FUTURE POWER SUPPLY

Te Awamutu Courier, Volume 73, Issue 6282, 16 September 1946, Page 5

FUTURE POWER SUPPLY

SURVEY ..WORK NEARING COMPLETION ■ ■ ? . ■ ’ , . DIG' ELECTRIC TRANSMISSION. A SCHEME B'KG'UN - - Survey, .work is practically finished, apjd a start has been made in'cutting tracks over rough country’ for the 22C‘,000-volt main transmission line which is scheduled to-be built down the centre of the North Island/ by 1949-50, to be ready to carry the power load which will be generated on the completion of the Mafaetai hydro station, due to come into operation in 1950-51. This is the biggest transmission project ever planned l in New Zealand. It is a complete new system, which will have double the capacity of the .existing transmission linei ( Tbe latter/* y^lll.. retained' If^/‘distfributjbn; •ppebpses,, ? A/b.ut“. 'lhej -pkwl . tiri'e/' is* ’designed to carry) 800,000 KjV.A., tlie whole load which ‘.will come from the chain of Waikato, generating stations when they are completed.

The new transmission line will start at Otahuhu and run direct to the Whakamaru power station, which will be the central distributing centre for the Waikato system, feeding north and south. From Whakamaru the line will come straight through the centre *of the North Island to Bunnythorpe, taking a route entirely different from, the present . 110,000volt line. There will be no intermediate substations. Three lines will be built over the route, the first of them to be put in hand immediately materials arrive. Steel contractors are now fabricating the 1300 towers which are on order for "the line. Some of these towers will be 80ft. high, and they will be spaced at an average of 18 chains, or 4£ towers to the mile, compared with the spans of 16 chains on the existing line. Insulators of the suspension type will have 14 discs compared with the seven discs of what even now seem outsize insulators on the present line; and 54,600 of these discs will be required. Very careful consideration of wind stressing has been required in planning the line. These are of more importance than* weight, which can be distributed.

At Bunnythorpe the load will be broken down for distribution through the present 110,000-volt line to Wellington, but later a 220,000-volt line will be built from Bunnythorpe to the Hutt Valley, with a substation near Haywards.