AN ERROR during a routine inspection of a transformer at a Tamworth electricity substation has been blamed for the widespread blackout which hit Tamworth and surrounding towns yesterday morning.
Shops shut their doors, residents were left in the dark with no kitchen facilities and big business employees ran to their generators as 33,000 homes and businesses were affected.
A broad area of the North West was affected, with Willow Tree, Quirindi, Barraba, Limbri and Manilla among centres knocked out.
TransGrid general manager of system operations Neil Smith said the switching operation was a daily routine for the 330kV Burgmanns Ln substation on the outskirts of Tamworth.
The power outage occurred when a staff member attempted to isolate a transformer at the substation.
“Protection equipment switched out automatically, which cut the supply to Tamworth and the surrounding areas,” Mr Smith said.
“It’s an operation that’s carried out every day, normally when the transformer is undergoing a routine inspection.”
The error resulted in the loss of about 50MW of electricity in just under an hour.
“We went from 330,000 volts to 132,000 volts,” Mr Smith said.
Mr Smith said it was “very rare” for a major error to occur, saying it only happened a few times each year.
There were no health and safety issues, as the operation was carried out remotely.
He met with two or three staff members yesterday afternoon to investigate the issue.
“I’ll be interviewing staff to find out what happened so that we can prevent a recurrence,” Mr Smith said.
While the outage only lasted an hour, it was enough to turn the Tamworth CBD into a scene of chaos as police scrambled to direct traffic in busy intersections where traffic lights were shut down.
The scramble was made worse as early news from power authorities suggested the blackout could last up to four or five hours.
Supermarkets were forced to take measures to preserve their perishable goods, with some having to turn away delivery trucks until the chaos was over.
Some businesses sent employees home for the day while others waited for news on when the power would be restored.
Other big employers sent staff home for a temporary period with instructions to report back at 12.30pm.
But the return to work was hastened when Essential Energy flicked the switch and progressively turned power on to affected homes just before 10am.
But the hour without power was enough to spark a flurry of confused posts on social media, with many turning to Facebook and Twitter to make sense of what had happened and where.
Essential Energy spokesman David Crough said the first priority for the energy giant was to restore power to affected homes before an investigation began into how the fault happened.
“What happened is we lost a main power line into Tamworth. It’s quite widespread and quite an important line,” Mr Crough said.