1. Impact of Hurricane Ike on
CenterPoint Energy’s
Transmission System
Paul Rocha
Director, Transmission Planning
Presented at October 2, 2008 ERCOT TAC Meeting

22. Hurricane Ike 9/12/ PM
Energized
Out
Restored
0 Circuits Out

23. Hurricane Ike 9/12/ PM
Energized
Out
Restored
14 Circuits Out

24. Hurricane Ike 9/13/2008 2 AM - Landfall
Energized
Out
Restored
36 Circuits Out

25. Hurricane Ike 9/13/ AM
Energized
Out
Restored
67 Circuits Out

26. Hurricane Ike 9/13/ AM
Energized
Out
Restored
90 Circuits Out

27. Hurricane Ike 9/13/ PM
Energized
Out
Restored
97 Circuits Out

28. Hurricane Ike 9/13/2008 Restoration – 7%
Energized
Out
Restored
7 Circuits Restored
90 Circuits Out

29. Hurricane Ike 9/14/2008 Restoration – 41%
Energized
Out
Restored
40 Circuits Restored
58 Circuits Out

30. Hurricane Ike 9/15/2008 Restoration – 70%
Energized
Out
Restored
70 Circuits Restored
30 Circuits Out

31. Hurricane Ike 9/16/2008 Restoration – 87%
Energized
Out
Restored
87 Circuits Restored
13 Circuits Out

32. Hurricane Ike 9/17/2008 Restoration – 94%
Energized
Out
Restored
94 Circuits Restored
6 Circuits Out

33. Hurricane Ike 9/23/2008 Restoration – 100%
Energized
Out
Restored
100 Circuits Restored
0 Circuits Out

34. Pole Damage

35. Pole Replacement

36. CenterPoint MW Load Restoration

37. Seawall Substation

38. Stewart Substation

39. West Bay Substation

40. Moody Substation

41. Galveston Substation

42. West Galveston Substation

43. Mobile Substation

44. Network Changes
After reviewing damage assessments and analyzing power flow study results, CenterPoint Energy decided not to restore the 69 kV portion of damaged West Galveston substation and 69 kV Ckt. 13, Lamarque – West Galveston
Removal of damaged 69 kV connections to Galveston Island could cause some increased loading on remaining three 138 kV connections to Galveston Island
Timing depends on rate of load restoration and growth on Galveston Island
CenterPoint Energy believes upgrades of remaining 138 kV facilities would be more practical, cost-effective, and timely than restoration of damaged 69 kV facilities
CenterPoint Energy will evaluate upgrades to remaining 138 kV connections to Galveston

45. Galveston Island Network Changes - Temporary

46. Galveston Island Network Changes - Permanent

47. Emergency Entergy Connection
Implemented emergency interconnection from CNP’s Crosby substation to Entergy’s Dayton substation 9/15/2008
From Dayton substation, CNP used new transmission line built by Entergy after Hurricane Rita to restore power to water plant on the Trinity River normally served by Entergy
Disconnected Entergy emergency connection 9/19/2008

48. Planned Transmission Outages
Deferred all planned outages during restoration process
CenterPoint Energy expects to resume planned outages next week

49. Thank You!!! Mutual Assistance
No report would be complete without noting the tremendous mutual assistance support from other utilities across North America
Far too many to list here, but we want to say…
Thank You!!!

50. Transmission Network Summary
Transmission Network Was Quickly Restored
Network restored to necessary functionality within 4 days
However, storm surge affected Galveston Island, including CNP substations
Grid stability maintained despite tie-line and other outages
ERCOT actions to adjust for increased probability of line outages was effective
Generators performed well
2007 completion of STP– Hillje– WAP tie-line helped
Availability of mobile substations aided restoration effort
New Entergy 138 kV line expedited water plant restoration
Relay and Control infrastructure performed well
Hurricane training and drills were effective in preparing personnel