23, 2003 The blacked-out area after the grid separation at 12.37

1539pk MPB- 28 The isolated system had enough generation to cover only about 30% of its demand  voltage and frequency collapsed within a few seconds, 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 "design contingencies" Blackout of 23 September 2003 in Southern Sweden and Eastern Denmark cont'd

1539pk MPB- 29 September 28, 2003 Blackout of Italy

1539pk MPB- 30 Italian System Blackout of 28 September 2003 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-line between Italy and Switzerland (Mettlen-Lavorgo 380 kV line) at 03:01:22  Sychro-check relay prevented automatic and manual reclosure 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 but was not sufficient to mitigate the overload of a second 380 kV line (Sils-Soazza), which tripped at 03:25:22 due to sag and tree contact cont'd

1539pk MPB- 31  the cascading trend continued and the power deficit in Italy was such that the ties to France, Austria and Slovania were tripped  the outages left the Italian system with a power shortage of 6400 MW  the frequency decay could not be controlled adequately by under-frequency load shedding  over the course of several minutes, the entire Italian 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 Italian System Blackout of 28 September 2003 cont'd