THE power supply to the Balaklava district should be more resilient in storm events following a major upgrade of the supply line on Sunday, which required a town-wide power outage for most of the day.

SA Power Networks corporate affairs manager, Paul Roberts, said the lengthy outage was required to complete a crucial portion of the project safely.

“The work in Balaklava on Sunday was part of a major $500,000 project being undertaken in May and June to upgrade the whole of the main 33,000 Volt (33kV) supply line from Hummocks to Balaklava and surrounding areas – a line that is subject to outages caused by lightning strikes on insulators,” he explained.

“We would expect the project to result in improved resilience to thunderstorm events.

“We are replacing the old ceramic insulators with polymer resin insulators that are more resistant to lightning strikes.

“While the old ceramic insulators are hard-wearing and long-lasting they are vulnerable to damage from lightning strikes that can cause an extended outage.

“With the resin insulators, if they are struck by lightning, it is more likely to flashover across the insulator surface to earth causing only a momentary interruption and therefore maintaining supply, rather than when it strikes the ceramic insulators, which are usually punctured, causing a sustained interruption.

“We have been able to carry out much of the insulator replacement work without large-scale outages, but Sunday’s work in Balaklava could not be completed safely by crews without turning off power as we have 7.6kV lines running under 33kV lines in the town.

“There may be some more outages for people on single-wire earth return (SWER) lines in the area as this work continues.

“They will be notified in advance if they are affected.”