Transformer incident at Liddell Power Station Unit 3 seriously injures a worker

What happened

On Thursday 17 December 2020 there was a transformer incident at Unit 3 of AGL's Liddell Power Station in New South Wales. A worker was seriously injured and was receiving medical attention. The unit was taken out of service. AGL said an investigation was under way, including engagement with the relevant authorities, and that it was assessing how long any outage might last. On a precautionary basis it told the Australian Energy Market Operator that the outage might last up to two and a half months, and it described that estimate as highly preliminary.

Reporting said the outage effectively removed 420 MW of supply for the summer. Shortly afterwards AEMO declared an actual Lack of Reserve Level 2 event and activated the Reliability and Emergency Reserve Trader mechanism. There was no indication of how much supply, or what technology, was called on, and there were no reports of load lost. Prices in the New South Wales region of the National Electricity Market spiked and later reached the market cap of $15,000 per MWh.

Contributing factors

The cause had not been determined. AGL said an investigation was under way to establish the cause of the transformer incident.

Lessons learned

1. An unplanned transformer incident on a large generating unit can remove hundreds of megawatts at short notice, so the owner should give the market operator an early outage estimate and mark it as preliminary until the assessment is finished.
2. A serious injury and an unexplained transformer incident should be investigated with the relevant authorities before the unit is treated as fit to return.
3. In a tight summer supply balance, loss of one large unit can lead the market operator to call emergency reserves, so owners should plan for the reliability impact of an extended transformer outage.

Source

reneweconomy.com.au