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Recent blackouts in US/Canada and continental Europe:
Is liberalisation to blame?
Janusz W. Bialek
University of Edinburgh, Scotland
The Oregonian, 24 August 2003, after C. Taylor
Recent major blackouts
6 blackouts within 6 weeks affecting 112 million people in 5 countries
14 August 2003, USA/Canada: max ~62 GW lost, ~50M people, restoration up to a few days
28 August 2003, south London, 724 MW lost, 410k people + Tube & Rail at rush hour, restoration: 40 min.
5 September 2003, east Birmingham, 250 MW lost, 220k people, restoration: 11 min.
23 September 2003, Sweden and Denmark, 5M people, restoration 4 hours
28 September 2003, whole Italy except Sardinia, 57M people, restoration: 4 hours.
Who’s next?
What’s important for people and policy makers?
Electricity prices
Environmental effect
Security of supply
Recent blackouts
All blackouts were transmission-based
No problem with generation adequacy
Systems were not stressed prior to blackouts
Two categories:
– Cross-border trades: continental Europe, USA– UK: different, single TSO
What went wrong?
US/Canada
50M people affected, 11% of Eastern Interconnection
Widely covered
Here only short description after US/Canada Power System Outage Task Force “Interim Report: Causes of the August 14th Blackout in the United States and Canada” Nov. 2003.
NE of USA/Canada: before
NE of USA/Canada: after
How it all started: tree flashover
Source: Gerry Cauley, NERC
Effect of a line trip: increased loading on other lines
Effect of a line trip: depressed voltage
Summary for US blackout
Root causes:
– tree growth caused flashovers (FE), – inadequate situational awareness at FE due to
computer failures– inadequate diagnostic support from MISO due to
state estimator failure Interim report identified root causes but failures do
happen
Why a local failure was not contained?
What are the REAL underlying reasons?
Common features with European blackouts
Danish/Swedish blackout: 5 M people
Normal load
1.1 GW nuclear plant trips in south. Sweden
5 min later substation fault trips 1.8 GW nuclear plant and 2 lines in south. Sweden
Total: 2.9 GW + 2 lines lost: system not designed to handle
Local blackout perhaps unavoidable but why a cascade?
Increased power transfers over fewer lines
Voltage dropping in Southern Denmark and Sweden
Additionally power and voltage swings
further lines tripped
Voltage collapse, power stations trip and separation
Blackout
Danish/Swedish blackout: summary
Again problems at the border but insufficient coordination less of the issue
Single mechanical fault in a separator triggered double busbar fault– very rare, need to investigate
Dependence of Eastern Denmark on supplies from Sweden
Most “technical” of the blackouts
Italy
3 am: import 6.6 GW 24% of total demand, 300 MW over agreed level
Fully-loaded CH line touches tree and trips
Unsuccessful reclosing due to angle stability
3.11 am: ETRANS informs GRTN (disputed)
GRTN reduces imports by 300 MW (not enough)
3.25 another CH overloaded line sags and trips on tree flashover
Italy loses synchronism with UCTE
Dynamic interactions cause fast voltage collapse in Italy
Tie-lines trip almost instantaneously
Island operation: 6.4 GW generation deficit leads to frequency collapse
10 GW of load shed automatically but 21 out of 50 thermal plants trip by under-voltage relays
Blackout 2.5 minute after separation: whole Italy, except of Sardinia.
Italy: summary
Largest blackout in Europe since WW2
Over-dependence on imports:
– 1987 referendum blocked nuclear power– Not enough power stations built
Relatively weak and congested tie-lines
Weak coordination between ETRANS and GRTN
– ETRANS did not assess the urgency as the consequences of first outage were in Italy
– GRTN could not assess the situation as the first outage was in CH
Angle instability and voltage collapse prevented successful island operation of Italy
Common features of US/Canada and European blackouts
Happened at the boundaries between control areas (countries)
Import areas dependent on transmission from export area
Were allowed to spread due to the insufficient coordinated response (to a lesser extent in Scandinavia)
What are the common underlying reasons?
Interconnection brings significant benefits but may be also a threat
North America
3 interconnections (Eastern, Western, Texas)
10 regional reliability councils and over 130 control areas!
balkanisation
Balkanisation
Europe's synchronous areasEurope's synchronous areas
DC connection
Source: P. Bonnard, 2003 IEEE Trans. Distr. Conf
Common patterns in US and Europe
Historically: self-sufficient utilities serving native load
Interconnections:
– sharing generation reserves– help each other to deal with disturbances – Also limited coordinated exchanges– Maintaining conservative security margins
Liberalisation:
– Uncoordinated cross-border trades (8% of generation in Europe, 4 times increase since 1998 in US)
– Transmission systems run closer to the limits
Parallel flows: northern France – Italy trade
Source: H-J Haubrich, W. Fritz
Unexpected flows in bottlenecks
Flows through the Belgian Grid on July 14, 1999
0
1000
2000
3000
4000
1 3 5 7 9 11 13 15 17 19 21 23
Hour
Pow
er (M
W)
Unidentified flows
Expected flows
Source: P. Bonnard, 2003 IEEE Trans. Distr. Conf
Main generic reason for recent cascading blackouts
It is not liberalisation to blame but the way utilities operate
Operational procedures developed in the world of monopolistic, vertically integrated utilities cannot deal effectively with liberalisation, open access and cross-border trades
Phone-based communication
None sees the big picture
Limited exchange of real-time data
No automatic coordinated response to emergencies
The future
Is Mega-TSO a solution?
– would probably create more problems than solve– politically unacceptable
New technical, organisational and political solutions needed for coordinated but decentralised operation
Alternative: more blackouts or restrain cross-border trades
Need to limit exchange of commercially sensitive information
Trade off between protecting local area and the whole interconnection
Fallacy: transmission investment will prevent blackouts
Bill Richardson, former US Energy Secretary: “we are superpower with third world grid”.
Underinvested grid suffers from bottlenecks but it may still be operated safely
Converse true
Increase in transmission capacity will be sooner or later used up
back to square one although at higher level
Source: D. Kirschen, G. Strbac: “Why investments do not prevent blackouts” UMIST, 2003
Fallacy cntd.
Transmission investment enables competition and reduces prices
but does not necessarily improve security in the long term
Operational rules are the key
They need to be adapted to the new situation
UK
UK blackouts
Birmingham and London: local blackouts
Remarkably similar to each other but different from US/European ones
NGC single grid operator in E&W, soon GB
In both cases recently commissioned protection equipment tripped due to wrong settings
Questions asked about commissioning procedures, use of outside contractors, maintenance scheduling, excessive downsizing
Findings not published
Conclusions
The blackouts were disasters waiting to happen
Underlying common reason: utilities need to adapt to liberalisation, open-access and cross-border trades
New framework of decentralised yet coordinated operation needed
It is not over yet!
Recent blackouts in US/Canada and continental Europe:
Is liberalisation to blame?
Janusz W. Bialek
University of Edinburgh, Scotland