BLACKOUT AMERICANO E ITALIANO: LUNEDÌ, 10 MAGGIO 2004 ROMA

1. BLACKOUT AMERICANO E ITALIANO: LUNEDÌ, 10 MAGGIO 2004 ROMA August 14th NE Blackout and Common Roots of BlackoutsDamir Novosel, PhDPresidentKEMA Inc., T&D Consultingdnovosel@kema.com

2. System Blackouts: Description and Prevention • US Grid • Descriptions of the August 14th NE Blackouts • Common Roots of Blackouts • Conclusions

3. Sparse load: Sparse network Dense load: Dense network 650 GW 140 GW The US at night: the transmission grid 60 GW

4. Areas of retail competition

5. Regional reliability coordinators

6. Reliability coordinators & control areas:Complexity

7. ASCC Blackout Area Regional Councils and NE Blackout Effects • August 14, NE USA (8 states) and Canada (2 provinces) affected: • 50 million people • 34,000 miles of transmission • ~290 Generating units • ~61,800 MW • Restoration efforts • A day to restore power to NY City • Two days to restore power to Detroit Regional Councils

8. 14 August temperatures

9. 10:05:44 Conesville Unit 5 375 MW 1:14:04 Greenwood Unit 1 785 MW 1:31:34 Eastlake Unit 5 597 MW Aug. 14th NE Blackout: Initial Generator Outages 1 2 3

10. 2,200 MW Power Reversal to Northern Ohio overloading the lines and causing voltage to decline August 14th Blackout – Some Key Events 2:02 Stuart-Atlanta 345kV trips due to a fault 3:05 Harding-Chamberlain 345 kV sags into a tree 3:32 Hanna-Juniper 345kV sags into a tree, other 345 kV lines disconnect => 16 of 135kV lines overload and trip 4:06 Sammis-Star 345kV trips on overload 4:09 Galion-Ohio 345kV Central-Muskingum 4:09 East Lima-Fostoria 345kV 4 5 6 6 5 9 9 10 4 11

11. Cascading Failure Complete at 4:13 PM August 14th Blackout - Some Key Events 14 20 Generators around Lake Erie (app. 2,174 MW) tripped Michigan lines trip 1256 MW Generator trips Transmission system separation Another power reversal, power flow (2,800 MW) to Northern Ohio through Ontario and Michigan The cascading events proceeded including apparent voltage decline. 15 16 17

12. 4:10:50 Ontario system separates from New York 4:10:43 Long Mountain – Plum Tree (345 kV Line) 4:10:45 Remaining lines between Ontario and Eastern Michigan separate August 14th Blackout - Some Key Events 33 34 35

13. NE Blackout - Cascading Failure Complete at 4:13

14. August 14th Blackout - Power Plants Tripped

15. August 14th Blackout Cascade Sequence

16. Usually no “single” cause • Sequence of low probability events difficult to accurately predict • Practically infinite number of operating contingencies, different from the expectations of system designers • Operators cannot act fast enough for fast developing disturbances Common Roots of Blackouts • Caused by multiple contingencies with complex interactions

17. Pre-conditions and Factors for Blackouts • Congested grid • No lines & generators in my backyard! • Not enough reactive support • Tight operating margins, with less redundancy • Regulatory uncertainty • Low level of investment in recent years • How and who to invest? • How to recover costs? The bulk power system was not designed to transfer large amounts of power, but to improve network security

18. Pre-conditions and Factors for Blackouts • Inadequate right-of-way maintenance • FE failed to adequately trim trees • Aging equipment, prone to failures • Insufficiently coordinated equipment maintenance and generation scheduling • Weather (high temperatures; wind, thunderstorm, fog, etc.)

19. How Do Disturbances Turn Into a Blackout? Cascading events that cause disturbances to propagate • Sequential tripping due to overloads, power swings, and voltage fluctuations • Protection involved in ~70% of blackout events in North America • In some cases, protection miss-operation or unnecessary actions: incorrect settings, uncovered application design flows, or HW failures • Inadequate or faulty EMS/SCADA system (alarm burst) • E.g. FE lost its system condition alarm system around 2:14 pm • MISO (FE’s reliability coordinator) had an unrelated software problem and was unable to tell that FE’s lines were becoming overloaded • Insufficient reactive support where and when required • Inability of operators to prevent further propagation • Sacrifice own load or cut interties or get support from neighbors

20. Contributing Factors that Allow Blackout to Spread • Lack of coordinated response during developing disturbances • PJM saw the growing problem, but did not have joint procedures in place with MISO to deal with the problem quickly and effectively • Should we help or should we separate? • Inadequate planning/operation studies • FE didn’t ensure the security of its transmission system because it didn’t use an effective contingency analysis tool routinely • Lack of inadequate Special Protection Schemes to prevent spreading of the disturbance: • Prevent further overloading of the lines • Arrest voltage decline • Initiate pre-planned separation of the power system for severe emergencies

21. Conclusions • North-American Grid not designed for large transfers • Increase in the number and frequency of major blackouts • Analysis of recent disturbances reveals some common threads among them, leading to conclusions that: • Propagation can be arrested • Impact of disturbances/outages can be reduced • Various cures to reduce the possibility of future outages • A need for deployment of well-defined and coordinated overall plans (planning, operations and maintenance)