Friday, 28 June 2013

Powerlines Goose-proofed

by Craig Marshall

Residents of Waitati, Purakaunui, Osborne and points in-between may have noticed brief interruptions to the power supply over the last few months. Typically, at dawn and dusk, the power shuts off for a few seconds before coming back on.

The surprising cause of this is geese and swans. According to Terry Jones, Network Manager, OtagoNet "swans and geese are flying off Blueskin Bay [the estuary] and colliding with the 33,000 volt line that runs along the seaward side of the railway line just north of the Waitati turn off". Because of their size, these birds "are large and heavy enough to push two of the wires together causing the fault and the momentary interruption while our automatic system detects the fault and restores the power".

The solution was to raise the central wire above the others so that they would not touch after a collision. This was done on 19 June and accounts for the planned interruption to supply that afternoon. The poles are in wetlands and so the work had to be done at low tide. Land-based poles can be modified 'live' but the specialised trucks needed for this couldn't be used in the salty mud.

Terry Jones commented, "We are hopeful this solution will eliminate the problem as a similar fix has successfully been implemented in other areas where geese were a problem. Please bear with us in the meantime and accept our apologies for these interruptions."

The effect of these collisions on the geese and swans is not recorded but is probably not happy.

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