Combination of old wires and new technology cause of SA blackout

Photo: Debbie Prosser

The Australian Energy Market Operator (AEMO) has released a preliminary report into last Wednesday’s state-wide blackout in South Australia.

AEMO, under the Australian Electricty Rules, conducts reviews of this nature after significant events that cause major outages.

The AEMO report covered how the storms moved across South Australia last Wednesday, with high winds, thunderstorms, lightning strikes, hail and heavy rainfall which caused in the space of 12 seconds, the loss of three 275kV transmission lines north of Adelaide.

The report found the fallen lines initially carried power, but at 4:20pm, 315 MW of wind generation disconnected and this caused the outage north of Adelaide.

The uncontrolled reduction of generation increased the flow on the main Victorian interconnector at Heywood and caused the interconnector to overload.

The Australian Energy Council (AEC) has responded to AEMO’s findings saying the differences in running a conventional thermal generation system can’t be applied to renewables, which are prone to intermittency.

“Of key importance is how the mix of generation in a high renewables grid responds to events lie the sudden loss of transmission in the mid-north of the state and the supply that it was carrying that triggered events of last Wednesday afternoon,” AEC CEO Matthew Warren said.

“The preliminary report provides clarity around the sequence of events that occurred, but also reveals the need for more detailed information to fill in some of the blanks that will help improve system security into the future.

“It reinforces that we may need to think differently about the potential effect of extreme weather events, given we are now operating a more weather-dependent electricity system.”

The AEMO will continue to analyse the events which triggered the South Australian blackout and provide a further update later in the month.