Blackouts. 29/10/2014 Dirk Van Hertem & Steven De Boeck

Transcription

1 Blackouts 29/10/2014 Dirk Van Hertem & Steven De Boeck

2 Quiz When was the last blackout in Belgium? First one to present his IEEE card with the correct answer receives a gift

3 The answer: August 4, 1982

4 Security of supply and reliable energy provision Electric power systems are complex Large (physically) Widely dispersed (geographically) International context (Quasi) non-storable energy Unpredicted behavior can have consequences throughout the system Power systems are historically grown Prime objective: reliable and economic supply Redundancy has been built-in to ensure adequate and acceptable continuity of supply Main question: How much redundancy, and at what cost Balance between over-investing and under-investing

5 Defining reliability In general, reliability (systemic def.) is the ability of a person or system to perform and maintain its functions in routine circumstances, as well as hostile or unexpected circumstances. (Wikipedia) Adequacy: in power systems is referred to as the existence of sufficient facilities within the system to satisfy the demand. These facilities include those necessary to generate sufficient energy and the associated transmission and distribution networks required to transport the energy to the actual consumer load points capacity Adequacy of generation: Long term adequacy is normally no problem Short term adequacy: balancing generation and load Adequacy of transmission and distribution system: network adequacy Solved with N-1 criterion or equivalent Security: relates to the ability of the system to withstand sudden changes (disturbances) arising within that system

6 The electrical power system is designed in a robust manner to withstand all normal fluctuations, uncertainties and contingencies

7 Types of large disturbances leading to outages

8 Types of disturbances Local interruptions Usually caused by a small local problem (short circuit or device failure) Usually results in disconnection of residential customers Limited restoration time needed for most users (open ring structure) Where and when Affected customers Duration Rotterdam (2002) 300,000 Up to several hours London (2003) 500,000 1 hour Copenhagen (2003) 4,000,000 Up to 2 hours Rolling blackout Planned interruptions of power delivery Happens in markets with constrained generation and/or transmission network. ==> Shortfall of capacity Customers often do not know when they will be disconnected Where and when Affected customers Duration California blocks Couple of weeks Italy ,000,000 Couple of days New Zealand , days

9 Types of electrical interruptions Brownout Reduction of electrical power: over-usage, shortage Intentional or unintentional drop in voltage Intentional ==> to reduce load during emergencies Load shedding is usually sufficient to mitigating the problem Blackout Complete shut down of the power system (or a part of it) Including the backbone Unintentional Very high economical impact Step by step restoration process that take several hour up to several days

10 The Triggering Event / Root Cause of the Blackout

11 Common factors of a triggering event Failure of Equipment (US Canada 2003) Malfunctioning of protective device ( San Diego 2011) Extreme weather, Lighting (Gudrun Sweden 2005) Bad vegetation management (US Canada 2003) Human Error (Italy 2003 / Germany 2006 / India 2012 / San Diego 2011) Lack of situational awareness between different TSO s (US Canada 2003 / Italy 2003 / Germany 2006 / India 2012) Operational and maintenance planning error (India 2012) Bad communication between TSOs (Germany 2006 / India 2012) Control system error (US Canada 2003)

12 Consequences Impact type: Material damage Direct and indirect Cost of the outage Load/Generation Human Safety Health Society Economic Time of day: Weekend Working hours Duration: Short / long unavailability Anticipated or not duration

13 Recent Blackouts: US-Canada blackout 14 August 2003

14 US-Canada Blackout 14 august 2003 Initiating event: Tripping of a generator (East Lake 5 ==> essential for voltage stability) and a transmission line (Harding-Chamberlain) Human error: switching off automatic State Estimator (normally every 5 min) and Real Time Contingency Analysis Sequence of events: Software malfunctioning ==> No early warning ==> No contingency analysis possible Overloads: Extra lines trip due to contact with the trees Wrong counter measurements Cascading of transmission lines More generator units trip ==> blackout of a large area Load shedding in an early stage could have reduced the impact

15 US-Canada Blackout 14 august 2003 Before After

16 US-Canada Blackout 14 august million people without electricity 63 GW load interrupted 400 transmission lines tripped 531 generation units tripped

17 Recent Blackouts: Blackout Italy 28 September 2003

18 Italy 28 September 2003 Initial situation (3:00 am) Total load : Total import to Italy : MW (3638 MW load from pumped storage) 6651 MW (only 6000MW scheduled) Initiating event: Flash over to a tree ==> important tie line CH IT trips (Mettlen Lavorgo 380 kv) Synchro check relay prevents a reconnection of the line, because of a to large angle (42 ) Sequence of events: Overloading of parallel lines: only 15 min to remove the overload Swiss TSO tries to relieve these lines, attempts fail (to big angle) Italy reduces import ( - 300MW), but to little to late Second line trips, followed by others ==> Cascading (<15min)

19 Italy 28 September 2003

20 Italy 28 September 2003 Consequences: Production shortage of 6400MW at system collapse 60 million people affected 180 GWh not supplied North reconnected after 3h Last customer reconnected after 18h

