D.—l.

Service interruptions (other than those prearranged) numbered fifteen, and amounted to 2 hours minutes. Waipukurau. —This substation has supplied power to the Central Hawke's Bay Power Board throughout the year, and all apparatus has functioned well, except during the earthquake on 3rd February, 1931, which caused slight damage, putting the station out of commission for 1 hour 39 minutes while repairs were effected. The damage sustained is mentioned more fully under the report on the earthquake. There were thirteen accidental interruptions to service, totalling 2 hours 3J minutes. Napier. —Hawke's Bay Power Board has derived its supply of electrical energy from this substation throughout the year. This year has been a marked one, owing to the disastroiis earthquake which visited the locality on the 3rd February, 1931, practically wrecking the station. Details of damage done are set out in the report on the earthquake, which caused an interruption to service for 31 hours 5 minutes, power then being resumed at 11 kv. from Waipukurau and Tuai until a temporary substation was erected at Waiohiki. Apart from this, there were thirty-one other accidental interruptions to service, totalling 16 hours 45J minutes. Wairoa. —-This substation during the year supplied power to Wairoa Power Board, and, in general, all apparatus functioned well. The accidental outages numbered twenty-four, of 33 hours 29J minutes duration. The earthquake on the 3rd February was responsible for an interruption to service for 24 hours 32 minutes while repairs were effected. Gisborne. —At this substation, which feeds the Poverty Bay Power Board, the equipment operated well during the year. The earthquake of the 3rd February was responsible for an interruption to service lasting 9 hours 51 minutes. Other accidental interruptions numbered twenty-six, of a total duration of 23 hours 50 minutes. All earthquake damage has now been repaired. Substations : General. At all substations all insulators and bushings on bus-bars and switch-gear were cleaned during the year. Periodical checks were made on all switch-gear, relays, and metering-equipment, and repairs and adjustment made where necessary. The synchronous condensers at Khandallah, Mangamaire, Dannevirke, and Napier were run, when required, for voltage regulation. Transmission-lines (110,000 Volt). Mangaore-Khaniallah Duplicate Line. —During the year there were five outages, totalling 11 minutes, on this line. Three of these, totalling 5 minutes, were due to bird deposits on insulators ; one of 3 minutes to earth-wire, which was being removed from the line, coming in contact with the live line ; and one of 3 minutes to a farmer's wire-ropeway for transporting timber coming in contact with the line. Mangaore-Bunnythorpe Duplicate Line. —This line gave no trouble whatever during the year. The strengthening and replacing of weak poles has been completed during the year from Mangaore to Manawatu River, this section being thoroughly overhauled. The reconstruction of the telephone-line in cadmium copper is in hand, and about ten miles have been wired to the 31st March, 1931. Vibration-dampers were fitted to the cables on the towers at Manawatu River crossing. Bunnyihorpe-Marton-W anganui Line. —This line gave very good service during the year. Sap-testing has been carried out on this line with a view to pole-strengthening being started in the near future. Bunnythorpe-W oodville Line. —This line gave very good service during the year. In connection with the vibration troubles previously experienced on the aluminium cables, vibration-dampers have been installed at various points on the line. All towers were carefully examined for any damage due to the earthquake, but none was recorded. Woodville-Mangamaire-Masterton Line. —No interruptions during the year were attributable to this line, which gave good service. Further excessive wear during the year on the U-bolts on the Mount Bruce towers, and these were replaced where necessary. Woodville-Dannevirke Line. —This line has generally given good service during the year, but a further break on the aluminium jumper at a strain pole has occurred, due to vibration. Vibration-dampers have also been installed on this line on the section where vibration has been responsible for broken cables in the past. Dannevirke-Waipukurau Line. —One interruption to service was caused by this line, a strain-pole jumper breaking, due to vibration. Waipukurau-Napier Line. —-This line gave very good service during the year. Practically no serious damage was done by the earthquake on the 3rd February, but a fair amount of work was necessary straightening cross-arms and replacing weights which had shaken off. The telephone-line also was damaged very little, but the wires were twisted together, making communication over the line entirely out of the question. The damage done was quickly repaired, and the lines made ready for service, power being supplied at 11 kv. from Waipukurau to Napier until the Napier-Tuai lines were repaired.

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