D.—l

62

These lines and substations are shown on the map below.

Waikato Electric-power Supply.

Power-house Extensions. —Designs have been prepared for extensions (two 2,000 kw. units) to the power-station at Horahora, and tenders for the supply of the plant for these extensions are. closing early in 1922. Operation Headworks and Power-house. During the Christmas shut-down the opportunity was used to examine the race, and to alter the screens to prevent them being choked by weed and pumice, of which a considerable amount is brought down in flood-time. The indications are that considerable improvement has been effected. The turbines have all been overhauled, and adjustments made which have improved their operation and particularly the governing. Tests have been made on the power-house working on artificial load up to its full capacity. When this was first tried, full load could be maintained only for a few minutes, owing to the badly blocked screens causing the water in the turbine-pits to drop. Since the alterations to the screens the plant has carried full load for several hours without any difficulty, but at extreme low water the most that can be carried is 5,700 kw., showing that to utilize the increased plant capacity at low water it will be necessary to extend the wing-dam and weir at the intake. Provision is being made for this work. Measurements made on the water left in the river at the time of this test indicate that the total power obtainable at Horahora, with reconstructed dam and increased head, is about 8,400 kw. at the low-water period. Transmission-line. Various defects in the transmission-line have been remedied with good results. Some of the towers have been tarred as a protection against the weather, but much remains to be done in this direction. This work is difficult to carry out, as the time during which the line can be made " dead " for this purpose is very short. Interruptions lo Service. Apart from the shut-down for overhaul for 41 hours 7 minutes at Christmas, the total number of interruptions was twenty-three, for a total time of 45 hours 26 minutes ; eight of these were of 1 hour duration or more, for a total time of 38 hours 14 minutes. Three breakdowns only were due to insulator trouble, the rest being due mostly to mechanical faults and defects in apparatus which have been remedied. There have been no troubles on the Thames Valley Power Board's 11,000-volt line, Waikino to Paeroa, or on the 11,000-volt lines from Waikino to the Waihi Mine and the Junction Mine.