D.—l

Reliability of Generating-units.—The operation of the main generating-units at Mangaore was satisfactory throughout the year, and the records of reliability as compiled for previous year's have been kept up to date. (b) SUBSTATIONS. Bunnythorpe.—Operation was satisfactory throughout the year. During the year several cracked post insulators were changed. The automatic-telephone-exchange equipment was overhauled. Dannevirlce.—One interruption of importance occurred on the 12th November, when an earthquake release clamp pulled oft in a heavy gale. A general renovation and painting of buildings was completed during the year. Gisborne. —This substation gave satisfactory operation during the year. 400 volt and telephone-line renewal work was carried out and a new distribution board installed. Hawera.—ln December a fault on Power Board bus-bars due to lightning caused an interruption, during which the main 11 kV. switch was cleaned out. Khandallah.—Modifications were made to the 11 kV. switchgear. An adjustable platform truck was made for the handling of potential transformers of various sizes. Burning was found in the amortisseur windings of the synchronous condenser and repaired. Mangamaire.—Operation was satisfactory throughout the year. In November a change over was made from No. 2 to No. 1 bank, when all No. 2 switchgear was overhauled. One 110 kV. 0.C.8. bushing was replaced. Masterton.—ln November a flashover on an 11 kV. bushing to conservator tank occurred. One H.T. and one L.T. bushing were replaced. Taps on the transformers have been altered and are now in the position for maximum volts. Marton. —One interruption occurred during the year, when a H.T. fuse blew on the 29th June due to the inability of the station battery to trip the 11 kV. switchgear. The battery was replaced. A new traverser truck was received. Melling.—This substation gave satisfactory service during the year. Napier.—An overhaul of several transformers was made. Several cracked post insulators were replaced. New Plymouth. —Operation at this substation was satisfactory during the year. Metering was altered to meet conditions of the new power contract with the New Plymouth Borough Council. Okato and Opunake. —Both substations were regularly inspected and gave satisfactory operation. In April faulty operation of reclosing-gear occurred, and was found to be due to reclosing relay resetting too soon. Papaparaumu.—This substation gave satisfactory service during the year. Stratford. —A fault occurred in February in the condenser main switch cubicle due to a mouse. All transformers and switchgear have been scraped and painted. Special earth-leakage relays were fitted. The Merz-Price potential transformers in the synchronous condenser switchgear were replaced. A ringing repeater has been installed on the high-tension telephone. Waipawa.—A new local service board was fitted up and put into service, and 0.C.8.s have been overhauled. Wairoa. —During the past year transformers were overhauled. A new 11 kV. bus was installed. Wanganui. —This substation gave satisfactory performance during the year. Woodville. —One fault occurred during July on an A.B.S. and was repaired. Four post insulators were replaced. (c) TRANSMISSION-LINES. (i) 110 kV. Mangahao-Khandallah Duplicate Lines.—Throughout the year a pole-to-pole inspection and overhaul was carried out; a number of insulator units were changed. In November a complete shutdown took place when an aeroplane damaged both east and west lines, and in January a special patrol and cleaning were carried out when salt spray trouble caused serious interruption to supply. Arrangements have been made to reinsulate the west line, MangahaoPaekakariki, to endeavour to overcome the salt trouble. On the telephone-line a general overhaul and rewiring was carried out. Between Mangaore and Otaki River the line was rewired with No. 6 copperweld on the twist system. This will eventually be carried on to Paekakariki, so that the whole line will then be copperweld. Four interruptions on the telephone-line during the year were due to break on a transposition near Orchard, broken wires at Horokiwi and Brandon Hut, and a faulty transposition near Manakau. Khandallah-Mtilling. —This line gave satisfactory service during the year. Mangahao-Bunnythorpe Duplicate Line.—This line operated satisfactorily. A pole-to-pole inspection and overhaul was carried out, and pole-capping was completed. A deviation was made in the line at the main North Trunk Railway line by Palmerston North. Further work was done on the Manawatu River protection groynes. A general overhaul and rewiring of the telephone-line was carried out, cadmium copper (with cork dampers) replacing copperweld on the Manawatu River-Bunnythorpe section. Bunnythorpe-Marton-Wanganui.—This line gave satisfactory service throughout the year. An overhaul was completed from last year and the fitting of " Armour rods " to all suspension clamps finished. Protective work was done at the Oroua River crossing. Telephone Line : Three faults occurred, two from broken crossarms near Bonny and the other from slack wires at Marton twisting. Work on the line for the year included a general overhaul and retensioning of wires.

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