UPDEA Scientific Committee Workshop Leonardo Pittorino Chief Engineer: Tx Performance

1. Performance Indicators for the Transmission NetworkTo improve performance and set up standards for best practice UPDEA Scientific Committee Workshop Leonardo Pittorino Chief Engineer: Tx Performance pittorl@eskom.co.za

2. The Eskom electrical network • 28 000km transmission lines • 765kV: 1 150km • DC 533kV: 1 035km • 400kV: 16 070km • 275kV & 220kV: 8 620km • 132kV: 1 050km • = 150 000ha servitudes

3. Africa is a tough place…

4. …where our equipment impacts on the environment

5. … while other times we are impacted by the environment

6. … a place where our towers need to withstand large forces 88kV Transmission line 1912

7. … a place with plans for the future

8. Contents • Technical KPIs • NOI, SM<1,Major Incidents, SM<1, SAIRI, Unplanned unavailability, Line faults • Line faults • Right of way management • Bird projects • Fire management • Lightning & weather • Best Practice • Asset management & performance management

9. High Level Overview of Tx Operational Process and Measures

10. Number of Interruptions (NOI) Aim:- To report the total number of interruptions experienced on the Transmission network. Definition:- This measure is a count of the number of Interruptions > 22 kV, measured over a moving 12 month window. Important consideration: The measure excludes incidents caused by Generation, Distribution or other Customers where the impact only affected them.

11. NOI Performance

12. System Minutes < 1 Aim:- To report the total system minutes lost for all the interruptions (other than major events) experienced on the Transmission network. Definition:- This measure is the sum of system minutes lost per incident over a 12 month moving window. Only system minute events less than 1 system minute are counted in this index and only interruptions occurring as a result of system incidents are counted. This measure describes the severity of the load interrupted over a 12-month period. Important consideration: The measure excludes incidents caused by Generation, Distribution or other Customers where the impact only affected them. Note: 1 SM is the loss of the system peak demand of the previous reporting period for 1 minute.

13. SM<1 Performance

14. Major Incidents Aim:- To report the number of major incidents experienced on the Transmission network. These represent events that are so significant that they would otherwise swamp the underlying interruption performance measure (SM<1). Definition:- A Major Incident is an interruption incident that results in the loss of 1 system minute or more. Major Incidents are further categorised by the degree of severity of these incidents: • Severity Degree 1: System minutes lost ≥ 1 and < 10 • Severity Degree 2: System minutes lost ≥ 10 and < 100 • Severity Degree 3: System minutes lost ≥ 100 Important consideration: The measure excludes major incidents caused by Generation, Distribution or other Customers where the impact only affected the customer that caused the incident.

15. Major Incident performance

16. SAIRI Aim:- This index is a measure of the average time taken to restore supply Interruptions. It is measured over a 12 month moving window. Definition:- Sum of Individual Interruption durations in Minute(s) Sum of the number of Interruptions Important considerations: • Momentary Interruptions are excluded from this measure. • Interruptions less than or equal to 22kV are not included in this measure. • Major Incidents are excluded from this measure.

17. SAIRI performance

18. Unplanned circuit unavailablity Aim:- Unplanned Circuit Unavailability is a measure of when plant trips or when it is switched out to repair a fault that would otherwise have eventually led to a trip. It is measured across all Transmission Circuits (Transformers, Lines, etc.) over a 12 month moving window. Definition:- Important considerations: • If plant is switched out only to afford a customer the opportunity to do maintenance work on their side, it is still available. • If a transformer is switched out to prevent it from overloading, it is not available. • If plant is switched out for voltage control, it is still available.

19. Unavailability performance

20. Line faults

21. Line fault Trends 1993 - 2008

22. Breakdown of line faults 1993 - 2008

23. Daily occurrence of faults

24. Seasonal occurrence of faults

25. Right-of Way Management • Bird/animal interaction • Vegetation interaction • The role of lightning & climate

26. Strategic intent • Ensure minimum Environmental impact • Ensure Optimal performance of system • Manage the interaction between the power line and its surroundings

27. Bird interactions • Collisions & electrocutions • Pollution and streamers

28. Collisions

29. Flapper devices

30. Fitting by helicopter

31. Bird Streamers

32. The Streamer

33. Size does matter…

34. Birds do it on our towers

35. Streamer experiment

36. Streamer electrocutions

37. Bird type faults

38. National Bird guard project

39. Perch Management

40. Problems with steel

41. Typical bird guards

42. Bird faults all lines

43. Vegetation Management

44. Management of Vegetation • Ensure Safe Electrical Clearance • Ensure Access to the line • Reduce fuel for Fires

45. 765kV line trip case study

46. Alpha-Beta 765kV line trips • 11:48 29/07/2002 Alpha-Beta 2 trip & L/o Virginia area • 12:29 29/07/2002 Alpha-Beta 1 trip & L/o Standerton area • Two fires were 295 km apart • Previous trip history for these lines: • 2 faults Sept 1994 Alpha-Beta1 • 1 Fault July 1999 Alpha Beta 2

47. Conditions on Monday 29 July 2002

48. The Standerton fire

49. flashover

50. Low fuel loads!