On Friday 10 January just after 8pm, Western Power’s network automatic safety systems detected a sudden loss of power generation, affecting the power available to Western Power customers.
We understand that power outages can be inconvenient – however, our network responded exactly as designed to protect the overall integrity of the South West Interconnected System.
The unexpected power loss resulted in around 100,000 (or eight per cent) of our 1.2 million customer connections being automatically and instantaneously shut off to maintain security of the network and protect customer equipment.
This response is known as a load shedding and was needed to balance the network frequency to 50Hz, after dipping to 48.75Hz, which is essential to safely meet customer demand using the accessible generation at the time.
In less than one second the automated systems assessed the entire network load and other real-time data to shed load throughout the network, creating a large number of emergency unplanned outages.
We immediately worked with the Australian Energy Market Operator (AEMO) who dispatched reserve and other online generators to make more generation available for us to return power back to impacted customers.
Within one hour of the extra generation supply being available to us, power had been restored to around 75,000 homes and businesses, with the remaining customers fully restored shortly before 11.30pm.
This type of large generation loss is very rare, and, while impossible to predict, Western Power’s intelligent designs systems are prepared to meet these unusual events almost instantaneously while delivering power safely and effectively.