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(a) Transmission-lines. The Waihou-Paeroa 50 kv. line and switching-structure at Paeroa were completed early in the year. Survey of New Lines. —New 110 kv. lines are being surveyed as follow :— Arapuni-Edgecumbe-Murupara portion of the Arapuni-Waikaremoana Line : Survey practically complete, and pegging of pole positions to Edgecunibe commenced. Arapuni-Penrose Second Steel-tower Line: Work of contouring angle positions was carried out. Henderson - North Auckland: Detailed survey of both power and telephone line are now practically complete. Arapuni-Stratford : The survey of the selected route was practically completed, and plans prepared for location of pole-positions. A good deal of work is still to be done in investigating foundations in papa country. Poles and wire have been ordered for construction of part of this line. (d) Substations. Penrose (110/22 kv.—60,000 kv.a. capacity; 22/50 kv.—5,000 kv.a. capacity).—The installation of capacitors and protective relays for the three incoming 110 kv. lines was completed. Three additional switch-gear panels arrived, and erection of them was commenced. The Power Board's cable to No. 4 panel was connected up in November, 1930. Tahapuna (50/11 kv.—2,000 kv.a.). —New bank of transformers (four 750 kv.a. single phase) arrived, and transported to the substation. Waihou (50/11 kv.—2,250 kv.a.). —The 50 kv. transformer 0.C.8. was installed, also the turntable, completing the present installation. A house was built for the operator. Hamilton (50/11 kv. —3,000 kv.a.). —The motor-generator set for battery-charging and the control panels for No. 2 Substation were erected. The control cables to No. 2 Substation were laid underground. Bombay (110/50 kv. —5,000 kv.a. ; 50/11 kv. —3,000 kv.a.). —Two new feeder cubicles were installed by the Franklin Power Board. A second bank of transformers (three 500 kv.a.) arrived, and were put in service on 23rd December, 1930. (e) Huntly Power-station. One 1,500 kw. steam turbine, 3,000 r.p.m., 550 volts; three 623 kv.a. transformers, 550/11,000 volts. On the failure of Arapuni in June, 1930, it was decided to remove the above turbine-set from the Grand Junction plant at Waihi, and re-erect it at Huntly. The turbine was run up to speed on 27th March, 1931, and operated very satisfactorily. 4. Operation and Maintenance. (a) Power-stations. Hordhora. — This station operated satisfactorily throughout the year and the usual routine maintenance repairs were effected as opportunity offered. Arapuni. —The failure of the headrace at Arapuni, which resulted in the closing-down of the power-station on 11th June last, was dealt with in the last annual report. Since then the power-house machinery and apparatus has been maintained in good order by the use of electric heaters and calcium chloride where necessary to ensure dryness. Penrose Diesel Plant. —The plant has operated successfully during the year. The new spray pond in conjunction with the cooling-tower, enabled all three engines to be run for long periods without excessive cooling-water temperatures, supplying load up to 3,980 kw. maximum, with weekly output up to 320,000 units. Grand. Junction Steam Plant. —This plant ran satisfactorily during the year, and carried up to 3,000 kw. load in June, 1930, after the failure of Arapuni. After September, 1930, only the 1,640 kw. unit was available to supply power. (b) Transmission-lines. 110 kv. Lines. —Further work was done during the early part of the year in improving towerfoundations in clay country. There were no outages due to line-faults during the year. 50 kv. Lines. —There were only four cases during the year of failure of insulators in service causing interruption, all of these being on the old Horahora-Waikino line, three being pin insulators and one a strain insulator string. Bombay-Kerepeehi-Waikino Line : A big improvement in telephone operation on this line was effected by rearranging the transpositions to get better balance. Horahora- Matamata-Waikino: The dismantling of the Half-way-No. 8 hut portion-of this line was completed early in the year. Ngongotaha- Edgecumbe- Waiotahi: On 2| miles of this line near Tikitere, 7/14 S.W.G. copper wire, which was being affected by sulphur fumes, was replaced with 7/13 S.W.G. galvanized iron, painted with sulphur-resisting paint. Inspection of a length of one mile, which had been previously dealt with in this way, showed that the wire was in good condition. (c) Substations (Sixteen). Penrose, Matamata, Waihou, Waikino, Huntly, Bombay, Waiotahi, Henderson, Takapuna, Hamilton, Te Awamutu, Hangatiki, Kerepeehi, Mamaku, Ngongotaha, and Edgecumbe: Nothing of importance to report.

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