An expert's analysis of the the Pomborneit power lines has identified three separate instances of broken strands due to clashing and arcing.
FIVE experts have given evidence in the Supreme Court backing eyewitness testimony that there was a moment of arcing and clashing on power lines before the Black Saturday fire at Weerite and Pomborneit.
Expert testimony began in Warrnambool yesterday in a class action against Powercor over the February 2009 fire.
Dr Trevor Blackburn, called as one of five experts for plaintiff Terrence Place, said arcing power line flares were normally blue but changed to yellow before disappearing.
The court heard two weeks ago from dairy farmer Kerry Lynne Callow, of Macarthur, who testified she was driving along the Camperdown side of the Weerite overpass on February 7, 2009, when she saw a blue flare from a power pole which lasted for two or three seconds.
She said the flare was on the left side of the road and rolled back with a yellow flame before it disappeared. Dairy farmer Regina Beal, from Weerite, also testified she saw a large, bright, metallic flash of light near the start of the overpass.
Dr Blackburn, a visiting associate professor at the school of electrical engineering and telecommunications at the University of New South Wales, said Ms Callow’s testimony was consistent with the behaviour of an arc and was an excellent description.
Dr Blackburn also identified on the power lines three separate instances of where strands had broken because of clashing and arcing.
Asked by Justice Jack Forrest if it was his opinion there had been an arcing and clashing event, Dr Blackburn said he was absolutely convinced.
He said the two witnesses had described an arcing event extremely well.
“The only way to get that sort of arcing to occur would be the clashing of the conductors,” he said.
Expert witnesses called by counsel representing the plaintiff, Henry Hawes, Professor Alex Baitch and Dr John Price, all said they agreed with Dr Blackburn’s evidence.
Mr Hawes told the court he had 38 years of experience in the design, construction and maintenance of power lines and said there were three incidents which confirmed to him that there was arcing and clashing on the line. He said eyewitness accounts of arching and clashing, the voltage dip which resulted in flickering lights at the nearby CFA station and the damage recorded after an inspection of the site “all support each other”.
The case is continuing.
