SA blackout due to five system faults in 88 seconds

The AEMO has updated its preliminary report into the South Australian statewide blackout and found five system faults occurred within 88 seconds, leading to six voltage disturbances.

South Australia was plunged into blackout on September 28 when severe storms and high winds swept the state.

The AEMO reports 13 wind farms online at the time of the storm did not ride through the six voltage disturbances, resulting in 445MW of energy not being generated.

In preliminary discussions with wind farm operators the AEMO found ‘voltage ride-through’ settings were set to disconnect or reduce output when they experienced between three to six disturbances in a defined period.

Thermal generators remained connected to the national grid, as did the Heywood Interconnector, until a sudden increase in electricity flow caused an automatic protection mechanism to disconnect the lines.

Two contracted SRAS suppliers had difficulty restarting services due to two separate faults, but both facilities tested their restart capacities earlier in the year. For that reason, AEMO will look at the nature of these failures on September 28.

Restoration of electricity had started within three hours of the black system event, with around 80 to 90 per cent of energy being restored within five hours.

Construction of temporary towers and the restoration of three of the four damaged transmission lines saw full power restored from October 12.

The Australian Energy Council (AER) has issued a statement in response to the updated report saying the management of grids with high penetration of renewable energy needs to be reassessed.

Chief executive Matthew Warren said wind farms can be designed to ride through these types of voltage events.

“South Australia is a living experiment in how we manage high levels of renewables in modern electricity grids,” he said.

“It is hard to anticipate and test for real world situations like this until they occur.

“While the blackout was caused by a cascading set of events from extreme storms on the day, the most important thing is we learn from this experience and do everything we can to prevent it recurring in the future.

“This is not just about South Australia or wind farms, it is about how we make the transition to a new electricity system.”

October 19, 2016

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