BLACKOUT AMERICANO E ITALIANO: LUNEDÌ, 10 MAGGIO 2004 ROMA
description
Transcript of BLACKOUT AMERICANO E ITALIANO: LUNEDÌ, 10 MAGGIO 2004 ROMA
August 14th NE Blackout and Common Roots of Blackouts
Damir Novosel, PhDPresident
KEMA Inc., T&D [email protected]
BLACKOUT AMERICANO E ITALIANO:
LUNEDÌ, 10 MAGGIO 2004ROMA
2
System Blackouts: Description and Prevention
1. US Grid
2. Descriptions of the August 14th NE Blackouts
3. Common Roots of Blackouts
4. Conclusions
3
The US at night: the transmission grid
Sparse load:Sparse network
Dense load:Dense network
140 GW 650 GW
60 GW
4
Areas of retail competition
5
Regional reliability coordinators
6
Reliability coordinators & control areas:Complexity
7
Regional Councils and NE Blackout Effects
ASCC
Blackout Area
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 DetroitRegional Councils
8
14 August temperatures
9
10:05:44 Conesville Unit 5 375 MW
1:14:04 Greenwood Unit 1785 MW
1:31:34 Eastlake Unit 5597 MW
3
2
1
Aug. 14th NE Blackout: Initial Generator Outages
10
2,200 MW Power Reversal to Northern Ohio overloading the lines and causing voltage to decline
2:02 Stuart-Atlanta 345kVtrips 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 345kVtrips on overload
4:09 Galion-Ohio 345kVCentral-Muskingum
4:09 East Lima-Fostoria 345kV
August 14th Blackout – Some Key Events4
410
11
9
6
9
6
5
5
11
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 MichiganThe cascading events proceeded including apparent voltage decline.
August 14th Blackout - Some Key Events
17
16
14
15
Cascading Failure Complete at 4:13 PM
13
35
34
33 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
14
NE Blackout - Cascading Failure Complete at 4:13
15
August 14th Blackout - Power Plants Tripped
16
August 14th Blackout Cascade Sequence
17
Common Roots of Blackouts Caused by multiple contingencies
with complex interactions
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
18
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
19
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.)
20
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
21
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
22
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)