Two global experts have found Tasmania’s undersea Basslink cable failed because it was run for too long.
Expert reports provided to the company have concluded the Basslink cable link failed because Basslink Pty Ltd (BPL) operated it in a way that allowed the cable to exceed its temperature design limits, with the overheating and subsequent cooling of the cable causing it to degrade.
Hydro Tasmania, CEO, Steve Davy, said, “Issues related to heating and cooling of the cable under operational stress likely caused caused the December 2015 failure.
“BPL believed its cable could safely and reliably operate at 630MW for extended periods without overheating the copper and insulation and causing an unreasonable likelihood of failure.
“Unfortunately, they were wrong. The expert reports note that the cable, as designed and constructed, cannot meet the minimum operating requirements.”
Mr Davy said the reports recommend limiting the state’s energy export capacity to 500MW.
“The experts are confident Basslink can safely and reliably operate at 500MW,” Mr Davy said.
“The expert investigation identifies the probable cause of the cable failure. But most importantly, it also identifies both interim and long-term solutions to ensure Basslink can operate as reliably as it was supposed to in future.”
Hydro believes adopting that level, will ensure safe and reliable operation of the cable to support Tasmania’s contribution to Victoria’s energy supply over the 2017/18 summer.
“The Basslink cable is the sole responsibility of its owner. It’s now incumbent on BPL to consider the reports and take the necessary steps to improve its cable to the standard and specifications promised.”
Mr Davy said the findings vindicate Hydro Tasmania’s decision to conduct its own investigation.
“We’re confident this expert investigation solves the mystery of the Basslink failure for all Tasmanians,” Mr Davy said.
The reports have been submitted to BPL.
Hydro Tasmania intends to release the DNV GL reports to the public in early 2018.