A cold drink straight from the fridge on a summer’s day, waking-up to a heated house on a chilly winters’ morning, charging our smart phones, and expecting the lights to come on at the simple flick of a switch. These are all considered to be normal and even expected activities in our daily lives in first world countries. The electricity system is central to our modern lifestyle and day-to-day we rely on it more than we probably realise. To most consumers, this supply of energy is as simple as flicking a switch. However, the work that goes into producing and maintaining that supply, is far from simple.
Recently, Stanwell Power Station and Tarong Power Station were requested by the Australian Energy Market Operator (AEMO) to test their capability to “trip to house load” (TTHL). Each station has a contract with AEMO to provide system restart ancillary service – which means we would be asked to restart the electricity grid if the system was to “go black” – as happened in South Australia in 2016, when 1.7 million householders were left without power following severe storms.
The purpose of the test is to prove our power station’s capability to restore power to the grid in the event of a similar incident so that households would not be left in the dark.
As part of the tests, the selected units rolled back to operating at minimum operational load (approximately 16 MW) in response to a signal simulating a system “black” event. Additional tests at this load were completed before synchronising the unit and returning to normal load. Tests on both units were completed successfully, with Tarong Unit 1 having separated from the grid for over three hours – a new record for Tarong.
Stanwell Power Station’s Unit 3 TTHL test was successfully completed on Thursday 16 June. There is a compliance requirement to undertake a TTHL test after a major unit overhaul, and in this case, Unit 3 was nearly three years from its last major overhaul. This type of testing is a clear demonstration of the unit black start capability across the entire life cycle of our generating units.
Stanwell regularly participates in activities such as this, as part of our summer preparedness initiatives to ensure we can continue to deliver the energy Queensland needs. Our involvement in the trip to house load exercise is a great example of how our people continue to work smart and build capability by ensuring our systems are secure and integrated.