Construction Of Power Line To North

Press, Volume CI, Issue 29778, 22 March 1962, Page 12

Construction Of Power Line To North

The first step towards the erection of the £6 million. 500,000-volt transmission line from Benmore to Cook Srait wil! be taken today. Ten works camps to construct this DC power line over 340 miles of plain and mountain are nearly completed after months of roadins and bridging work. Today, a gang of men from the Oxford camp wil) dig the first hole to take a pylon lee in the Waimakariri gorge. This hillside tower on the north bank of the river is about 10 chains upstream from the bridge over the gorge ft will be the first of about TOTO holes to be dug with machines and by hand for some 1600 towers between the Waitaki river and the Strait

The two pairs of cables should be ready for testing at the end of next year and

power should be crossing Cook Strait for the winter of 1965. The New Zealand Electricity Department has about 100 men working on the land line job at present and by early next year expects to increase the force to more than 200. The four legs of each tower will be bolted to a steel grille buried to Bft. Each hole involves the excavation of about 12 cubic yards of earth and rock The steel for the found ation grilles is expected to arrive at the Electricity Department's yard at Islington todaybut the towers, which will be bolted together on the site from parts supplied from Italy, will not go up for two months.

Four cables will be strum? m pairs using the pullins and tensioning machines recently acquired by the department. There will be a toialrun us ' n g the inch and a half cable in June. The machinery, worth

£lOO.OOO and recently used on 70 miles of line from Islington to Geraldine, is now raising lines at Benmore for transmission to Islington. Each foot of the 83-strand aluminium and steel DC cable weighs a pound and three- ?? ,ai li? rs ' span to cross the Waimakariri river will be 28 chains. Its erection should be achieved without any part ot the cable touching the ground. It will reel off the drums on to the machines and up to the pylons Marks on very high voltage line result in a loss of power through a phenomenon known as corona. These will be avoided by the new stringing method. e The 24 miles of undersea KT-lt f ?. carr y Power to the North Island will cost abou* as much as the overland lines and towers. The first eight miles of overhead cable are expected -O go up in June and the next major shipment will be available about October.