At 8:08 PM (AWST), unplanned generation outages in Western Australia's South West Interconnected System (SWIS) triggered automatic system protections that interrupted supply to consumers.
These automated system protections are in place to prevent long-term damage to system infrastructure, and protect consumers from the risk of a system-wide failure.
AEMO immediately dispatched additional reserve generation to restore the system frequency back to the safe operating levels, and at 8:27 PM (AWST) AEMO advised Western Power it could begin restoring power to the affected consumers.
Approximately 98,000 consumers were impacted by this supply interruption, and a large majority of users had their power restored within the hour. The final 2,000 consumers were restored by 11:30 PM (AWST).
In compliance with the Wholesale Electricity Market (WEM) Rules, AEMO will conduct a detailed investigation into the root cause of this failure, and has implemented temporary, special operational arrangements to protect the system while the investigation is underway. AEMO will publish the findings of this investigation once it is completed.
At this stage, the SWIS is in a stable, secure state, and there are currently no forecast lack of reserve (LOR) conditions. This means that our forecasts show we have enough supply and reserves to meet the anticipated demand in the SWIS. AEMO will provide updates if the conditions change, and will continue to operate the market and system in the interest of consumers.