D.—l.

Khandallah - New Zealand Railways Duplicate Line. —There were five accidental outages on this line during the year, of a total duration of 1 hour 31 minutes, two of which, totalling 1 hour 28 minutes, were due to damage following a fault on the Hutt Valley Electric-power Board's lines. Khandallah - Wellington Meat Export Co., Ltd., Line. —During the year there were six outages on this line, of a total duration of 14 hours 19 minutes, three of which, totalling 14 hours 7 minutes, were due to a fractured trifuroating box at Khandallah. Transmission-lines (General). During the year there were thirty-four lightning storms, only seven of which affected the operation of the system. New Plymouth Substation suffered two interruptions, totalling 11 minutes ; Gisborne Substation, one of 2 minutes ; Waipukurau, one of 11 minutes ; and Dannevirke, one of 10 minutes ; the one at Dannevirke being coincident with that at Waipukurau. The Mangaore - Bunnythorpe East line was put out of service on one occasion, and the TuaiNapier lines on two occasions, without affecting supply. All strain and suspension insulators on the system, including those on the substation structures, have been tested by means of the buzz stick, and all defective units changed. Sap tests and inspection of poles have been carried out over the whole system, and weak poles scheduled for replacement. In August of last year during an exceptionally heavy gale three of these weak poles were broken, unfortunately not long before they would normally have been replaced according to schedule. The work of changing weak poles and defective insulators has been carried out by a special gang trained in " live-line " work, and practically all this work has been done with the line alive. This gang has also assisted with the usual routine maintenance of the lines in cleaning insulators, &c. Development work is being carried out on methods for cleaning insulators under " live-line " conditions, but so far no completely satisfactory method has been evolved. All linesmen were given a refresher course in buzz-stick testing in association with the special " live-line " gang. Earthquakes. Following experience gained during the earthquake in the Hawke's Bay and Gisborne districts on the 3rd February, 1931, precautions have been taken at all substations and at the power-houses to prevent any extensive damage to apparatus due to earthquakes. It was found that the only apparatus likely to sustain any extensive damage during earthquakes are transformers and batteries. Transformers have been bolted down to their foundation block and release joints provided in the 110,000-volt connections to prevent damage being done to the bushings. All batteries installed since February, 1931, have been mounted on stands specially designed to hold the cells in place during earthquakes and to prevent any major damage being done to them. During the year three major earthquakes occurred. On the sth May, 1932, a severe shock was felt in the Hawke's Bay District, but very little damage was done. The release joints in the 110,000-volt transformer connections operated, and prevented damage to the bushings. An interruption of 20 minutes was caused to supply at Napier Substation and one of 13 minutes to Waipukurau and Dannevirke Substations. On the 16th September, 1932, a particularly severe earthquake occurred, which was felt over a wide area, though damage was confined almost entirely to the Gisborne and Wairoa districts. Damage was particularly severe in and around Wairoa, where many buildings were destroyed and considerable property loss sustained. The Department's apparatus remained intact, though the building was somewhat strained and the release clamps in the transformer leads were pulled off. These were replaced and power was available at the substation 5 hours 18 minutes after the first shake, though normal supply was not resumed till four days afterwards on account of the damage done to the Power Board's apparatus and lines. At Gisborne the departmental cottage chimneys were shaken down, and the pipes conveying the cooling water to the main transformers were broken. Power was available at the substation a few minutes after the shake, but owing to the absence of telephonic communication with the Power Board staff it was not until 19 minutes after the shake that power was again restored to the Power Board's consumers. The 50,000-volt lines from Waikaremoana to Wairoa and Gisborne were severely shaken, but the damage done was slight, consisting chiefly of the loosening of the earth round the poles. Telephone communication was interrupted for some time owing to the wires being badly twisted. Communication with Gisborne was re-established at 10.30 a.m. on the 16th, approximately 9 hours after the shake. The line to Wairoa suffered more severely, and it was not till 10 a.m. on the following day that the Department's line was again in operation. In the meantime all messages between Waikaremoana and Wairoa were relayed through Napier over the Post and Telegraph Department's line. Direct communication over the Post and Telegraph lines was again restored at 3 p.m. on the 17th. A further earthquake occurred at Wairoa on the 19th October, 1932, but very little damage was done. Injury to the transformer bushings was again prevented by the release clamps pulling off. 111. Construction. Mangahao Power-house and Headworks. —In order to measure the water lost during floods a wastewater recorder was installed at No. 2 dam. During the Christmas - New Year period new gates were installed in the surge-chamber to replace the old ones.

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