A bullet is most likely to blame for bringing down the Salt Creek wind farm transmission lines at Noorat last month, an independent report has found.
A bullet casing was found near the downed powerline, according to a spokesman for AusNet Services, who operates the line.
AusNet Services commissioned the report which found the fallen powerlines may have been an act of vandalism.
"The damage is consistent with impact by a bullet from a firearm," the report says.
"The most likely cause of insulator damage is impact by external object.
"This could be due to a large object with relatively low velocity or a small object with high velocity and may be an act of vandalism."
An AusNet Services spokesman said the company welcomed confirmation the incident was "not the result of a defect with the Salt Creek Wind Farm transmission line" and that "safety mechanisms on the line operated successfully".
"We are extremely concerned about the safety risk created by the act of vandalism which likely caused the damage," the spokesman said.
"If, as supported by this investigation, the damage was caused by a vandal using a firearm, both the safety risk to that person and the consequences for the local community could have been incredibly severe."
Energy Safe Victoria said in a statement that it would carry out further examinations to fully discount the possibility of any other cause of the collapse, such as manufacturing.
However, it said it did not dispute the analysis and broadly supported the conclusions of the report's author who was well regarded in the industry.
"ESV will also require AusNet Services to review its management of the incident and its future practice to see what may be learned from the incident," it said.
Leading Senior Constable Paul McLean, of Mortlake police, said the incident was being investigated.
The report found that when the fault on the line happened at 10.56pm on March 20 the wind farm was not generating because there was no wind, and therefore no load on the line.
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Read more: Concerns over downed transmission lines
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