Report on the Western Cape outages for the period November 2005 to February 2006

2 Event Analysis method Evaluated conformance to planning and operating procedures and/or instructions Evaluated licence conditions and adherence thereto Analyzed report and documents for root and direct causes Analyzed the protection system operations to confirm sequence and cause of events Evaluated maintenance practices and policies for the affected equipment and units (e.g. transmission lines) Evaluated feasibility of the recovery plans Established trends in the events analyzed.

3 Incident of 11 November 2005 Switching operations at Koeberg substations resulted in the tripping of several lines and Koeberg Unit 2 Root cause - Latent defect open circuit on the isolator Findings –Negligence resulting from set procedures and instructions that were not carried out on the day –Inadequate maintenance procedures that cannot detect visible defects –Breach of the licence condition - failure to island of Koeberg Unit 2 (incorrect configuration of the relay) –Incorrect protection system operation, resulting in unnecessary loss of load

4 Incident of 12 November 2006 A piece of wire that was dropped by a crow whilst building its nest resulted in the tripping of the Beta-Hydra line and associated transformer as well as the auxiliary power supply to the Koeberg Unit 2 Root cause – protection malfunctioning due to incorrect configuration of the measurement transformers Findings –Maintenance and/or commissioning procedures are inadequate –Protection co-ordination incorrect

5 Incident of 16 November 2006 Fire under the Droerivier-Muldersvlei 2 line tripped the line causing a voltage depression that tripped Koeberg Unit 2. Direct cause – malfunctioning of the protection system and failure of the tele-protection equipment. Findings –Breach of the licence condition - failure to island of Koeberg Unit 2 (incorrect configuration of the relay) –Implementation of corrective measures inadequate (correction recommended in 2002 but not implemented)

6 Incident of November Controlled shutdown of Koeberg Unit 2 due to out of specification chemical concentration in the safety injection accumulator Direct cause – failure to notify the authorities that the adverse boron concentration went below the chemistry specific target value Findings –Negligence in not notifying the authorities and allowing the acid concentration to go out of specification –Inadequate operating risk assessment processes

7 Incident on February 2006 On the 18 th February the Kendal power station unit 6 tripped causing a severe frequency drop that resulted in the sympathy tripping of the Koeberg Unit 2. On the 19 th February various lines and substations experienced insulation flashovers that resulted in the tripping of numerous transmission lines and substations Direct cause – The Koeberg Unit 2 tripped due to loss of excitation and the insulation failures were induced by excessively dense and highly conductive mist Findings –Inadequate maintenance procedures and policies for transmission lines and substations –Negligence in not coating and/or washing of the insulators in time. –Licence conditions breached with regard to frequency limits

8 Incident of 28 February 2006 The Bacchus-Droerivier line tripped resulting in the isolation of the Western Cape Network. Koeberg Unit 2 successfully islanded and tripped as it was being reconnected to the main network Direct cause – Insulation flashover on the Bacchus-Droerivier line due to heavy mist resulting in the breaking of the insulator and subsequent falling to ground of the line. Findings –The corrective measures on the protection configuration were correctly implemented resulting in the correct islanding of the Koeberg Unit 2 –Co-ordinatio of protection & tele-protection was inadequate –Maintenance procedures & policies inadequate for prevailing conditions –Negligence in not washing the lines in time, given the warnings

9 Future plans & supply security Western Cape Recovery Plan –Additional generation of 1050MW by 2007 for the Western Cape –Demand Side Management initiatives –Koeberg Unit 1 restoration –Demand Market Participation and co-generation –Additional mobile generators where required Findings –Plans and initiatives adequate for the short to medium term

10 Summary of Events & Conclusion Events of 11, 12 & 16 November 2005 mainly resulted from incorrect protection systems operation and configuration causing transgressions of the licence conditions. Events of 19 & 28 February resulted from inadequate transmission lines and substation maintenance practices and policies Events of 23 – 26 November resulted from the negligence and ill discipline of the responsible personnel. The implemented corrective measures are adequate as well as effective and have resulted in the correct operation of the relevant protection systems and hence conformance to breached licence conditions. The measures taken to ensure the security and continuity of supply are adequate and sufficient for the short to medium term.

11 THANK YOU