21 Recent Blackouts: Gudrun Storm Sweden 8 January 2005

22 Gudrun storm Sweden 8 January 2005 Initiating event: A storm causes many lines to fall over ==> Multiple independent contingencies (N-k) Not only electricity system affected 17 people died 75 million m³ of trees fell over ==> impacted wood prices Impact for roads, rail traffic, communication services,

23 Gudrun storm Sweden 8 January 2005 Consequences: km transmission lines damaged 4 nuclear generator units shut down Total cost of 274 million EUR Restoration process: Number of people Restoration time Within 24h to 3 days to 7 days to 20 days More than 20 days

24 Recent Blackouts: Continental Europe 4 November 2006 ==> not a real blackout!

25 Continental Europe: 4 November 2006 Initial situation A boat needs to pass underneath a transmission line EON Netz and other RWE TSO make the grid calculations Meyerwerft asks EON to let the boat pass 1h earlier, EON agrees but does not warn the other TSO s (boat pass initially at 5th Nov 01:00 --> advanced to 4th November 22:00) RWE TSO and TenneT are informed at 19:00 Initiating event: Disconnecting of line (1h earlier than planned) (at that moment the system was not N-1 secure) Sequence of events: A parallel line (Wehrendorf Landesbergen) becomes heavily loaded This lines trips after 32 minutes Immediate tripping of several other lines (cascading-effect) The European grid splits in three parts, with frequency deviating from 50Hz

26 Continental Europe: 4 November 2006 Conneforde Diele substation Borken busbars decoupled Cascade effect 18 seconds 22:10:13-22:10:31

27 Continental Europe: 4 November 2006 During one of the phone calls between RWE TSO and EON Netz (between 21:46 21:52) It becomes clear that protection settings are different on each side of the transmission line

28 Continental Europe: 4 November 2006 Consequences West Europe: 15 million households affected (16.7 GW) The defence plan needed to operate to avoid full system collapse

29 Continental Europe: 4 November 2006 Consequences West Europe: MW generation shed 75% of wind generation tripped

30 Recent Blackouts: San Diego Blackout on September 8th 2011 at 15:27

31 San Diego Blackout 8 September 2011

32 San Diego Blackout 8 September 2011 ==> Total lost load: 7890MW ==> Total customers affected: +2,7million

33 Recent Blackouts: Indian Black-outs 30 and 31 of July 2012

34 Indian Black-outs 30 and 31 of July th of July

35 Indian Black-outs 30 and 31 of July st of July

36 31th July Blackout in numbers Pre disturbance: 48000MW of load not served Defence plan NR officially has loadshedding: AUFS: 4000MW ROCOFS: 6000MW A lot of these relays were never installed because of political intervention, as access to electricity equals economic growth ==> Extreme NIMBY behaviour!!! Equivalent energy needs of 680 Million People!!! During Blackout 9% of world population had no access to electricity!!! Largest Blackout ever!!!

37 Cases in Belgium

38 Cases in Belgium S

39 Cases 1: Belgium, Lint - 21 July 2003 Geographical location

40 Cases 1: Belgium, Lint - 21 July 2003 Downburst

41 Cases 1: Belgium, Lint - 21 July kV double circuit line: 2 towers fallen, 1 damaged

42 Cases 1: Belgium, Lint - 21 July 2003 Tower P4M (86m) on car, home, road

43 Cases 1: Belgium, Lint - 21 July 2003 Tower P5M

44 Cases 1: Belgium, Lint - 21 July 2003 Conductor broken by consequence (on railway)

45

46 Belgium, Achêne & Tihange 14 July 2010 Geographical distance 45 km

47 Belgium, Achêne & Tihange 14 July 2010 Series 1 and 3 (16h36 16h37) neighbourhood Achêne 3 towers down 380kV 6 towers down 70kV

48 Belgium, Achêne & Tihange 14 July 2010 Line Achêne-Gramme

49 Belgium, Achêne & Tihange 14 July 2010 Lines 70 kv around Dinant

50 Belgium, Achêne & Tihange 14 July kV Gramme-Tihange at 16:57 (20 min after series 1,2) 3 towers to replace: conductor 150kV fell on line 70 kv Less redundancy of auxilaries Tihange ==> reconfiguration to restore

51 Belgium, Achêne & Tihange 14 July 2010 Lines &

52 Protecting the system

53 Protecting the system Reliability, but not at any cost The TSO needs to optimize the operational grid situation by looking at the best quality/ continuity of the provided services at the best cost plus penalties ratio R = P*S (R = risk / P = probability of the event / S = Severity) C = R* (C = cost / = estimated cost of non - feeded energy) Iso-risk curve: This curve is truncated for high probability and high impact events ==> Which contingencies is the power system designed for?

54 Protecting the system: Defence plan In case of HILP-contingencies (High Impact Low Probability) The consequence is usually not limited to the own zone The system can evolve to the blackout state

55 Protecting the system

56 Conclusions Blackouts occur Not every outage is a blackout Prevention is done through a combination of foreseeing all possible contingencies, correct procedures to manage them and to avoid (human) error It is not feasible to build a system that is completely free of failures

57 Thank you for your attention!! Questions?