I)— -

The following table gives an analysis of both accidental and pre-arranged shutdowns :

Faults and Shutdowns on Departmental System

B. OPERATION AND MAINTANENCE 1. Power-stations Cohb. —The peak load carried by the Cobb generators was 11,920 kW. at 1730 hours on Tuesday, 20th July. The annual load factor for the station was 58 per cent. To reduce the possibility of flood damage the level of Lake Halley was lowered and maintained 6 ft. below crest level from the end of June until the middle of November. The annual rainfall was 76-64 in., compared with 92-21 in. for 1947-48. The spears, nozzles, and turbine buckets of all the machines were repaired. The main valves also required some repairs, and the governor and bearing oil-pumps were overhauled. The following table shows the running-times of the various machines :

Machine-running Times

Stoke Diesel Station. —As additional storage was available in the Cobb Valley, the station generated 168,540 units, which was only 21-8 per cent, of last year's generation. The badly-needed overhaul is still held up for necessary parts. The machine-running times were No. 1 machine, 276 hours (53,990 units); No. 2 machine, 285 hours (114,550 units).

25

Year Ended 31st March, 1949. Year Ended 31st March, 1948 Description. Distribution (Total). Accidental . Prearranged Duration. Authorities Affected. h. m. 1. 66 kV. lines : Defects 3 2 2 17 1 2. 66 kV. lines : External causes 2 12 31 1 3. 11 kV. lines: Defects 4. 11 kV. lines : External causes 2 2 03 5. Lightning 4 0 58 3 6. Storms 7. 6-6 kV. apparatus 8. 11 kV. or 33 kV. apparatus 4 26 44"28 3 9. 66 kV. apparatus 1 0 05 1 10. Generators 11. Relays 4 2 24 3 12. Control circuits and batteries 13. Operation : Mistakes 14. Operation : Accidents 15. Faults and overloads on consumers' 15 10 17 *2 systems 16. Other causes 7 17. Causes unknown 3 0 11 i Totals 19 33 30 75 14

Time on Load. Time Idle. Time Under Repair. Percentage Generator. Hours. Percentage. Hours. Percentage. Not in Demand (Hours). In Demand (Hours). Availability for Service. 1 2 3 '.'. 4 6,676 6,890 6,839 6,705 76-3 78-7 78-1 76-5 1,730 1,430 1,753 1,736 19-7 16-3 20-0 19-8 354 435 166 319 5 2 96-0 95-0 98-1 96-3