Ash, dust or other contaminants on insulators are not believed to have caused the flashover at Morwell terminal, with preliminary results of an investigation showing no causal link.
Energy Safe Victoria launched an investigation into the events at and around the terminal on Friday, 4 April, which caused more than 80,000 Gippsland homes to lose power.
Energy safety director Paul Fearon said a team of specialist electrical engineers and investigators visited the site and were reviewing the circumstances surrounding the event.
Mr Fearon said preliminary results of its investigation were expected to be released by mid-May with a final report later this year.
“It is standard practice for ESV to undertake a review of the circumstances surrounding events such as this to determine, among other things, conformity with the approved Electricity Safety Management Schemes relevant to the network businesses involved,” he said.
Mr Fearon said once the investigation was complete ESV would take enforcement action if it was deemed appropriate.